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The IPCC sea level numbers

Filed under: — stefan @ 27 March 2007 - (Português)

The sea level rise numbers published in the new IPCC report (the Fourth Assessment Report, AR4) have already caused considerable confusion. Many media articles and weblogs suggested there is good news on the sea level issue, with future sea level rise expected to be a lot less compared to the previous IPCC report (the Third Assessment Report, TAR). Some articles reported that IPCC had reduced its sea level projection from 88 cm to 59 cm (35 inches to 23 inches) , some even said it was reduced from 88 cm to 43 cm (17 inches), and there were several other versions as well (see “Broad Irony”). These statements are not correct and the new range up to 59 cm is not the full story. Here I will try to clarify what IPCC actually said and how these numbers were derived. (But if you want to skip the details, you can go straight to the critique or the bottom line).

What does IPCC say?

The Summary for Policy Makers (SPM) released last month provides the following table of sea level rise projections:

Sea Level Rise
(m at 2090-2099 relative to 1980-1999)
Case Model-based range
excluding future rapid dynamical
changes in ice flow
B1 scenario 0.18 – 0.38
A1T scenario 0.20 – 0.45
B2 scenario 0.20 – 0.43
A1B scenario 0.21 – 0.48
A2 scenario 0.23 – 0.51
A1FI scenario 0.26 – 0.59

It is this table on which the often-cited range of 18 to 59 cm is based. The accompanying text reads:

• Model-based projections of global average sea level rise at the end of the 21st century (2090-2099) are shown in Table SPM-3. For each scenario, the midpoint of the range in Table SPM-3 is within 10% of the TAR model average for 2090-2099. The ranges are narrower than in the TAR mainly because of improved information about some uncertainties in the projected contributions15. {10.6}.

Footnote 15: TAR projections were made for 2100, whereas projections in this Report are for 2090-2099. The TAR would have had similar ranges to those in Table SPM-3 if it had treated the uncertainties in the same way.

• Models used to date do not include uncertainties in climate-carbon cycle feedback nor do they include the full effects of changes in ice sheet flow, because a basis in published literature is lacking. The projections include a contribution due to increased ice flow from Greenland and Antarctica at the rates observed for 1993-2003, but these flow rates could increase or decrease in the future. For example, if this contribution were to grow linearly with global average temperature change, the upper ranges of sea level rise for SRES scenarios shown in Table SPM-3 would increase by 0.1 m to 0.2 m. Larger values cannot be excluded, but understanding of these effects is too limited to assess their likelihood or provide a best estimate or an upper bound for sea level rise. {10.6}

• If radiative forcing were to be stabilized in 2100 at A1B levels, thermal expansion alone would lead to 0.3 to 0.8 m of sea level rise by 2300 (relative to 1980–1999). Thermal expansion would continue for many centuries, due to the time required to transport heat into the deep ocean. {10.7}

• Contraction of the Greenland ice sheet is projected to continue to contribute to sea level rise after 2100. Current models suggest ice mass losses increase with temperature more rapidly than gains due to precipitation and that the surface mass balance becomes negative at a global average warming (relative to pre-industrial values) in excess of 1.9 to 4.6°C. If a negative surface mass balance were sustained for millennia, that would lead to virtually complete elimination of the Greenland ice sheet and a resulting contribution to sea level rise of about 7 m. The corresponding future temperatures in Greenland are comparable to those inferred for the last interglacial period 125,000 years ago, when paleoclimatic information suggests reductions of polar land ice extent and 4 to 6 m of sea level rise. {6.4, 10.7}

• Dynamical processes related to ice flow not included in current models but suggested by recent observations could increase the vulnerability of the ice sheets to warming, increasing future sea level rise. Understanding of these processes is limited and there is no consensus on their magnitude. {4.6, 10.7}

• Current global model studies project that the Antarctic ice sheet will remain too cold for widespread surface melting and is expected to gain in mass due to increased snowfall. However, net loss of ice mass could occur if dynamical ice discharge dominates the ice sheet mass balance. {10.7}

• Both past and future anthropogenic carbon dioxide emissions will continue to contribute to warming and sea level rise for more than a millennium, due to the timescales required for removal of this gas from the atmosphere. {7.3, 10.3}

(The above quotes document everything the SPM says about future sea level rise. The numbers in wavy brackets refer to the chapters of the full report, to be released in May.)

What is included in these sea level numbers?

Let us have a look at how these numbers were derived. They are made up of four components: thermal expansion, glaciers and ice caps (those exclude the Greenland and Antarctic ice sheets), ice sheet surface mass balance, and ice sheet dynamical imbalance.

1. Thermal expansion (warmer ocean water takes up more space) is computed from coupled climate models. These include ocean circulation models and can thus estimate where and how fast the surface warming penetrates into the ocean depths.

2. The contribution from glaciers and ice caps (not including Greenland and Antarctica), on the other hand, is computed from a simple empirical formula linking global mean temperature to mass loss (equivalent to a rate of sea level rise), based on observed data from 1963 to 2003. This takes into account that glaciers slowly disappear and therefore stop contributing – the total amount of glacier ice left is actually only enough to raise sea level by 15-37 cm.

3. The contribution from the two major ice sheets is split into two parts. What is called surface mass balance refers simply to snowfall minus surface ablation (ablation is melting plus sublimation). This is computed from an ice sheet surface mass balance model, with the snowfall amounts and temperatures derived from a high-resolution atmospheric circulation model. This is not the same as the coupled models used for the IPCC temperature projections, so results from this model are scaled to mimic different coupled models and different climate scenarios. (A fine point: this surface mass balance does include some “slow” changes in ice flow, but this is a minor contribution.)

4. Finally, there is another way how ice sheets can contribute to sea level rise: rather than melting at the surface, they can start to flow more rapidly. This is in fact increasingly observed around the edges of Greenland and Antarctica in recent years: outlet glaciers and ice streams that drain the ice sheets have greatly accelerated their flow. Numerous processes contribute to this, including the removal of buttressing ice shelves (i.e., ice tongues floating on water but in places anchored on islands or underwater rocks) or the lubrication of the ice sheet base by meltwater trickling down from the surface through cracks. These processes cannot yet be properly modelled, but observations suggest that they have contributed 0 – 0.7 mm/year to sea level rise during the period 1993-2003. The projections in the table given above assume that this contribution simply remains constant until the end of this century.

As an example, take the A1FI scenario – this is the warmest and therefore defines the upper limits of the sea level range. The “best” estimates for this scenario are 28 cm for thermal expansion, 12 cm for glaciers and -3 cm for the ice sheet mass balance – note the IPCC still assumes that Antarctica gains more mass in this manner than Greenland loses. Added to this is a term according to (4) simply based on the assumption that the accelerated ice flow observed 1993-2003 remains constant ever after, adding another 3 cm by the year 2095. In total, this adds up to 40 cm, with an ice sheet contribution of zero. (Another fine point: This is slightly less than the central estimate of 43 cm for the A1FI scenario that was reported in the media, taken from earlier drafts of the SPM, because those 43 cm was not the sum of the individual best estimates for the different contributing factors, but rather it was the mid-point of the uncertainty range, which is slightly higher as some uncertainties are skewed towards high values.)

How do the new numbers compare to the previous report?


Sea level rise as observed (from Church and White 2006) shown in red up to the year 2001, together with the IPCC (2001) scenarios for 1990-2100. See second figure below for a zoom into the period of overlap.

The TAR showed sea level rise curves for a range of emission scenarios (shown in the Figure above together with the new observational record of Church and White 2006). The range was based on simulations with a simple model (the MAGICC model) tuned to mimic the behaviour of a range of different complex climate models (e.g. in terms of different climate sensitivities ranging from 1.7 to 4.2 ºC), combined with simple equations for the glacier and ice sheet mass balances (“degree-days scheme”). This model-based range is shown as the grey band (labelled “Several models all SRES envelope” in the original Figure 5 of the TAR SPM) and ranged from 21 to 70 cm, while the central estimate for each emission scenario is shown as a coloured dashed line. The largest central estimate of sea level rise is for the A1FI scenario (purple, 49 cm).
In addition, the dashed grey lines indicate additional uncertainty in ice sheet behaviour. These lines were labelled “All SRES envelope including land ice uncertainty” in the TAR SPM and extended the range up to 88 cm, adding 18 cm at the top end. One has to delve deeply into the appendix of Chapter 11 of the TAR to find out what these extra 18 cm entail: they include a “mass balance uncertainty” and an “ice dynamic uncertainty”, where the latter is simply assumed to be 10% of the total computed mass loss of the Greenland ice sheet. Note that such an ice dynamic uncertainty was only included for Greenland but not for Antarctica; instability of the West Antarctic Ice Sheet, a scenario considered “very unlikely” in the TAR, was explicitly not included in the upper limit of 88 cm.

As we mentioned in our post on the release of the SPM, it is apples and oranges to say that IPCC reduced the upper sea level limit from 88 cm to 59 cm, as the former included “ice dynamic uncertainty” (albeit only for Greenland, as rapid ice flow changes in Antarctica were considered too unlikely to bother at the time), while the latter discusses this ice flow uncertainty separately in the text, stating it could add 10 cm, 20 cm or even more to the 59 cm in the table.

So is it better to compare the model-based range 21 – 70 cm from the TAR to the 18 – 59 cm from the AR4? Even that is apples and oranges. For one, TAR cites the rise up to the year 2100, the AR4 up to the period 2090-2099, thus missing the last 5 years (or 5.5 years, but let’s not get too pedantic) of sea level rise. For 2095, the TAR projection reduces from 70 cm to 65 cm (the central estimate for A1FI reduces from 49 cm to 46 cm). Also, the TAR range is a 95% confidence interval, the AR4 range a narrower 90% confidence interval. Giving the TAR numbers also as 90% ranges shaves another 3 cm off the top end.

Sounds complicated? There are some more technical differences… but I will spare you those. The Paris IPCC meeting actually discussed the request from some delegates to provide a direct comparison of the AR4 and TAR numbers, but declined to do this in detail for being too complicated. The result was the two statements:

The TAR would have had similar ranges to those in Table SPM-3 if it had treated the uncertainties in the same way.

and

For each scenario, the midpoint of the range in Table SPM-3 is within 10% of the TAR model average for 2090-2099.

(In fact delegates were told by the IPCC authors in Paris that with the new AR4 models, the central estimate for each scenario is slightly higher that with the old models, if numbers are reported in a comparable manner.)

The bottom line is thus that the methods have significantly improved (which is the reason behind all those methodological changes), but the expectation of how much sea level will rise in the coming century has not significantly changed. The biggest change is that ice sheet dynamics look more uncertain now than at the time of the TAR, which is why this uncertainty is not included any more in the cited range but discussed separately in the text.

Critique – Could these numbers underestimate future sea level rise?

There’s a number of issues worth discussing about these sea level numbers.

The first is the treatment of potential rapid changes in ice flow (item 4 on the list above). The AR4 notes that the ice sheets have been losing mass recently (the analysis period is 1993-2003). Greenland has contributed +0.14 to +0.28 mm/year of sea level rise over this period, while for Antarctica the uncertainty range is -0.14 to +0.55 mm/year. It is noted that the mass loss of Antarctica is mostly or entirely due to recent changes in ice flow. The question then is: how much will this process contribute to future sea level rise? The honest answer is: we don’t know. As the SPM states, by the year 2095 it could be 10 cm. Or 20 cm. Or more. Or less.

The IPCC included one guess into the “model-based range” provided in the table: it took half of the Greenland mass loss and the whole Antarctic mass loss for 1993-2003, and assumed this would remain constant ever after until 2100. This assumption in my view has no scientific basis, as the ice-flow is almost certainly highly variable in time. The report itself states that this ice loss is due to a recent acceleration of flow, and that in 2005 it was already higher, and that in future the numbers could be several times higher – or they could be lower. Adding such an ill-founded number into the “model-based” range degrades the much more reliable estimates for thermal expansion, mountain glaciers and mass balance. Even worse: to numbers with error estimates, it adds a number without proper error estimate (the observational uncertainty for 1993-2003 is included, but who would claim this is an error estimation for future ice flow changes?). And then it presents only the combined error margins – you will notice that no central estimate is provided in the above table. If I had presented this as an error calculation in a first-semester physics assignment, I doubt I would have gotten away with it. The German delegation in Paris (of which I was a member) therefore suggested taking this ice-flow estimate out of the tabulated range. The numbers would have become slightly lower, but this approach would not have mixed up very different levels of uncertainty, and it would have been clear what is included in the table and what is not (namely ice flow changes), rather than attempting to partially include ice flow changes. The ice flow changes could have been discussed in the text – stating there that at the 1993-2003 rate, this term would contribute 3 cm by 2095, but it is bound to change and could turn out to be 10 cm or 20 cm or more. However, we found no support for this proposal, which would not have changed the science in any way but improved the clarity of presentation.

As it is now, because of the complex and opaque way of combining the errors, even I could not tell you by how much the upper limit of 59 cm would be reduced if the questionable ice flow estimate was taken out, and one of the reasons provided by the IPCC authors for not adopting our proposal was that the numbers could not be calculated quickly.

A second problem with the above range is that the models used to derive this projection significantly underestimate past sea level rise. We tried in vain to get this mentioned in the SPM, so you have to go to the main report to find this information. The AR4 states that for the period 1961-2003, the models on average give a rise of 1.2 mm/year, while the data show 1.8 mm/year, i.e. a 50% faster rise. This is despite using observed ice sheet mass loss (0.19 mm/year) in the “modelled” number in this comparison, otherwise the discrepancy would be even larger – the ice sheet models predict that the ice sheets gain mass due to global warming. The comparison looks somewhat better for the period 1993-2003, where the “models” give a rise of 2.6 mm/year while the data give 3.1 mm/year. But again the “models” estimate includes an observed ice sheet mass loss term of 0.41 mm/year whereas ice sheet models give a mass gain of 0.1 mm/year for this period; considering this, observed rise is again 50% faster than the best model estimate for this period. This underestimation carries over from the TAR models (see Rahmstorf et al. 2007 and the Figure below) – this is not surprising, since the new models give essentially the same results as the old models, as discussed above.


Comparison of the 2001 IPCC sea-level scenarios (starting in 1990) and observed data: the Church and White (2006) data based primarily on tide gauges (annual, red) and the satellite altimeter data (updated from Cazenave and Nerem 2004, 3-month data spacing, blue, up to mid-2006) are shown with their trend lines. Note that the observed sea level rise tends to follow the uppermost dashed line of the IPCC scenarios, namely the one “including land ice uncertainty”, see first Figure.

We therefore see that sea level appears to be rising about 50% faster than models suggest – consistently for the 1961-2003 and the 1993-2003 periods, and for the TAR models and the AR4 models. This could have a number of different reasons, and the discrepancy could be considered not significant given the error ranges of observations and models. It is no proof that models underestimate future sea level rise. But it is at least a plausible possibility that the models may underestimate future rise.

A third issue worth mentioning is that of carbon cycle feedback. The temperature projections provided in table SPM-3 of the Summary for Policy Makers range from 1.1 to 6.4 ºC warming and include carbon cycle feedback. The sea level range, however, is based on scenarios that exclude this feedback and thus only range up to 4.5 5.2 ºC. This could easily be misunderstood, as in table SPM-3 the temperature ranges including carbon cycle feedback are shown right next to the sea level ranges, but the latter actually apply to a smaller temperature range. As a rough estimate, I suggest that for a 6.4 ºC warming scenario, of the order of 20 15 cm would have to be added to the 59 cm defining the upper end of the sea level range.

A final point is the regional aspects. Planners of coastal defences need to be aware that sea level rise will not be the same everywhere. The AR4 shows a map of regional sea level changes, which shows that e.g. European coasts can expect a rise by 5-15 cm more than the global mean rise – that is a model average, not including an uncertainty range. The pattern in this map is remarkably similar to that expected from a slowdown in thermohaline circulation (see Levermann et al. 2005) so probably it is dominated by this effect. In addition, some land areas are rising and some are subsiding in response to the end of the last Ice Age or due to local anthropogenic processes (e.g. groundwater withdrawal), which local planners need to account for.

The bottom line

The main conclusion of this analysis is that sea level uncertainty is not smaller now than it was at the time of the TAR, and that quoting the 18-59 cm range of sea level rise, as many media articles have done, is not telling the full story. 59 cm is unfortunately not the “worst case”. It does not include the full ice sheet uncertainty, which could add 20 cm or even more. It does not cover the full “likely” temperature range given in the AR4 (up to 6.4 ºC) – correcting for that could again roughly add 20 15 cm. It does not account for the fact that past sea level rise is underestimated by the models for reasons that are unclear. Considering these issues, a sea level rise exceeding one metre can in my view by no means ruled out. In a completely different analysis, based only on a simple correlation of observed sea level rise and temperature, I came to a similar conclusion. As stated in that paper, my point here is not that I predict that sea level rise will be higher than IPCC suggests, or that the IPCC estimates for sea level are wrong in any way. My point is that in terms of a risk assessment, the uncertainty range that one needs to consider is in my view substantially larger than 18-59 cm.

A final thought: this discussion has all been about sea level rise until the year 2095. Sea level rise does not end there, as the quotes from the SPM at the beginning of this article show. Over several centuries, without serious mitigation efforts we may expect several meters of sea level rise. The Advisory Council on Global Change of the German government (disclosure: I’m a member of this body) in its recent special report on the oceans has proposed to limit long-term sea level rise to a maximum of one meter, as a guard-rail to guide climate policy. But that’s another story.

Update: I was just informed by one of the IPCC authors that the temperature scenarios without carbon cycle feedback range up to 5.2 ºC, not 4.5 ºC as I had assumed. This number is not found in the IPCC report; I had tried to interpret it from a graph, but not accurately enough. My apologies! The numbers in the text above that had to be corrected are marked by strikethrough font. -stefan


308 Responses to “The IPCC sea level numbers”

  1. 251
    kat mccarthy says:

    i posted a post on “gardening by the globe”, it recieved only 4 comments but was viewed by over 50 people and i got a email from one of the big shots on there who said my post would be deleted,here is what she wrote to me

    Community Stats: 52964 forum posts, 1449 entries in 85 blogs have been added by 1464 members.

    from the forum on gardenstew….
    Home | Forums | Blogs | Calendar | Plants | | 14 new posts | 1 new blog entries

    Inbox :: Message
    From: toni
    To: katsback
    Posted: Sat Apr 07, 2007 2:05 am
    Subject: The Global warming topic
    Kat,
    This topic is becoming too volatile and political so for the sake of the entire forum it will have to be deleted.

    If you wish to argue about whether global warming is coming immediately please find a forum where that topic is allowed.
    In a discussion, each persons opinion has just as much importance as anyone elses whether they agree with you or not.

    Toni
    co-moderator

    i feel it shouldnt have been deleted, i just wish i could have sent you the post,it was deleted before i had a chance to save it!

    the world has no chance of ever being saved if people like that are in charge!!!

  2. 252
    Ray Ladbury says:

    Kat, unfortunately, the forum is geared to a particular group and the moderators have to exercise their judgement as to whether a particular subject is so controversial that it threatens to sew animosity. I do think that it would be appropriate to ask for guidance–is the entire subject of climate change off limits (an unreasonable, but probably legal position) or are there tight limits on tone, etc. that should be taken.
    You are right, climate change is a crucial subject and should be of concern to any gardener that thinks about invasives, pests, etc.

  3. 253
    Lynn Vincentnathan says:

    RE #250 (&249), I hope I wasn’t assuming a coupled model (except hoping for one between warming & positive feedbacks). I was imagining that they feed in different emissions amounts into the warming models & thus the different scenarios (the models working very well with small confidence intervals). And then the economists taking their scenarios and feeding them into their own models-of-sorts to see how these might impact our economic situations, and for each climate story coming up with various econ stories, because if climate is complicated, the econ aspects become even more complicated with wild card factors.

    And I was dead serious (tho exaggerating) re $trillions in diamond or food. Bec macroeconomics does not really distinguish between these. It does not address what is biologically needed to sustain life. And even microoeconomics only gets at our desires, not our biological needs.

    Which is why I would never leave the world’s fate in the hands of neoclassical economists alone. Biologists and others need to weigh in on how GW will impact the world.

    And when I say “prudent” I in no way refer to my own risk (tho from experience I’ve found I only save money without reducing living standards by reducing GHGs — that’s just a plus). Prudent means for the entire world into its distant future. My sole motivation is to reduce my killing of people & other biota now and for many millennia. So the prudent path for me is to reduce GHGs as much as possible.

    If others don’t mind killing people willy nilly now & into the distant future (bec they are having too much fun living wasteful, inefficient lives — they sort of remind me of those nasty boys who delighted in kicking down my sand castles), then that’s their bag. I’d only hope more people and governments would choose good rather than bad for the sake of the world and for their souls.

  4. 254
    Lynn Vincentnathan says:

    RE #249, I feel funny about “carbon offsets.” I think it’s fine to give carbon offset gifts — like giving people CF bulbs or low-flow showerheads, rather than traditional gifts or charities.

    However, we must actually reduce our GHGs, not simply buy the right to spew them bec supposedly someone else is reducing for us (they may have thrown that CF bulb away, for all I know).

    So carbon offsets can be used, but mainly as carbon offset gifts – the gift that keeps on giving. But instead of buying offsets to drive the same as usual, why not move closer to work, or take a shorter vacation, or run multiple errands, or turn off the motor in drive-thrus. Or buy an EV and plug it into your all wind power electricity (that’s what I hope to do as soon as such vehicles are available at an affordable price — which they should be, since they are so much more simple than ICE cars).

    Then buy those offsets anyway to help others reduce.

  5. 255
    Tim McDermott says:

    re Steven Mosher:

    Put another way. We cant afford to get that hot, so we won’t. Behavior will change, or people are not rational. And I refuse to be a fascist and bleive that people are not rational.

    Unfortunately, people are not always rational, and large aggregations of people are often not rational. Your assertion that this observation makes me a fascist speaks more to you limited observation of the world than to my political leanings.

    First, if people were rational, the US wouldn’t have 30,000 deaths from drug abuse every year, nor would we arrest 2 million folks on drug charges. If markets were rational, we would not have crashes like 1929 or 1987.

    You are right that behavior will change, but the obvious effects of AGW lag the causitive bahavior. In the case of sea level rise, it may well go on for 800 years after the behavior stops. If there are hidden triggers in the system that amplify warming (and it takes a lot of faith in a lenient, protective God to believe there are none) then we are in deep trouble before the mass of humanity sees the need to change.

    Finally, you say “In fact, one could say that increasng your emissions is POSITIVELY CORRELATED with wealth. “ This is simply not true. In the decade or so after the 1973 oil shock, Japan decreased energy consumption by 1/3 while doubling GDP. Even today, Japan, Britain, Germany, and France produce about half the CO2 per capita that the US does.

    The thing that frustrates me the most about the discussions of AGW is assumption that mitigation will depress standards of living. That is only true if we are too dense to imagine, and then develop alternate ways to generate and consume energy. The country that develops effective renewable energy sources first will be more prosperous than the rest of the world for generations. The other mostly ignored factor in the economic debate is what the status quo costs. The US ships about $30 billion per month to pay for imported oil. We spend (by my calculations) about another $20 billion a month to protect overseas oil supplies. Western dependence on Middle Eastern oil funds Islamic terrorism.

    Conservation and renewable energy sources are the only path to energy independence. Energy independence solves a lot of our current problems.

  6. 256
    Dave Rado says:

    re. 255

    That is only true if we are too dense to imagine, and then develop alternate ways to generate and consume energy.

    It’s at least as much about pointless wastage. The main reason European countries use well under half as much energy per capita as the US is that they don’t waste as much, but even in Europe we waste a ridiculous amount. Over 80% of houses in the UK aren’t insulated properly. Over 90% use inefficient light bulbs. A huge percentage of people in the UK go on regular car trips of well under a mile (I’ve forgotten the percentage but it’s incredibly high). Cycling or walking for such short journeys wouldn’t only save energy but would increase health and reduce traffic jams. Most shops and offices leave large numbers of incandescent lights on all night (frequently halogen lights, the most inefficient ones of all), even in well lit street with CCTV. Most street lighting could be solar and is not. Our electricity grid is incredibly inefficient; a decentralised grid could increase efficiency by around 40%. Almost all existing cars could be converted to LPG for a fairly low outlay that would typically pay for itself in 2-3 years, and that would reduce emissions from cars by 20%. New cars, even without using alternative fuels, could use fuel around 30% more efficiently than they do on average, using existing technologies. Glorification of SUVs has nothing to do with standards of living, and there are many fuel-efficient cars that are a pleasure to drive. Most people throw away several plastic carrier bags every time they go shopping, when they could get a couple of sturdy shopping bags that last a lifetime and use them. I could give hundreds of other examples. We could cut our energy usage dramatically with no technology breakthroughs whatsoever, and with no reduction in living standards whatsoever – it’s just a matter of wanting to. At the moment most of us simply don’t care enough to want to, although many of us pretend that we care.

  7. 257
    Dave Rado says:

    RE. 254, you can’t reduce your emisssions to zero. Reduce them as much as you feel you can, and offset the rest.

  8. 258
    Dave Rado says:

    Re. 255

    The thing that frustrates me the most about the discussions of AGW is assumption that mitigation will depress standards of living. That is only true if we are too dense to imagine, and then develop alternate ways to generate and consume energy

    Even more that is only true to the extent that we continue to be addicted to waste and inefficiency. Living standards in Western Europe are broadly similar to those in the US but per capita CO2 emissions in Western Europe are less than half those in the US, and that is almost entirely due to waste and inefficiency. And even in Western Europe waste and inefficiency is extraordinarily high. We could probably cut emissions in Europe by 50% purely by reducing waste and inefficiency, with no need for any new technologies at all. But the political will isn’t there currently.

  9. 259
    Michael says:

    As countries such as the UK (eg through its Climate Change Bill and associated measures) move to implement high-impact energy-conservation and efficiency, resource efficiency and waste minimisation, green business strategies etc, the US seems (from the outside) to remain entrenched in old-world dogmas that to go green is bad for business and bad for the economy.

    If going green (through integrated implementation of the above plus implementation of businesss ecointelligence etc) can strip huge costs out of a business and improve competitiveness and facilitate entry into and formation of the emerging green markets, as well as (when implemented across the economy) delivering carbon downsizing on the massive scale required to suppress climate change and its impacts as far as possible, then it must make business sense and planet sense.

    The longer the US decides not to implement full-scale high-velocity carbon downsizing on a national scale, the greater the opportunity for its businesses and industries to be competitively zapped when world markets transition. Making an ultra-fast transition to becoming ultra-low carbon is equivalent to becoming highly competitive and at the same time brings powerful positive benefits to climate change mitigation.

    Those who argue that the US should resist attempts to maintain / become competitive through carbon downsizing have not really thought it through. They might not put it in those terms – for example, they might argue that climate change mitigation is too costly – but the effect of their digging-in-of-heels and addiction to the past is the same.

    Finally, to keep this post on thread (IPCC sea level numbers), like the ice melt that is flooding down the moulins, there is a phrase that one could use about where US businesses and industries might flush if its leaders don’t rise to the global competitive challenge and carbon downsizing opportunity.

  10. 260
    Lynn Vincentnathan says:

    #255, fully agreed. When I first started outreaching to people in the early 90s to reduce their GHGs cost-effectively (& save money, without lowering living standards, as I had done & and knew thru experience was quite doable), and in that way reduce harm from GW & other environmental problems (& other – as you mentioned – harms & expenses), I thought all I’d have to do is tell people, start the ball rolling, then get back to “my life.”

    I thought the regular people (not drug addicts, of course) were rational enough to want to save money or do good (at no cost, even savings). But alas alack, they simply are not rational! I can’t even get goody-two-shoes religious people to reduce GHGs cost-effectively for the sake of saving the world for their progeny. The anti-abortion activists seem to be the most opposed to even believing GW is real, and couldn’t care less about all the other harms, such as “natural” abortions from local pollution. It is the hardest nut to crack I’ve ever experienced.

    OTOH, it was not rationality that motivated me, but a profound conversion experience or change of heart. I was reviewing the film IS IT HOT ENOUGH FOR YOU? (about GW) in 1990, a film I had shown my classes several times. Nothing new. All of a sudden during the part about drought starvation in Africa I cried out (internally), “Why don’t they do something about this?” Then it hit me like a tons of bricks. “I’m the one causing this. I have to do something.”

    That was around Ash Wednesday of 1990. I spent Lent in anguish not knowing what to do, caught up in structures of high GHG emissions (knowing my husband would not go along with a primitive lifestyle). I was the Good Thief on the cross, repentant but unable to correct my fault, until I realized I was the Roman soldier pounding in the nail – forgiven, but unable to stop my killing.

    Then the week after Easter I went to the Earth Day fair & watched Earth Day TV programs, and began to realize there were solutions. But it was mainly many many little things (turning off the water while brushing teeth, etc), and a few big things.

    Over the years I reduced by about 1/3, then went on Green Mountain 100% wind powered electricity. And I’m counting GHGs from all things, not just gasoline & electricity. All products and water have GHG components. REDUCE, REUSE, RECYCLE can go a long way to reducing GHGs. And now I’m awaiting plug-in hybrids, which will be a high cost for us, but our savings over the past 17 years from reducing GHGs should help off-set that cost.

    So rationality does NOT work. Our only hope is if many many people & businesses & our gov have conversion experiences that touch their hearts, open them to reducing GHGs. The actual changes and implementations of GHG reduction measures then become easy by comparison.

  11. 261
    Lynn Vincentnathan says:

    #259, that catchy about the moulins. “Don’t flush the world down the moulins.” Then let people ask, “What are moulins?” Then let them find out.

    And just in time for Earth Day.

  12. 262
    Steven Mosher says:

    Well, I can’t begin to answer all of the various comments so, I’ll just point out a few things.

    First, as a stated above my main concern is not with the climate science or the models used to make future projections. But every good modeler knows “garbage in; garbage out. I would recommend that everyone read the SRES. you can find it on the IPCC site. Here is a link to the emmission scenarios

    http://www.grida.no/climate/ipcc/emission/116.htm

    Note the huge spread in emission assumptions. What this indicates to me is a very large uncertainty in the future of emmissions. So, who decides what scenarios to use. Some of them are scary; sme benign

    Now, as I read it the models are fed with data from the scenarios. The output of the models do not feedback into the scenarios. I’m somewhat suspect of this.

    Second, the scenarios are broadly classified into 2 dimensions. The dimension that intersts me is the A/B dimension. In the A scenarios people are driven toward economic development. In the B scenarios the drivers are Enviromentalism, roughly speaking. So, for example in A1F1,
    the scennario that shows the highest sea level rise, there is a global focus on economic development and there is a focus on Fossile fuels.
    According to this scenario sea level goes up between .26 and .59 meters.
    In the B1 scenario there is a global drive ( the one indicates global as opposed to regional ) toward eniroment concerns. And here you see a rise of .18 to .38 ( i think the average over the past 100 years is something like .2)

    Anyways, these two scenarios are given equal weight. Now read through the AIF1 scenario. In shrt form, it assumes the entire world will start to follow a US strategy with regards to economic development and fossile fuel usage. Not very sensible, not very probable. Yet, it’s given equal weight and it drives the highend of the estimates in the models. Put anotherway, AIF1 is not realistic because its not sustainable. I suppose one includes it to motivate folks, but it kinda verges on a scare tactic.

    Now, with regards to the correlation between wealth and getting hotter.
    I’ll go look through the reports again. my initial impression from glancing at a couple numbers was that wealthier (global GDP) was warmer, and poorer was cooler. If true ( i’ll double check) then this also seems odd since a bunch of folks here seem to argue just the opposite. If being green were to lead to a poorer future, then of course one couldn’t rationally convince people to do it. One would have to scare them. The point is these data sets drive the models. Only goofballs question the science within the models, but it seems we ought to have a glance or two at the data driving them. At this point I just have a bunch of questions. I don’t see it discussed much. I could be wrong so I was hoping somebody else here had actually looked through the input data.

  13. 263
    Ray Ladbury says:

    Steven, I believe that the wealthier vs. poorer look mainly at short term wealth production, while the hard times fall in the medium to long term. Also, if you think the rest of the world is unlikely to follow the US example of short-term thinking, then you have a much rosier impression of humanity than I do. Humans do a poor job of perceiving risk–especially when the risk may seem a long way off. And the recent IPCC report can be looked at two ways. An altruist sees an assertion that the hardest hits will knock the poor and thinks we must address the problem or help the poor deal with it. One who is less altruistic thinks, “Hmm, I’d better not be poor.” Which attitude do you think predominates within our species.
    As to future supplies of fossil fuels, we have plenty of cheap dirty coal to bring about the toasty, warm future envisioned by the IPCC–and worse. This is the path we are on now, with roughly 40% of humanity in India and China VERY energy hungry and the US showing no sign of diminishing thirst for oil and othe cheap energy. To date, we have shown no more intelligence than a colony of yeast in fermenting grape juice. And I doubt that we will produce a good vintage.

  14. 264
    Hank Roberts says:

    > AIF1 is not realistic because its not sustainable.
    But it describes business as usual, and it describes what both India and China are doing now. That’s a big enough part of the world to be considered as a high end estimate.

    Nothing highly profitable is sustainable — natural stocks grow at the average three percent a year, broadly speaking. An economy growing faster than that is an extractive economy, able to generate a surplus to buy up other resources and extract those later.

    Remember the suggestion that the best economic approach to whaling was to liquidate the resource and put the money in the bank, because interest rates are higher on money than the rate of growth of whales.

  15. 265
    Michael says:

    Returns on investment on energy conservation etc are much greater than returns from the stock market.

  16. 266
    Nick Gotts says:

    Re #262. I think Steven has a good point, insofar as (AFAIK) none of the climate models include the results of adaptation, which could modify climatic outcomes considerable (and in either direction). For example, farmers and other land managers will certainly respond to climatic change (indeed, are already doing so), and to government or other mitigation initiatives, with complex consequences. Integrating land use change into climate models may be the next major step in improving them, but will be very hard.

    Re #260, #263. I think you are both too pessimistic. The greatest ground for optimism is that objectively, all individuals and institutions concerned about what happens more than two or three decades ahead now have a central common interest – cutting GHG emissions fast. What’s more, agreement between a relatively small number of governments could make a big difference – the G8 plus 5 major “developing” countries, representatives of which are to discuss climate change this summer, would certainly be enough. Indeed, even if a few of these were to refuse to cooperate, a sufficiently large and powerful coalition, able to exert economic pressure on all other states to fall in line, might still be possible. Of course, all are likely to want others to make the biggest sacrifices, no agreement reached this year is likely to go anything like far enough, and given Bush’s baleful influence, the chances of any agreement at all before 2009 are slim, but the political shift that is currently going on should not be underestimated – consider the views of likely candidates in the 2008 US presidential election, the way environmental issues have shot to the top of Australia’s political debate, the Stern report and its repercussions in the UK. Sufficient GHG emission reductions are going to require radical socio-political change, but the shift in direction has begun, and I believe it could be fast enough.

  17. 267
    Steven Mosher says:

    RE #263.
    Thanks Ray.. I’ll make a couple points. See what you think. I don’t think you’ve read the SRES. Have a look. Anyways You wrote:

    “Steven, I believe that the wealthier vs. poorer look mainly at short term wealth production, while the hard times fall in the medium to long term. Also, if you think the rest of the world is unlikely to follow the US example of short-term thinking, then you have a much rosier impression of humanity than I do.”

    Interesting. So you thnk that short term thinking is wrong. You think most people will think in a short term way, ie follow the US, So you would propsoe that a few people decide what is best for our long term interest? Put another way, you think that I have a rosy view of humanity because I believe they can figure out their rational interest. So are some people just smarter at figuring out my interest for me? and how do we decide who these deciders are? Can’t ask the stupid short termed thinkers now can we? I mean if they can’t spot their interest how could they pick leaders? Hmm..The main reason I think people can’t follow the US down a Fossil intense path is the MODELS say such a path will cause enormous economic impacts. Simply put, A1F1 assumes developing areas pursue our path. But the impact statements state the opposite. That those ares will be hit heaviest by warming. This relates to my initial complaint that the inputs to the models are not coupled to the outputs. But hey, thats looking at the long term.

    And you go on

    “Humans do a poor job of perceiving risk–especially when the risk may seem a long way off. And the recent IPCC report can be looked at two ways. An altruist sees an assertion that the hardest hits will knock the poor and thinks we must address the problem or help the poor deal with it. One who is less altruistic thinks, “Hmm, I’d better not be poor.” Which attitude do you think predominates within our species.”

    So essentially this is the same argument. Most people can’t assess risk.
    Most people don’t care about others. Therefore, some privaledged people will do it for them. Sorry. If most people can’t assess risk and won’t be altrusitic, then who will decide? And who will pick the deciders?
    According to you The majority of people of can’t assess risk or be trusted to do the right thing. A few posts back I think I called this philosophy fascist. That was overly harsh. let’s call it elitist.
    Don’t know why I did that. had a hunch I suppose that people would come out and say… most people are stupid, most people are evil, trust the master race. Good thing nobody took that bait!

    And then you wrote:

    “As to future supplies of fossil fuels, we have plenty of cheap dirty coal to bring about the toasty, warm future envisioned by the IPCC–and worse. This is the path we are on now, with roughly 40% of humanity in India and China VERY energy hungry and the US showing no sign of diminishing thirst for oil and othe cheap energy. To date, we have shown no more intelligence than a colony of yeast in fermenting grape juice. And I doubt that we will produce a good vintage. ”

    My mistake. I wasnt speaking to the SUPPLIES of Fossil fuels. I was speaking to a different issue. If china and India Follow the US, we will see economic impacts ( droughts, famine, dislocation, disease, see the impact report) before 2100. Simply, the economic activity in A1F1 is not sustainable because of the damage it inflicts. A1F1 assumes that fosile fuel can be consumed without enviroment damage and without economic impact. Like I said the climate outputs of the model are not fed back into the dataset.

    In short, A1F1 can’t happen. To put it another way, you can’t have it both ways. You can’t use a dataset (A1F1) that assumes you can emit with impunity and flourish economically ( A1F1 has some of the highest GDP) and then argue that emitting with impunity leads to economic disaster.

    Ah well, you can argue that, but that’s an emotional scare tactic. For some views of humanity these tactics are justfied.

    Lets see. basically you said people are stupid. Then you try to convince me ( i think I’m human) of something. But if I’m stupid, how can I be convinced? especially by an argument that people are stupid.Now, I can be threatened. You’ll go to hell. I can be bribed. You’ll go to heaven. But, if I’m stupid, then I can’t be convinced. Isn’t it kinda self defeating from a rhetorical point of view to convince your audience by telling them that people are stupid.
    Oh ya, except for us smart guys.

  18. 268
    Ray Ladbury says:

    Gee, Nick, did you see what China, Russia and Saudi Arabia managed to do to the recent Summary for Policy Makers–only remove any reference to scientific consensus. The fact remains that to date no country has undertaken any policy that meaningfully reduces CO2 emissions. So, I really do not find any comfort in the fact that politicians are making the right noises. They’ve been making the right noises on healthcare in the US for decades.

  19. 269
    John Mashey says:

    re: #266
    I don’t think the world is inherently doomed either, BUT:

    a) Reading Jared Diamond’s “Collapse” doesn’t make one believe that people consistently are able to make good long-term decisions. Perhaps we know more now, but it is still clear that many people are able to ignore even strong evidence.

    b) The AGW problem seems unusual, in that humans are just not used to dealing with causes whose lag-time to effects are decades/centuries. Many people think that AGW can’t be true because the temperature rise in the 20th century didn’t immediately track the CO2 buildup, i.e., they don’t understand the lag-times and inertia in the system.

  20. 270
    Mark A. York says:

    Interestingly, moulins are a key plot point/device in my novel Warm Front. I think I used them in a way no one else has.

  21. 271
    Louis Hooffstetter says:

    Let me truthanize everyone. THE FACTS: 1) Global climate (and sea level) has NEVER remained constant. It is ALWAYS gradually changing in one direction or another. 2) Over the last 20,000 years, the earth has warmed enough to raise sea level 400 feet WITHOUT ANY ANTHROPOGENIC INFLUENCE! 3) Even if we abandon the planet or become extinct, SEA LEVEL WILL CONTINUE TO RISE! (just probably not as fast). 4) We can’t stop it, nor should we try (it’s NATURAL). While I am VERY MUCH in favor of limiting/reducing GHGs, preserving our oceans, and reducing habitat loss worldwide, it is a waste of time and energy to worry about a piddling 18 to 59 cm rise in sea level over the next 100 years. Instead of worrying about what causes sea level change and how to stop it, (because WE CAN”T!), we should figure out how to manage it and live with it. “let me assert my firm belief that the only thing we have to fear is fear itself – nameless, unreasoning, unjustified terror which paralyzes needed efforts to convert retreat into advance” FDR

    [Response: Hemlock is natural but I wouldn't advise eating any. The issue is whether we can avoid really big sea level rises due to melting ice sheets - if that starts to happen, there will have been nothing 'natural' about it. -gavin]

  22. 272
    Steven Mosher says:

    #264.

    Hi hank. Thanks for your thoughful comments. Have a look at the SRES. It makes for good reading. Just google SRES IPCC. Since you were kind enough to respond, I’ll make a few comments back. Ok?

    You wrote:

    “But it describes business as usual, and it describes what both India and China are doing now. That’s a big enough part of the world to be considered as a high end estimate.”

    Yes, that is roughly correct. My issue is this. The SRES dataset make assumptions for the next 100 years about emmissions. These emission assumptions are driven by scenario assumptions. Like so: assume china, India and the whole developing world follow the US….. they spew C02 like the US does… over time.

    From this Assumptipon about the futur, you get, roughly, a decade by decade projection of emmissions.So much C02. so much methane, land use like this, deforstation like that, cement production like this, population like so ( fun stories, you should read them. population control SHOULD be high on our agenda, according to the data). But in A1F1, by 2100 we are all hot and wet. ( ok sorry about that, but we all need to laugh ok)

    This is issue.

    INTERMEDIATE RESULTS. ( say 2050 results) of climate models are not fed back into the datasets to make adjustments to the economic activity assumptions, land use assumptions etc underlying them. In short, A1F1 assumes that people will continue to act in stupid, ignorant destructive ways when their countries suffer. When their countries are drought ridden, disease ridden, flooded, refugee ridden, hurrican ridden..In short, A1F1 assumes that people are too stupid to realize their behavior is destroying the world they live in. Even when they are knee deep in sea water. Even when malaria kills their kids. Even when…. If people are this stupid, they need to be controlled and governed by those us us who know better.
    They will appreciate it. In the end. We should control them… Opps.

    A1F1 assumes that people can continue to act in these ways, despite being, parched, infested,drowned, and living in tent cities. Huh? Global warming will have an impact on economic activity. In the AiF1 scenario, it does not. In that scenario everyone burns carbon and gets richer. What the F over?. Why input Junk assumptions into validated models? WHY?

    Now, we know that if the A1F1 predictions are right, if our coast areas flood, that economic activity WILL change. But….A1F1 scenarios predict GDPs at TWICE the level of B2 GDPS (futures where we think global act local) So, I find this funny. The hot future under water is projected to be better off economcally. Nobody beleives this is a realistic future.

    Then you wrote:

    “Nothing highly profitable is sustainable — natural stocks grow at the average three percent a year, broadly speaking. An economy growing faster than that is an extractive economy, able to generate a surplus to buy up other resources and extract those later.”

    I believe the A1F1 scenario.. maybe the A1B is the 3% per year model. BUT you make my point. Thanks. A1F1 assumes sustainable economic activity over the next 100 years, regardless of enviromental impact. You are right A1F1 is a crock. Opps, that was my point.A1F1 philosophy is this: growh rate has been 3% since 1850, it will be 3% until 2100. REGARDLESS OF WHAT WE SPEW. We will emit like hell, and this growth rate will not be impacted. Climate be damned. That is the asumption of A1F1, and you know it’s false. I call that a fairy tale.

    If you give people a choice between B2 ( 200-250 Trillion GDP) and A1 ( 500-550 Trillion GDP) only irrational fools will pick the green B2 . Hmm, I didnt say that. maybe I should argue FOR A1F1. Hot wet rich and dirty.

    But.. I wonder..let me simplify this because I have not been clear… From 100000000 feet:

    F(Economic activity) = emissions;
    F(Emissions )= warming;
    F(Warming) = sealevel;
    F(sealevel ) = economic activity;

    To explain the last. F(sealevel) = economic activity: New york under water. Flooded coast ain’t good for bidness. we could also substitute F(climatechange) = economic activity. Hot drought ridden land doesnt grow food!. See the impact statement.

    Now, clearly the entire model insinuates that economic activity ( choice of fuel types, population, etc etc) drives carbon, which drives the enviroment, which drives economic activity. So feedback. The whole POINT of policy recommendations is that there is a feedback loop. BUT, the modelling approach doesnt use a feedback loop. The climate science is great. The policy loop is disconnected. So, you can predict debates in that area. See, we are having one. Confirmed.

    Anyways,the SRES scenarios are static. That is, the last term, where we would feedback the climate outputs ( sea level, temp etc) to MODIFY the inputs ( economic activity) is missing. The models run Open loop. That is, they don’t modify the inputs ( economic activity and emissions output) that their outputs ( temp, sea level, disaster) insinuate. oh well, B+.

    Put another way. The climate science part of the System { F(emmissions) =warming; F(warming) = enviromental impact)} Is not an issue.

    the issue, the uncertainty lies in this.

    F(Enviromental impact)= economic activity.

    That’s missing. Now, you can prove to yourself that is is missing ( the feedback between climate output and econimic activity input) by witnessng the debate over the impact statement. You go ahead and object, I’ll explain.

    And you finish with this florish, you little ahab.

    “Remember the suggestion that the best economic approach to whaling was to liquidate the resource and put the money in the bank, because interest rates are higher on money than the rate of growth of whales.”

    No I don’t recall this, but economists and fishmongers say many stupid things. Oh hell, we all do. First, the probability of finding whales decreases with decreasing numbers of whales according to accepted search algorithm metrics and the cost function of finding them correspondingly increases with diminishing numbers of whales, dimisnishing thereby and consequently the cost basis of the investment and adversely impacting the overall ROI; so the strategy, while numerically sound in the abstract, is practically impractable in the concrete. Follow?. This Much like emitting all the C02 you can without facing consequences ( see A1F1). The A1F1 data sets say this: If you emit TWICE the C02 of the B2 scenario ( a green scenario) THEN, you will be twice as rich. Or if you’re twice as rich, you’ll spew twice the gas ( this is the Gore formulation of the rule) You will also be hotter ( around twice as hot.. near abouts) and nearly twice as wet..

    Let me put this all in another frame.
    the last 100 year average for sea level increase is 20CM; give r take. Eyeball that data out to 2100. Kentucky windage.
    “Errr. I don’t know earl. that’s like fancy Phd math. maybe Like another 20CM? ”

    Projections for for 2100.

    B2: 20 to 43 centimeter.
    A1F1: 26 to 59 cm.

    “round abouts there earl.” low end of the projection is round about 20 CM.. Goes up from there somewhats, iffin more ice melts”

    Now, what could happpen over the next hunert years or so. Could be an inflection point ahead earl. Could be that big old
    greenland melts. Why then, kentucky windage would be all wrong.

    “so, iffin greenland melts, them californi folks and new york city folks, will be under water?”

    Yes earl.

    “Hmm. Why them folks should move inland. Otherwise, they would be following the dodo bird to extinction. Ain’t they got no common sense. why a cockroach got more survial instinct than them.”

    Personally, I never extrapolated beyond the data without wearing a condom

  23. 273
    Steven Mosher says:

    Thanks Nick,

    I think the unrealistic scenarios continue to be evaluated because they make for sensational headlines. Apocalyptic scenarios and end of days tales that have the tendancy to push us into less democratic governance structures. You can’t trust yourself to do the right thing, therefore trust these people, this agency, this institution, to do the right thing.

    Witness the people who said humans don’t know what’s best for them.
    Kinda midevil. Kinda religious. Kinda pre enlightement. kinda elitist.

    But I have seen this of late in the half/hard sciences. in the hard sciences, we would just follow Popper. Make your prediction, see you in the lab tommorrow. Bring cash.

  24. 274
    Steven Mosher says:

    RE #269.

    ” Reading Jared Diamond’s “Collapse” doesn’t make one believe that people consistently are able to make good long-term decisions. Perhaps we know more now, but it is still clear that many people are able to ignore even strong evidence.”

    So, you read a book. You processed black marks on a page, and that made you believe something? WOW. Some people ignore strong evidence. Other people believe what they read. Go figure. There are times when ignoring strong evdence has adaptive value. There are times when jumping to conclusions has adpative value. Go figure.

    Now about this book and what you read. Did you test it? Nope. It’s historical analysis. Not science. You read it. You believed. Confirmation bias. Yes, you can find examples of people consistently making the wrong decisions.. short term or long term. Yes, someone will win the lottery. Sometimes, People go wrong by engaging in group think. By stifling voices that say something different. they listen to other people, who tell them they don’t know any better. They read bibles and history books that tell them the truth. So, yes, I suppose one can find examples through history of societies that have collapsed by channelling behavior and thought in very narrow ways. In some cases this channellng of behavior destroys the means of living.

    So, one could precipitate a societal collpase through the group think of “CUT EVERY TREE DOWN.. easter island” or one could freeze to death by the group think of “freeze rather than kill a tree”

    Then you wrote.

    “The AGW problem seems unusual, in that humans are just not used to dealing with causes whose lag-time to effects are decades/centuries. Many people think that AGW can’t be true because the temperature rise in the 20th century didn’t immediately track the CO2 buildup, i.e., they don’t understand the lag-times and inertia in the system ”

    Perhaps, attentiveness to problems with long time lags HAS NO ADAPTIVE VALUE. Put another way, preventing the eruption of the Yelowstone Caldera is a long term issue. The earth will be totally destroyed. But we are doing nothing about it.

    People see a generation or two ahead. That time scale for integrating and evalutating interest has had adaptive value.

  25. 275
    John Mashey says:

    re: #271
    Based on past inter- glacials (using Ruddiman: Plows, Plagues & Petroleum as an accessible reference):

    a) Without human civilization, glaciation seems likely to have restarted (Baffin island, Labrador) about 4,000-5,000 years ago [Ruddiman: Chapter 10], and almost got started during the later Little Ice Age [p.145].

    b) Hence, the natural course would be that (with the usual jiggles), sea level should already be lower, and going *down*, not up, right now. When we’ve used up most of the fossil fuels, the temperature will likely go down, and so will the sea level. In the meantime, given that we haven’t even seen the effects of the CO2 already out there, it will get hotter & higher sea levels for a wile, although I suppose we could lower the temperatures for a while, in some local areas, by encouraging sulfate-generating industry and accpeting really intense acid rain…

    Nevertheless, it seems that the likely next few hundred years is the equivalent of:

    a) In summer, turning the thermostat as high as possible, and searching hard to buy as much energy as possible to heat it even more, rather than saving it.
    b) And then, in winter, discovering energy is expensive, because it’s been used up.

    For most people, that’s a completely backward way to run a home’s thermostat, but some people seem to be urging that we run the plant’s thermostat that way :-)

  26. 276
    Steven Mosher says:

    RE 269.

    The reason I love historical analysis is you can always find a contrary opinion. Like I said. CONFIMRATION BIAS. I read this book. It confirms we are ecological monsters. Therefore, since I believe we are, I believe it more now. And you should too.

    Here is a cite of a different explaination of easter island. Damned rats and europeans

    http://www.livescience.com/history/060309_easter_island.html

    Now the debate over appeals to authority would be engaged.

  27. 277
    Gareth says:

    I think the unrealistic scenarios continue to be evaluated because they make for sensational headlines. Apocalyptic scenarios and end of days tales that have the tendancy to push us into less democratic governance structures. You can’t trust yourself to do the right thing, therefore trust these people, this agency, this institution, to do the right thing.

    You are over-interpreting what the scenarios are for. They exist as a means of asking “what if?” questions. It doesn’t matter that some are intrinsically more likely (or feasible) than others. The object is to generate emissions trajectories to drive GCMs to allow us to evaluate the climate system’s transient response at different greenhouse gas levels. They have served that purpose well. They have never been a policy-relevant tool.

    The challenge over coming years is going to be move from “what if?” to “how?”. We need to work out how we can reduce emissions so as to avoid damaging climate change (so far as that is possible). The modelling exercises will then be more subtle – answering questions about global and regional climate at GHG levels corresponding to various policy options. This work is already being done, and is directly policy relevant.

    Meanwhile, climate modellers will continue to refine their models. As we get a better idea about the scale of, for example, ice sheet melting or carbon-cycle feedbacks, and a better idea of regional-scale changes, so we will be able to adjust our mitigation targets and improve adaptation strategies.

    Your view of what the best policy response will be coloured by your political outlook, but the evidence will not be.

  28. 278
  29. 279
    Nick Gotts says:

    RE #268 You have a valid point Ray, and I’m certainly not confident that the right decisions will be made in time, but the shift over the last year has been greater than I’d imagined possible – in the US as much as anywhere. You mention the Russian-Chinese-Saudi sabotage on the IPCC SPM, which is certainly disappointing, but raises a number of points:
    1) Everyone interested knows about it, and most know that this is nothing to do with the science. I hardly think even the denialists are going to be boasting about how they have the support of these three regimes.
    2) All three of the saboteur governments are profoundly undemocratic. A year or two ago you’d have found the US and Australian governments in there with them – now they don’t dare.
    3) I’ve suggested that a sufficient consensus for real action could be built by a relatively small number of governments (meaning, rather than through the IPCC). An initial agreement could certainly do without Saudi Arabia, and even Russia – as primary fossil fuel producers, they would just have to lump it if consumer countries reduced demand. China looks an essential partner, but I think its regime is likely to want to be included in such an initial agreement; and would be very vulnerable to “GHG tariffs” on its exports. The trick may be to make such inclusion a matter of being recognised as a first-rank state.

    Re #273. Steven, I said you had a point. Not that I agree with your overall viewpoint, which appears both incoherent (it would help us all if you stated, in a straightforward way, how you think both science and policy should proceed from where we are now, but I suspect you won’t and indeed can’t do anything of the kind), and condescending towards anyone who disagrees with you. It made perfectly good sense for modellers to concentrate first on the physical science, in order to tell us, as far as possible, the climatic effects of putting certain amounts of GHGs into the atmosphere on a certain schedule. It’s once we turn from the scale of the problem to the search for solutions that we need to incorporate feedbacks from human responses to both actual and anticipated change. In my view, we’re now at or near that point, although of course refinement of the physical science models should continue.

  30. 280
    Jeffrey Davis says:

    re: 271

    Liquid falling from the sky can be natural (rain, sleet, snow) or it can be someone emptying a slop jar (you don’t want to know).

    You’re employing a rhetorical/logical wowzer by trying to shoe horn all possibilities under a single umbrella.

  31. 281
    John L. McCormick says:

    RE #271

    Louis, you said:

    [Instead of worrying about what causes sea level change and how to stop it, (because WE CAN"T!), we should figure out how to manage it and live with it.]

    I suggest you put down your sea level rise stove pipe and look through the ocean acidification stove pipe. Long term, not something we can manage and live with.

    Then pick up your melting glaciers stove pipe (particularly the Himalayan glacier metlback stove pipe. Frightening thought — nearly a half billion people will have to find another source of irrigation and drinking water.

    Now, grab the permafrost and tundra melting stove pipe. See the increasing outflow of carbon dioxide and methane being released to the atmosphere and making the darned problem even worse.

    Louis, read a bit more than the newspaper accounts of the IPPC estimates of sea level rise and you will learn there are many facets to this AGW problem. Some will bite harder than others and may well be consequences we cannot [figure out how to manage and live with]

  32. 282
    Carrick says:

    Stefan, thanks for your thoughtful insights.

    My personal objection to the discussion of the threat of sea level rise is the opposite of yours, namely that the threat of near term sea level rise is nearly always overinflated.

    For example, on Friday’s Science Friday, Ira Flatow made a comment (paraphrased) “if the East Coast is submerged in 100 years…” There were three guests there, I suppose all experts on climate change, and not one jumped in say that this is an extremely remote possibility not supported by any climate model. That adds nothing to the credibility and perception of objectivity of any of the guests present.

    Too much of the dialog on both sides is self-serving for either side of the debate to make any claim of moral high ground, in my humble opinion.

    And what’s with quotes on “skeptic”? Anybody who questions the veracity of your arguments has to have an ulterior motive? This distracts from your otherwise strong arguments by making you look as agendized as you claim the skeptics to be.

  33. 283
    James says:

    Re #273: [Witness the people who said humans don't know what's best for them.]

    So here I am, one human forced by the realities of nature to share the planet with six billion or so others, a good many of whom seem bent on rendering the Earth, if not completely uninhabitable, at least a far less pleasant place for me to live. I don’t claim to know what’s best for the rest of those six billion humans: I just want to live my own life unmolested by their byproducts. When I advocate CO2 reductions, or any other environmental action, it’s not altruism that motivates me, it’s self defense.

    It seems to me that you’ve adopted the collectivist point of view, arguing as though “humans” or “the people” were a singular entity, then urging me to adopt a sort of indulgent altruism and subordinate my own needs and desires to the gratification of the masses. This is not an argument that appeals to me at all.

  34. 284

    [[For example, on Friday's Science Friday, Ira Flatow made a comment (paraphrased) "if the East Coast is submerged in 100 years..." There were three guests there, I suppose all experts on climate change, and not one jumped in say that this is an extremely remote possibility not supported by any climate model. That adds nothing to the credibility and perception of objectivity of any of the guests present.]]

    Recent evidence is that the dynamics of ice sheet movement in times of warming may be strongly non-linear. That’s why the climatologists didn’t jump on the host. If things go badly enough, New York and Miami really could be underwater in 100 years. At this point, we don’t know how likely or unlikely that is. Things are happening in Greenland and Antarctica that nobody predicted, and until we understand what’s going on there, all bets are off.

  35. 285
    steven mosher says:

    Thanks gareth.

    I’ll be quick and to the point. You wrote.

    “You are over-interpreting what the scenarios are for. They exist as a means of asking “what if?” questions. It doesn’t matter that some are intrinsically more likely (or feasible) than others. The object is to generate emissions trajectories to drive GCMs to allow us to evaluate the climate system’s transient response at different greenhouse gas levels. They have served that purpose well. They have never been a policy-relevant tool.”

    since the scenarios drive the boundaries of the estimates ( for example .59 M in the A1F1 case) then assumming a uniform probably of occurance for the scnearios does matter. Since a .59M increase in sea level will impose a cost, one should like to know the probablity of occurance to constrcut an appropriate cost/benefit fucntion. If the sea rises 20 CM over the next century as it did in the last. Then costs will be X. I would suppose 59CM would be more. Does it make sense to abate this potential outcome?

    You continued:

    “The challenge over coming years is going to be move from “what if?” to “how?”. We need to work out how we can reduce emissions so as to avoid damaging climate change (so far as that is possible). The modelling exercises will then be more subtle – answering questions about global and regional climate at GHG levels corresponding to various policy options. This work is already being done, and is directly policy relevant.”

    The issue I raise is the opposite. Scenarios that show low emisions are impoverished. Scenarios for high emissions are wealthy. Hot looks good. Also, note how you assume that climate change is bad. How can we reduced emmissions to avoid damaging the climate? damage? see the coloring of your observations. You think change is bad. Maybe its good? Maybe change is just change. Why valorize the state we are in? The climate will change. Man will impact his enviroment. These changes will impact man. We will change. I’ve never understood why generations of people who are brought up and taught the truth of darwin, suddenly forget this stuff.

    Let me put this another way. What is the cost of climate change?
    EPA documents suggest that a 1 meter rise in sea level would only cost the country 250B over the next hunderd years. Not a risk that requires global action in some peoples opinion. 250B is peanuts over 100 years. Hint: don’t rebuild new orleans under water. look ahead! no climate model required there. hey, you got gills? No? then don’t build your house below sea level sponge bob!. Sheesh. But no. we will tax your carbon, so that guys without gills can build their houses below sea level.

    And you finish..

    “Meanwhile, climate modellers will continue to refine their models. As we get a better idea about the scale of, for example, ice sheet melting or carbon-cycle feedbacks, and a better idea of regional-scale changes, so we will be able to adjust our mitigation targets and improve adaptation strategies.”

    Do you see the bias here? MITIGATION? why would you assume that hotter is worse off? why? Look at temp growth in the past 100 years. Look at the growth of wealth. Just look. Observe. Hotter and richer. Now, given that the historical data shows that the more C02 you put out the higher your GDP, ( why else are we scared of china and india output) what evidence driven, fact driven, hypothesis testing, rational being would assume the opposite. Do you want to be poor? I would say the data suggests we should burn more not less. I mean just look at the evidence.

    The evidence should not be colored by your outlook.

    And you conclude:

    “Your view of what the best policy response will be coloured by your political outlook, but the evidence will not be.”

    I’ll give you a reading list. Then we can have a fun discussion. Quine. Popper. Jerome Bruner. Thomas Kuhn. That’s a good start.

    Your view of the evidence can be colored by your outlook. Witness the nutjobs who talk about the Gore effect.

  36. 286
    David B. Benson says:

    Re #285: steven mosher — You have left out anything regarding biology. Roughly speaking, hot is bad. Now a with a slow change, over many millennia, hot is ok. But many biological organisms cannot quickly adjust to the heat. Let’s see, just last summer, tens of thousands of cows died in the U.S. Do you know what happened a few summers ago in France?

  37. 287
    Michael says:

    … and a trigger point has been reached at which photochemical structures in plants change. Over past months, the nature and level of sugars in grass has changed and animals, such as horses, susceptible to enhanced sugar levels (giving equine laminitis) are suffering. The level of equine laminitis, resulting in a most painful death as hooves twist off, is going through the roof around where I live. It is just one example.

    More generally, take a look at bedrock maps, soil maps, and species maps. Study them carefully. In many cases there are strong links between surface-living species, soil structures and the bedrock geology. As the climate at the top of the stack changes, species cannot just shift en masse, because of the deep connections. Multiple wipe-outs are a consequence because so much is tied in an intricate delicate web. It is a web that we have so taken for granted.

    Hot is bad. We must do everything we can as fast as we can to reverse the terrible situation we have created.

  38. 288
    steven mosher says:

    Hi Nick,

    Thanks for engaging. Let me see if I can respond to your comments.

    “Re #273. Steven, I said you had a point. Not that I agree with your overall viewpoint, which appears both incoherent (it would help us all if you stated, in a straightforward way, how you think both science and policy should proceed from where we are now, but I suspect you won’t and indeed can’t do anything of the kind), ”

    Ok, My overall viewpoint is this. Economic assumptions ( fuel choices, land use, mitigation strategies) and population assumptions drive the emissions scenarios. The emission scenarios drive the climate outputs. climate outputs will impact economic activity. But in the current modelling approach, they do not. I don’t question the climate science. My issue is two fold. 1: the use of input scenarios that may drive boundary estimates in unrealistic ways. namely, A1F1. and two. The lack of coupling ( climate output to economic actvity) in a system that we all know is coupled, otherwise if changing the enviroment didnt change our way of life why would we be worried about change?

    So, I would think that the science should proceed in the following way.
    Instead of working with a 100 year data set, with input parameters that vary by almost an order of magantude. look at 30 year datasets.take the outputs. Feed these to the scenario writing teams, refine the inputs. Run another 30 years. Repeat rinse etc. My sense is you would see a narrowing of the error bounds. Certain “green” scenarios are unrealistic. Other doomsday scenarios where we burn everything are unrealistic. And we will end up with an estimate that is something like
    1-3C warming.

    Policy wise;

    When the estimates are suitably constrained we can convince people to make changes that make sense from a cost benefit standpoint. I’ll reference something Noted earlier. In one EPA paper the cost of abating a 1M rise in sea level in the next 100 years.. is on the order of 250 B. Looking at the past increase of 20CM over 100 years, and estimates for the future,I can see planning for and funding this abatement. You live in a coastal region. Here’s your new tax assesment. You buy a property that could be inudated in the next 100 years, you pay into the risk fund. basically tie consequences to behavior. This lets mr darwin operate.

    On the other hand, when we have a prediction that is “how shall I say” very non linear. As in 7M over the next 100 years, because of a catostrophic event, then we have a harder time, 1:evaluating that risk and 2: selling the abatement of that risk. Its like buying insurance for losing an arm or leg.

    The other point here is how we allocate resources. Do we allocate more resources to study this potental catostrophe? or money to study tree rings? I’d opt for the former. I’d buy insurance against the most likely outcomes ( measuring of course the cost of prevention against the cost of remediation) and I’d focus research on the low probablity high cost outcomes ( like greenland melting) since the expected value of those outcomes may be high. I would not, willy nilly, simply impose a carbon tax or carbon trading scheme. Witness the EU mess with that.
    Ah yes, they will get it right second time around.

    You continue:

    “and condescending towards anyone who disagrees with you. It made perfectly good sense for modellers to concentrate first on the physical science, in order to tell us, as far as possible, the climatic effects of putting certain amounts of GHGs into the atmosphere on a certain schedule. It’s once we turn from the scale of the problem to the search for solutions that we need to incorporate feedbacks from human responses to both actual and anticipated change. ”

    Yes, I agreed condescending was bad form. And I understand fully the need to excercise models at the limits. However, there is a danger of blowback. One could, as I did, look at the scenarios and conclude. hey, this A1F1 world is prety good. 500 Trillion GDP! and its only a few degrees hotter. compare that with a B1 or B2 world. You’d pick a fossil fuel future. So, I don’t think people can step back and say ” hey I’m just running the data” Seriously, you know if you ran a model, that you excercised it with a 2Xc02, 3X, etc etc commitment scenario, etc etc, before the new SRES ever came out. The real focus was probably on matching history and coordination with other models. In all seriousness, you do not believe that the A scenarios are equally likely as the B scenarios. Maybe you do. I don’t.

    Any you conclude

    “In my view, we’re now at or near that point, although of course refinement of the physical science models should continue. ”

    Here is what I saw. With close to 20 models running in a coordinated manner the error band for any given scenario ( say b1) was probably about as tight as it needed to be for Policy. Just eyeballing the chart in the summary report it looks like +-.5 c or so. Now, the bigger variation is BETWEEN scenario. You tell me. When you have one projection for the future that assume 5Gt per year and another that assumes 35Gt.. where would you look to refine your understanding.

    That’s right. If you wanted to maximize a research dollar you will get more bang from the buck if it spent on SRES refinement rather than climate science. Simply, spend money on areas of high uncertainity that relate to high high costs. Study ice and economics.

  39. 289
    Adrianne says:

    I am glad that the oceans are finally getting the attention they deserve, as it was time to stop discussing car emissions and talk about the really important factors in the climate change process.
    You may have read my previos comments, and know by know that I don’t agree to many points of the IPCC report, because I consider it being superficial. To give you a reason, this is a letter that I read and that I think expresses well what I feel about the report.

  40. 290
    John Mashey says:

    re: #289:
    “And what’s with quotes on “skeptic”?”

    The problem is some fuzziness in the use of English:

    1) SKEPTIC: To me, the terms “skeptic” and “skeptical thinking” have usually meant someone takes nothing on blind faith, examines alternate viewpoints carefully, weighs evidence, and changes their mind when new data arrives. I think those are good things. Of course, if you look it up in various dictionaries, you find various meanings.

    I’ve known lots of good scientists, and they generally work this way, and are mostly perfectly happy with real skeptics. I’m always happy to have a few well-informed skeptics poking at mainline theories, since sometimes advances come from studying inconsistencies. Occasionally, really wacko-sounding ideas work out.

    2)CERTAINTY: However, some people have been 100% sure (often in temporal order) that:
    - there is no warming, temperatures jiggle naturally anyway, and scientists don’t understand any of this
    - well, satellites disagree with with ground stations
    - well, maybe there is warming, but it’s not caused by humans
    - well, if some of the warming is caused by humans, we don’t know how much
    - well, if there is warming, it’s caused by {changes in Sun, cosmic rays, etc},and besides the Mars polar cap is melting, so it’s nothing to do with humans.
    - well, we can propose mechanisms that might cancel the warming.
    - well, even if there is AGW, we can’t do anything about it, so we shouldn’t try, people should just migrate away from the coasts.
    - well, we aren’t 100% certain, so we should study it more.
    - well, under no circumstances should we damage our economy by conserving energy [i.e., we should never be so silly as to act like California, which is relatively energy efficient, and whose economy must therefore be just awful. (The Wall Street Journal editorial page regularly mocks CA for such activities, even as the news sections applaud CA business. :-)]

    The problem is, such a view is “skeptical” of AGW, but many people have trouble according it the positives of the classical skeptic in 1), and hence write “skeptic” or sometimes *denialist*. In my experience, good climate scientists are happy to answer questions from real skeptics [RC is a fine example], but rightfully get weary of denialists.

    3) SKEPTICAL THINKING For instance, a *real* skeptical thinker might want to do the following: do as I did in 2002-2003, averaging an hour a day across several years. It would take much less time now, because there’s a lot more data, and some of the annoying inconsistencies have evaporated, and some of the lingering questions now have plausible hypotheses to help explain them, and there are good websites like RC. Here’s what I did then (and for background, my undergrad work was math+physics, followed by MS/PhD in computer science, and I’m a AAAS member, so I’m fairly comfortable looking at primary research articles when needed. I’m certainly not part of any climate-science establishment, although I used to help design supercomputers used by such people.)

    a) Read books by mainstream scientists, such as the IPCC books, several of Stephen Schneider’s, John Houghton’s “Global Warming”, Mackay et al “Global Change in the Holocene”, Krauskopf & Bird, “Introduction to Geochemistry”, etc. If someone were starting now, Ruddiman’s Plows, Plagues, and Petroleum” is my favorite, especially if one doesn’t have a technical background.

    Read Science (or Nature) every week.
    Join the AGU for a while to see what else the professionals are doing.

    b) Get a few alarmist books, like Berger’s “Beating the Heat” (which irked me by lamenting the future disappearance of penguins from the Arctic.)

    c) On the other side, read Lomborg’s “Skeptical Environmentalist”; Fred Singer’s “Hot talk Cold Science”, Essex & McKitrick’s “Taken by Storm”, etc.

    d) Follow ongoing discussions, websites, Look at NOAA, USHCN, etc to understand measurements. I also watched John Daly’s website, and CO2science, and GreeningEarthSociety, etc, etc. I followed the McIntyre & McKitrick papers, and later (2006) studied the Wegman Report.

    e) Keep a list of outstanding objections to AGW. When appropriate, backtrack references to primary research papers. Watch how the list changes with time,and how it relates to ongoing research.

    f) When possible, interact with real climate scientists. I had the fun of being the “skeptical discussant” for a (very good) Stephen Schneider seminar at Stanford: I brought in my current stack of booksd, asked a few tough questions, and asked what else I should look at. He explicitly had no problem with someone questioning AGW, if they were doing it rationally, rather than reflexively. His talk carefully discussed degrees of uncertainty, and if he was upset at anyone, it was at those were 100% sure that AGW didn’t exist, not at those who approached AGW as classical skeptics.

    g) MOST IMPORTANT, and the reason one can’t do this overnight: to understand the science and (necessarily) politics of a theory like AGW, you need to track it for several years, especially to calibrate the players. If you study history of science:

    - a new hypothesis appears, which of course must at least be consistent with existing data, and preferably makes further predictions that can be tested, and preferably, is as simple as possible, but no more.

    - as new data arrives, the hypothesis might be rapidly disconfirmed, or it might need to be adjusted (Ruddiman gives a good example in PPP: Chapter 11).

    - there is *always* ambiguous or contradictory or missing data.

    For a hypothesis to become a well-accepted theory:
    + new data tends to confirm it
    + ambiguities tend to get narrowed
    + contradictions tend to get resolved

    BUT, you have to watch it for a while to see that happening.

    Over time, better theories tend to be better approximations of reality, but even great theories (like Relativity or Quantum Mechanics) don’t explain *everything* – legions of physicists have labored mightily for decades to create a theory that subsumes both of them, but in the meantime, GPS satellites work and so do transistors, even in the absence of an all-encompassing theory.

    Scientists, being human, sometimes defend their data and hypotheses like a lioness defends her cubs, but most are careful to calibrate the quality of data and areas of uncertainty, with numerous caveats, and most change their minds as data accumulates. This puts them at great debating disadvantage with people who have always been 100% sure that AGW doesn’t exist, especially in a sound-byte era.

    4) AGW After watching all this for a few years, my opinion got increasingly firm:

    - In the early 1990s, there had been plenty of room for uncertainty about AGW (not about the basic physics, of course), but there were more loose ends, temperature jiggles for which the explanations were more uncertain. It seemed to me that there were alarmist views that were premature, but:

    - Over time, data piled up overpoweringly, contradictions (like satellites vs ground stations) got resolved… etc. I’m used to science: there are always measurement errors, and one would always like more data, and yes, clouds and aerosols are not perfectly understood, but That’s Life.

    - This left very little room for doubt of the basic AGW theory, if one actually studied the science, and especially if one had even modest technical background. I was pretty clear that mainline scientists were not being alarmists, but had pretty good reasons for saying what they were saying.

    - Occasionally, I was uncomfortable with the ways summarization happened, and data presented graphically. Specifically MBH98+MBH99 (well-caveated) -> IPCC TAR main report -> IPCC TAR TS -> IPCC SPM
    (whose specific hockey-stick chart with gray error zone had to be unconsciously misleading for the intended audience, which I’d guess is unlikely to think much about error bars and uncertainty.) I was sensitive to this because of long-running similar issues in my own discipline (computer science, especially performance characterization, which often tries to be overly precise to make things simple.)

    I always thought that was an unfortunate evolution, which started with studies heroically trying to extract signal from difficult historical data, with appropriate caveats, but emerged looking like everyone was really sure of one line, even though that certainty was clearly not true when one back-tracked through the eventual layers of proper caveats. It’s too bad IPCC didn’t think of a better way to present that data, but I sympathize with people who do understand uncertainty arguing with people who are always 100% sure.

    I thought that it really didn’t matter whether the current temperature was slightly above or slightly below the peak of the MWP. What mattered to me was that the temperature was going up fast, that the lag time effects meant it would keep going up for many decades, no matter what, and that there were at least 10X more people on the planet now. Having grown up on a small farm, I heard about “carrying capacity” before I was 10.

    5) “SKEPTICS” It also became clear was that there existed a relatively small number of vocal people and organizations, who were not acting like classic skeptics, but had the clear point of view described in 2), apparently arising mostly from other-than-scientific concerns:
    - specific political or ideological beliefs
    - economics
    “It’s hard to convince someone if their livelihood depends on not believing.”

    Certain tactics became apparent, a lot like those used to obfuscate research on smoking-cancer link (unsurprising: some of the same people/organizations, but funded by ExxonMobil rather than RJ Reynolds Tobacco).

    -Arguments were made via whitepapers, web pages, OpEd pieces, not peer-reviewed research.

    -Old, long-debunked claims were cited over and over.

    -New data was ignored.

    -Completely irrelevant claims were thrown up (Mars!)

    -Sham polls were produced. [I might be interested in a real poll by AGU or AAAS of their members who are practicing climate scientists. "Polls" like OSMI's: no way.]

    -Claims of major scientific controversy, based almost always on the opinions (but not usually peer-reviewed) of a minuscule handful of scientists, of whom only a few were actually climate scientists. Scientists are always always arguing about details, but I sure couldn’t find major controversy, just normal observational science in progress.

    -Claims that some paper contradicted AGW, but when I’d go read the primary research journal, it wasn’t true.

    -There was constant cherry-picking of data [like saying the Wegman Report was a refutation of AGW (it wasn't), like picking a few weather stations showing downward trends, like saying there was no sea-level rise by citing Stockholm's sea-level records. A random layperson might be forgiven Stockholm, but not a professional oceanic meteorologist, who couldn't possibly be unaware of Post Glacial Rebound (PGR).]

    -In general, the arguments seemed directed to keep the public confused, as opposed to contributing to science. That is, it would be plausible for someone to propose a testable, alternate hypothesis that explained the existing data, but this wasn’t that, this was “anything but AGW”. The closest I could find that looked like a serious hypothesis was Lindzen’s IRIS hypothesis, which remains up in the air, at best, and in any case, is more of a claim of a mechanism that could automatically ameliorate AGW.

    It is quite easy for people who haven’t studied this in detail to pick up denialist ideas, because they are usually packaged as simple sound-bytes that are easy to remember. There may be masses of real science that refutes them, but the latter do not lend themselves to quick simplicity. I’m actually surprised that climate scientists are as patient as many are, giventhat they’ve had to deal with this for years.

    Anyway, over time (and it takes a while, because a snapshot at any onetime doesn’t capture the dynamic behavior), it became clear that the underlying position:

    (“under no circumstances conserve fossil fuels or regulate CO2″)

    was the constant, and that there were a continuing (but ever-changing) series of ideas thrown up against AGW, not with the idea of improving scientific models to better approximate reality, but in support of particular political/economic views, using tactics to keep the public as confused as long as possible. (And it’s OK with me to promote one’s views … but I’d rather it be done by being upfront, not by obfuscating science.) Such tactics can work fairly well, as they did for RJ Reynolds (it took a long time to restrict smoking, didn’t it?) It is totally unsurprising that trying to mitigate AGW (especially by conservations) is simply not in the short-term interests of some companies, just as restricting smoking is not in RJR’s.

    6) CONCLUSION So, I started from a classical skeptic viewpoint, studied the problem in fair depth (for a non-climate scientist), and got convinced that the AGW science was quite solid, notwithstanding some occasional problems in graphics/statistics presentation akin to ones I’ve seen in my own discipline).

    I also got convinced that there was a small, but vocal group who were *not* skeptics, but “skeptics” or denialists. I don’t think that real climate scientists have a problem with classical skeptics, just with 100%-sure denialists calling themselves skeptics.

  41. 291
    Gareth says:

    Re #285 Mosher:

    As someone else has pointed out, you ignore or drastically underestimate the impacts of warming. If you are so keen to hand out reading lists, then I will respond with only one: start with the Summary For Policymakers of the IPCC’s WG2 report (available here), then move on to the full report when it’s out in May. With luck you might change your tune. But I won’t be holding my breath.

  42. 292

    [[I am glad that the oceans are finally getting the attention they deserve, as it was time to stop discussing car emissions and talk about the really important factors in the climate change process.]]

    Adrianne, the oceans emit about 90 gigatons of carbon per year, but they take in about 92. They’re a net sink for CO2, not a source of it.

  43. 293
    Nick Gotts says:

    Re #288
    Thanks Steven, you confounded my expectations. I’ll reply in full when I’ve had time to give your post the consideration due.

  44. 294
    Adrianne says:

    RE #290, A marvellous piece of elaboration on â??skepticâ?? you kindly brought to my attention. Cordial thanks!

    I should have presumably more straight, and should have put it as follows: In 2004 Bengtsson et.al., said that the Arctic 1920-1940 warming is one of the most puzzling climate anomalies of the 20th Century, assuming that this was probably a result of the influx of warmer water into the Barents Sea, resulting from a short-lived change in wind patterns.

    That makes me sceptical for the following reason: Already 1936 Scherhag asserted as a reason for Spitsbergen warming after WWI had ended an increase of atmospheric circulation, to which C.E.P. Brooks (1938) made the correct diagnosis, that this pushes the problem one stage further back, for one should still have to account for the change in circulation. All reference on the link previously given, respectively here.

    Hopefully we do understand better now:).
    Best regards,
    Adrianne

  45. 295
    James says:

    Re #288: [One could, as I did, look at the scenarios and conclude. hey, this A1F1 world is prety good. 500 Trillion GDP!]

    Do you suppose GDP might be an overly simplistic measure of well-being? How is a $500 trillion GDP better than a $250T one, if the $500T has to spend half (or more) to cover additional costs arising from the higher GDP?

    Or for a personal example, I once worked in Switzerland. The pay was about half again what I might expect in the US, but the cost of living was nearly double. Did having a higher income mean that my standard of living, my basic well-being, was higher? Of course not, and neither does just a simple comparison of GDP numbers provide a useful measure of quality of life.

  46. 296
    mark s says:

    RE #290,
    excellent post, John, thanks.

    RE #285,
    Steven, i don’t think you should suggest further reading for others (#285), given your attitude to other posters reading, as displayed in #274.

    “So, you’ve read a book…WOW…You read it. You believed. Confirmation bias.”

    You clearly haven’t read “Collapse: How societies choose to fail or survive”. I’m glad to say i have, because its a good book, tho maybe not as good as the Pulitzer Prize winning “Guns,Germs and Steel”, Diamond’s first book.

    If you had read it, you would know that mankind is not portrayed as an “ecological monster” (from your post #276), very far from it. In fact Diamond is reasonably positive about mankinds future, and gives numerous examples of successes, as well as failures.

    So who is displaying confirmation bias here, I wonder? Hoist by your own petard, i fear.

  47. 297
    James says:

    Re #286: [...Now, given that the historical data shows that the more C02 you put out the higher your GDP...]

    I think you’ve allowed a fundamental misconception into your reasoning there. The causative relation is much more accurately between energy use and GDP. Of course if you look at the GDP of a country that historically gets a certain fraction of energy from fossil fuels, then of course CO2 rises as a consequence of increased energy use, but the correlation is just due to technology choice.

    If you look across countries, you’ll see some that for various reasons have a lower percentage of fossil fuel in their energy mix. Here’s a link to a table of per-capita CO2 for European countries for the year 2002:

    http://www.dataranking.com/table.cgi?LG=e&TP=ee02-1&RG=3

    Now I think we can agree that Switzerland is pretty close to the head of a per-capita GDP list, no? Yet it is quite far down the CO2 list. Why? Because it gets much of its electricty from hydropower, and runs a good bit of the transport sector on it as well. (Trains and most urban streetcars/buses are electric.) France is another such case: since it gets a large fraction of its electricity from nuclear power, it’s well up the GDP list (despite internal problems) while staying low on the CO2 list.

    Thus there’s no inherent contradiction between CO2 reduction and economic growth. Just start thinking outside the energy == fossil fuel box.

  48. 298
    Simon says:

    Hey, here’s a story about this guy who’s a big-time Global Warming denier; you should read it and post some comments for him to know what we think about his ideas.”

    The link: “Global Warming Is The Biggest Tale Ever Told to Humanity” http://www.orato.com/node/2160

    [Response: "This guy" is non other than Tim Ball. - mike]

  49. 299
    Blair Dowden says:

    And the content of this story is pathetic: a slight cooling between 1940-1970, climate models are not perfect, carbon dioxide is not a poison, dumping iron filings in the ocean to reduce carbon dioxide is a bad idea. Even by the usual (low) denialist standards, this is rather feeble stuff. I find it shocking that someone trained as a scientist could write such drivel.

  50. 300
    Hank Roberts says:

    Simon is pointing us to a story on his own website (orato is linked both to Simon’s signature and to the “this guy” story). So Simon certainly knows who “this guy” is. Just asking for attention by asking for people to tell “this guy” “what we think” about his ideas, I’d bet, for pagerank?
    Curious “news” site. “Seal Hunting is My Life” is reminiscent of “CO2 is Life.”


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