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Full IPCC AR4 report now available

Filed under: — group @ 29 April 2007

The complete WG1 IPCC 4th Assessment report (AR4) is now available online. It’s missing the index and some supplemental data, but all should be available by May 7.

Over the next few weeks we’ll try and go through the report chapter by chapter, but since this is likely to the key reference for a number of years, we can take a little time to do it properly. Happy reading!


205 Responses to “Full IPCC AR4 report now available”

  1. 151
    Ray Ladbury says:

    Rod,
    As I said above, the significance of the “cooling” depends on which metric you look at. The meteorological stations show it more than the land-ocean metric. Even with the meteorological stations it is hard to know whether what you are looking at is anomalously high warming in the late ’30s and early ’40s, followed by a single fairly dramatic drop until 1950 and flat trends from 1950-1975. Note that all of the data are consistent with an aerosol driven cooling due to burning of fossil fuels. I’m afraid I agree with Tamino: It is a very different thing to say that 1970 was cooler than 1944 than it is to say there was a 30 year cooling trend. The latter is simply no supported by any reasonable analysis of the graph. Climateaudit and others are guilty of graphsmanship at the very least. In any case, this is all a red herring. I don’t know of anyone who disputes that we are warming significantly now–at least not anyone I’d let play with a sharp object.

    Re 145. L.R. Please. Now, we’re going to get into the whole “climate doesn’t exist” argument. Climate concerns persistent trends in weather. If it were not a valid concept, then agriculture would not be possible. What you are engaged in is pure sophistry and spin. Climate exists and we are changing it.

  2. 152

    Re 145 and 150

    Climate has two meanings. It can mean a set of statistics when applied to new York, say. In other words you can talk about the climate of New York, and that is a set of averages of temperature, humidity, atmospheric pressure and precipitation.

    But there is also a climate system which consists of winds, sources and sinks of water vapour, ocean currents and effects from mountains and rivers. It also includes El Ninos, hurricanes, and droughts. When we talk about climate change, we should really be using the term climate system change. Although it is too late to alter that now, people should be aware that word ‘climate’ has two distinct meanings.

  3. 153
    Rod B. says:

    re 141 (James): a minor but fun point: we’ll all burn up in the Sun’s Red Giant stage long before it becomes a White Dwarf. Now there will be a global warming with unanimous consensus!

  4. 154
    Ray Ladbury says:

    Re 153.
    Rod B. wrote: “re 141 (James): a minor but fun point: we’ll all burn up in the Sun’s Red Giant stage long before it becomes a White Dwarf. Now there will be a global warming with unanimous consensus! ”
    Actually, I think Lindzen will be holding out to the evaporation of his last carbon atom–at least as long as there’s a microphone nearby.

  5. 155
    tamino says:

    Well, I thought we’d beaten the horse until it was thoroughly dead. But it rears its ugly head…

    Re: #140 (Rod B.)

    But, and I hate to break it to you, if the temperature drops, IT’S COOLING!

    Suppose you win the lottery, and in one day your net worth increases from, say, $50,000 to $20,000,000. Over the next ten years, you invest 5 million in a fly-by-night company which goes bankrupt, donate 5 million to Oprah’s campaign to help children in Africa, and lose $9,949,999 gambling in Las Vegas. You’re left with $50,001.

    You complain about it to a friend, but he consoles you by saying, “Your net worth is more than what it was when you started — You’ve been getting richer for ten years!”

    Re: #146 (Caz)

    Using your criteria we haven’t had 3 decades of warming then. we’ve just had some warming – some cooling – some more warming and according to HadCrut (and RSS and UAH satellite) a more or less flat trend in the last decade.

    You haven’t run the numbers, have you?

    Nobody disputes that there’s natural variation in temperature. That’s what all the wiggles are about in the temperature graph. But those wiggles represent random fluctuations. It’s like flipping a coin and counting how many “heads” turn up for each ten flips. We expect 5 out of every 10, but that’s not what we observe. We see ups and downs, more or less — but over the long haul, it averages to 5 out of 10 (unless the coin is rigged).

    If we want to know which wiggles/changes are genuine trends rather than random fluctuation, we apply statistics.

    When we do so to the temperature time series, the theory “cooling from 1940 to 1970″ doesn’t even pass the most basic significance testing. And there’s plenty of data during such a long time period, so we can rule that out. The hypothesis “cooling from 1944 to 1951, followed by stasis from 1951 to 1975″ gives a strongly significant result. In fact, of all the hypotheses I’m aware of, this one gives the most significant result.

    For the last three decades, the statistically strongest hypothesis is “continuous warming,” while your “some warming – some cooling – some more warming and a more or less flat trend in the last decade” theory does not pass muster. Not even close.

    As a matter of fact, if you take only the data from 2000 to the present, you still get a statistically significant warming. The same is true for 1999 to the present, or 1998 to the present, or 1997 to the present, or … you get the idea.

    One last note: the latest corrections to the RSS and UAH satellite temperature data bring them into agreement with the surface temperature record and the computer model results for the lower troposphere. So, you’re wrong on all counts.

    Re: #141 (P. Lewis)

    If the temperature is warmer in 1969 than it was in 1939, we kinda think …

    Exactly. Both arguments are equally invalid — and this is a nice illustration of why.

    and: #150 (Ray Ladbury)

    It is a very different thing to say that 1970 was cooler than 1944 than it is to say there was a 30 year cooling trend.

    And that’s my point. For years now, we’ve been allowing this misrepresentation to persist. Let’s stop doing that.

  6. 156
    Ray Ladbury says:

    Actually, the discussion between Rod and Tamino about whether cooling and flat trending constitutes cooling over the period reminds me a little of the Monty Python logician’s routine from the album of Monty Python and the Holy Grail. It takes place just after Sir Bedevere proves a woman is a witch by showing she weighs the same as a duck. It is not long, so I produce it here in all its glory:

    The sketch:

    Good evening. The last scene was interesting from the point of view of a professional logician because it contained a number of logical fallacies; that is, invalid propositional constructions and syllogistic forms, of the type so often committed by my wife.
    ‘All wood burns,’ states Sir Bedevere. ‘Therefore,’ he concludes, ‘all that burns is wood.’ This is, of course, pure bullshit. Universal affirmatives can only be partially converted: all of Alma Cogan is dead, but only some of the class of dead people are Alma Cogan. ‘Oh yes,’ one would think. However, my wife does not understand this necessary limitation of the conversion of a proposition; consequently, she does not understand me, for how can a woman expect to appreciate a professor of logic, if the simplest cloth-eared syllogism causes her to flounder?

    For example, given the premise, ‘all fish live underwater’ and ‘all mackerel are fish’, my wife will conclude, not that ‘all mackerel live underwater’, but that ‘if she buys kippers it will not rain’, or that ‘trout live in trees’, or even that ‘I do not love her any more.’ This she calls ‘using her intuition’. I call it ‘crap’, and it gets me very irritated because it is not logical. ‘There will be no supper tonight,’ she will sometimes cry upon my return home. ‘Why not?’ I will ask. ‘Because I have been screwing the milkman all day,’ she will say, quite oblivious of the howling error she has made. ‘But,’ I will wearily point out, ‘even given that the activities of screwing the milkman and getting supper are mutually exclusive, now that the screwing is over, surely then, supper may now, logically, be got.’ ‘You don’t love me any more,’ she will now often postulate. ‘If you did, you would give me one now and again, so that I would not have to rely on that rancid Pakistani for my orgasms.’ ‘I will give you one after you have got me my supper,’ I now usually scream, ‘but not before’– as you understand, making her bang contingent on the arrival of my supper. ‘God, you turn me on when you’re angry, you ancient brute!’ she now mysteriously deduces, forcing her sweetly throbbing tongue down my throat. ‘Fuck supper!’ I now invariably conclude, throwing logic somewhat joyously to the four winds, and so we thrash about on our milk-stained floor, transported by animal passion, until we sink back, exhausted, onto the cartons of yogurt.

    I’m afraid I seem to have strayed somewhat from my original brief. But in a nutshell: sex is more fun than logic– one cannot prove this, but it ‘is’ in the same sense that Mount Everest ‘is’, or that Alma Cogan ‘isn’t’.

    Goodnight.

  7. 157
    James says:

    Re #143: [The difference in timescales between the exhaustion of fissionable materials on Earth and of the sun is many orders of magnitude, so your comparison is somewhat absurd...]

    We have a civilization that has existed for maybe 10^4 years, facing a problem that might doom it in 10^2 years if it doesn’t do something in the next 10^1 years. On that scale, worrying about the Earth running out of fissionables in 10^5 years, or the sun running out of hydrogen in 10^9 years seems equally absurd.

    [Where did I say I wanted to study the problem for another decade or two?]

    Back in #133: “We need to determine which of them, in what mix, will give the best results, in relation to climate change, and whatever other advantages and drawbacks they have.” That certainly implies a considerable period spent studying the various technologies to determine which is best, doesn’t it? Not to mention the indefinite time needed for some government (or worse, intergovernmental) commission to define “best” for us. And then we can wait for the National Energy Service to get around to installing the selected alternatives for us – after of course setting up a Civil Service exam procedure for prospective installers, hiring several layers of administrators, waiting through the court challenges…

    You can do all this, or you can just start taxing CO2 emission at (per the news this morning) $20 or so per ton, and let people decide how best to deal with the increased cost.

    [We need swift inter-governmental agreements on emissions targets...]

    Yes, and we need cold fusion, anti-gravity, and universal brotherhood. I expect to see at least one of those before any practical agreement of that sort.

  8. 158
    Rod B. says:

    re P. Lewis (148) I agree 100%! I was specifically chiding tamino ’cause he just took his mostly valid point to the ridiculous zealous extreme and said there was “no cooling” specifically between 1940 and 1970.

  9. 159
    Rod B. says:

    re P. Lewis (148) As an aside, with your background in the steelworks of Wales (or other places, e.g. Pittsburg, for others) you’re probably aware that the aerosols responsible for the cooling starting in 1940 were belching out in tons long before… Just a thought.

  10. 160
    Ray Ladbury says:

    Rod B. said, “you’re probably aware that the aerosols responsible for the cooling starting in 1940 were belching out in tons long before… Just a thought.”
    Yes, and it is a reason why England was synomymous with “fog”–which wasn’t fog at all, but smog. And it did have a local effect. There’s a reason why those “dark Satanic mills” were dark. What you seemingly fail to appreciate is that energy consumption, like population tends to rise geometrically, so we were spewing a whole helluva lot more soot into the air in 1940 than in, say, 1910. This trend continued until we actually did something about it–passing clean air legislation, which happened around the same time in the US and Europe. It is not just the presence of particulates, but their amount, and unlike CO2, particulates do not accumulate, since they have a short lifetime.

  11. 161
    Caz says:

    Re: 155

    One last note: the latest corrections to the RSS and UAH satellite temperature data bring them into agreement with the surface temperature record and the computer model results for the lower troposphere. So, you’re wrong on all counts

    Which surface temperature record are you talking about. GISS? HadCrut?
    The surface temp records have been diverging over the past decade so much so that there has been a study to try and identify the reasons.

    Even after corrections, the 30 year trends for RSS and UAH differ so I’m not sure how they both agree with the surface record. It is true, though that over the past decade RSS, UAH and HadCrut have a very similar – more or less flat trend.

    You chose a period between 1940 and 1970 to show a NON-significant trend and hence conclude there was no 30 year cooling. We could just as easily find period of NON-significant warming (or cooling) and hence conclude there is 30 year warming.

    PS if you want an argument about stats – we’ll take it elsewhere e.g. your site.

  12. 162

    Re #155 — Tamino, no one disputes that your statistical analysis is accurate. It’s just that the phrase “global cooling” has been applied to the period from 1940 to 1970 when the slope of the rate of temperature increase changed. You’re probably right that we shouldn’t call it “cooling,” but it is a distinct period on the graph and we need to call it something.

  13. 163
    FurryCatHerder says:

    Gavin,

    I read the planetary energy imbalance thread you referred me to in #150. It also didn’t answer my question (it wasn’t even in the right neighborhood).

    To make the question clearer, has anyone ever assumed average emissions of all sorts, average solar output, average everything, for the various periods between 1900 and some recent date, and used those values to “predict” the climate in 2000 the same way the IPCC has used average values to predict climate change between the current date and 2100 using the same models?

    (And so you know where I stand, I concede that if we can find, and can afford to burn, the fossil fuels to produce the CO2 levels in the IPCC report, we’re in big trouble, but I don’t believe that is economically feasible. I think we’ll wind up in a fairly nasty economic mess long before the climate gets completely trashed. Rising demand and declining reserves don’t bode well for anyone — climatologists included — who assume oil will continue to be plentiful and cheap.)

    [Response: I don't follow you. The simulations in the post I pointed you to were exactly what you describe - you start in the 19th century and with the observed changes in forcings of CO2, CH4, solar, volcanoes etc. you run forward until 2000 and you get the current temperature anomaly. The hindcasts have been done with all the models as part of the IPCC AR4 process. If this isn't what you mean, let me know. -gavin]

  14. 164
    FurryCatHerder says:

    Gavin,

    The things I’ve seen in the various reports and papers I’ve read over the years, particularly the graphs (as I recall — I’m walking out the door at the moment, so I can’t go back and check) that were included in the thread you referenced, show the actual consumptions, events (volcanic erruptions, etc.) and so forth.

    The models included in the IPCC report are all, obviously, predictions based on assumed amounts of consumption, etc. What I’m looking for is a paper which describes how the models behave if the events of the 20th century were “predicted” based on average consumptions, emissions, volcanic events, solar output, etc.

    In other words, if the average activity is fed into those models as averages, rather than as actual data, how well do the models hold up? If instead of an actual Mount Pinatubo there is an “averaged out” mount Pinatubo (et cetera), do the models over predict or under predict climate change? If instead of actual fossil fuel use, with all the ups and downs of wars and depressions, there is an averaged out fossil fuel use, do the models over predict or under predict climate change?

    [Response: Ahh... That's a little clearer. First off, people only do 20th Century simulations in order to match observations, and so everyone uses the actual forcings, not forcings that would have been estimated in 1900 if anyone had thought to do that. Therefore I don't think that exactly that you want exists. However, the closest to what you want is probably the early Hansen simulations (published in 1989) and which contained estimates for the forcings into the future and ended up with temperature changes that were pretty close to what happened. They even used a hypothesised volcano in 1995. -gavin]

  15. 165
    tamino says:

    Re: #161 (Caz)

    It is true, though that over the past decade RSS, UAH and HadCrut have a very similar – more or less flat trend.

    If we analyze GISS data using linear regression, we get the following temperature change rates:

    GISS GLB_TSST:
    From 1995 To 2007 2.2 +/- 1.1
    From 1996 To 2007 2.4 +/- 1.3
    From 1997 To 2007 2.1 +/- 1.5
    From 1998 To 2007 2.1 +/- 1.9
    From 1999 To 2007 3.6 +/- 1.7
    From 2000 To 2007 3.1 +/- 2.1

    Every one of those time intervals gives a statistically significant rate of increase. If we do the same using HADCRUT3, we get:

    HADCRUT3:
    From 1995 To 2007 1.9 +/- 1.5
    From 1996 To 2007 2.0 +/- 1.8
    From 1997 To 2007 0.9 +/- 1.7
    From 1998 To 2007 0.7 +/- 1.9
    From 1999 To 2007 2.3 +/- 1.5
    From 2000 To 2007 2.0 +/- 1.8

    Only the time frames 1997-2007 and 1998-2007 fail to give a significant response to linear regression. But the time frame 1999-2007 (and 2000-2007) does give a significant result. That’s a clue: there is indeed a trend in the last decade, but it’s not linear. If we do higher-order polynomial regressions, or Fourier fits, we do get statistically significant response for the time frame 1997-2007 (as well as 1998-2007). So there is most definitely a trend there, even in HadCRU data; your “more or less flat” claim doesn’t hold water.

    The main reason for the difference in GISS and HadCRU results is that the HadCRU data show a much larger response to the el Nino of 1998. The statistically strongest model for the last decade is: big rise due to el Nino, big fall due to subsiding of el Nino, warming 1999 to the present.

    When we look at the time frame 1940 to 1970 (HadCRU or GISS), again there’s no statistically significant response to linear regression. But again, applying higher-order polynomial regression or Fourier fitting does give a statistically significant response. That’s why I don’t claim there’s no trend from 1940 to 1970; I’ve pointed out all along that there was a notable cooling from about 1944 to about 1951. But I do state that the trend is not linear, and it’s certainly not correct to characterize that time period as “three decades of cooling.”

    PS if you want an argument about stats – we’ll take it elsewhere e.g. your site.

    I’m not the least bit interested in arguing stats with you, here or anywhere else. Not only have we beaten the horse thoroughly dead, you seem to want to beat its ghost as well. I’m done.

  16. 166
    ray ladbury says:

    Re 162. Words are important when you get to politics. To call the ’40-’70 period global cooling is inaccurate and it makes it sound as if global warming is a new thing that came on the scene in 1975 and hence less certain.
    The medical procedure known as “IDX” or intact dilation and extraction was dead as soon as abortion opponents stuck the name “partial birth abortion”–a medically meaningless description.
    We need to be aware of our lexicon. Global warming sounds like a good idea to folks north of the Mason-Dixon Line from December to March. And Global cooling makes it sound as if scientists can’t make up their mind. I would recommend sticking to the more accurate “climate change” and perhaps calling the ’40-’70 period a “hiatus” in the overall warming trend due to aerosol pollution.

  17. 167
    Steve Bloom says:

    Re #161/165: Caz, you picked a fight over stats with someone who is rather more qualified at time series analysis than any of the “objectivists” over at ClimateAudit, and look what happened.

    As Gavin has pointed out here in the past, the argument that there has been no little or no warming over the last ten years depends on disingenuously starting an analysis at a record year and stopping before the next one. (This transparent disingenuousness is why Tamino is uninterested in arguing with you further, BTW.) We have yet to hit an unambiguous new reord year post-1998, but if one looks back over the record of the last thirty years or so it’s possible to identify several multi-year periods of “cooling” in between new record years. As the warming proceeds unevenly, that will always be true. Of course, when we do hit that next clearly warmer year (and this year is a possibility), I’m sure the “auditors” will come up with some other lame argument.

  18. 168
    Blair Dowden says:

    I am going to jump into this “global cooling” issue. I want nothing to do with cherry picked data showing a cooling since 1999 or whatever. But I do not think the 1940-1970 cooling should be dismissed as random fluctuations. Globally the cooling was small, but the further north you go the more significant it gets. For example, see figure 2.6 of the Arctic Climate Impact Assessment where the trend is clear and greater than one degree C. Looking at figure 1a of this Johannssen et. al. paper we see both the early 20th century warming and subsequent cooling was regional, centered on the Arctic, rather than truly global. They argue that the warming/cooling was caused by “natural variability of the climate system”, but argue the more recent warming has a much more global distribution and must be primarily anthropogenic.

    I am not at all supporting a global warming is natural argument, just pointing out that significant events should not be dismissed as random.

  19. 169
    Pat says:

    Re 136:

    I would assume that solar irradiance is in terms of the W/m2 on a plane normal to the rays of the sun. In contrast, the average change in insolation at the top of the atmosphere is the change in solar irradiance divided by 4 (Because a sphere’s surface has 4 times the area as it’s cross section). Then, you have to muliply by (1-albedo)=~ 0.7 to get the solar radiative forcing, the change in absorbed solar radiation. So solar radiative forcing of climate on Earth will typically be around 0.175 times the change in solar irradiance.

  20. 170

    “I am not at all supporting a global warming is natural argument, just pointing out that significant events should not be dismissed as random.”

    Yes, some random tornadoes came by today, it must be a trend.

    You don’t have to apologize, Blair, your FUD is clear.

  21. 171
    L.R. says:

    Re # 126, 134, 146; It seems to be highly reasonable to make clear time period distinctions within the cooling phase from 1940 to about the 1970s. But the cooling period started very precisely in winter 1939/40, particularly in Northern Europe which experienced suddenly the coldest winter for 110 years, although the late 1930s had been the warmest years for presumably 200 years, and the autumns the warmest for almost 500 years. Material to this question can be found on the reference link Re #2 above, or on http://www.1ocean-1climate.com which displays an interesting front page story.

  22. 172
    Blair Dowden says:

    Re #170: Thomas, do you actually read beyond the first sentence? I explained that the apparent 1940-1970 cooling was really a recovery from the earlier warming, which was a regional event. This takes nothing away from the fact the recent warming is anthropogenic. Reality is complex and sometimes uncertain. The fear and doubt are in your own mind.

    Maybe L.R. in #171 should re-read what I said, and check my references. He will find a real explanation for the apparent cooling, far different than the rubbish he referenced.

  23. 173
    Ray Ladbury says:

    Blair, You are talking about an event on a large but still local scale–not a global scale. No one is arguing that the period from 1940-1975 was not in some way anomalous. There is even a fair agreement that part of it was caused by aerosols, and part by ocean currents (in the North). The important points, however are:
    1)The cooling trend was not global.
    2)To say that some years saw cooling in the period from 1940-1975 is a very different thing than saying 1940-1975 was a period of cooling.
    3)The term “global cooling” is inaccurate and is used with relish by denialists.
    No one is saying that cooling did not occur during the period–from 1940-1950–and then a flat trend from about 1950-1975. Moreover, the amount of cooling seen depends on the dataset–quite unlike the warming we are seeing now. That right there tells you that what you were seeing was not global.

  24. 174
    Nick Gotts says:

    Re #157 “Back in #133: “We need to determine which of them, in what mix, will give the best results, in relation to climate change, and whatever other advantages and drawbacks they have.” That certainly implies a considerable period spent studying the various technologies to determine which is best, doesn’t it?”

    No, it doesn’t, if you mean 20 years plus, as you said previously. In the short term, it’s clear enough how to get started: energy efficiency, demand reduction (mainly in rich countries), plus carbon capture and sequestration from coal-fired power stations for China and India, where the choice for coal has already been made and would be very hard to reverse. For low C02 producing electricity generation in rich countries, I’d say key decisions at government level could be taken fairy quickly (months to a couple of years) once the commitment to reduce GHG emissions (see below) is made. Different options require different infrastructure and R&D investments, institutional frameworks and political coalitions, which is why a shoulder-shrugging “leave it to the market” is so hopeless: which options win out in “the market” will be determined by decisions on infrastructure and institutions and if no such decisions are made, none of them will develop fast enough.

    “You can do all this, or you can just start taxing CO2 emission at (per the news this morning) $20 or so per ton, and let people decide how best to deal with the increased cost.

    [We need swift inter-governmental agreements on emissions targets...]”

    Without inter-governmental agreement (which doesn’t need to involve more than the G8 + China and India at most, and fewer would almost certainly do), it’s very unlikely serious emissions taxes or rationing will be introduced, because big business won’t stand for being disadvantaged relative to foreign competitors.

  25. 175
    Hank Roberts says:

    “L.R.” and earlier “arnd” — we keep seeing people pop in and drop links to one or more of these enthusiast’s pages (Naval War thesis; warchangesclimate.com; bernaerts-sealaw.com; 1ocean-1system.de; oceanclimate.de; seaclimate.com; and now 1ocean-1climate.com). I may have missed a few pages or userids; often the userids are also links to the same websites. It may be boosting Google pagerank by having links from RC to there.

    Asserting “global cooling from naval war” in the absence of science, math, and temperature data isn’t convincing; the approaches here at RC make sense because they do more than assert their ideas.

  26. 176
    James says:

    Re #174: There certainly seem to be some gaps in that. For instance, you’d have “…carbon capture and sequestration from coal-fired power stations for China and India…” when no one knows whether this technology will actually work, let alone how to do it economically. Suppose it turns out not to be viable? Then you’ve committed public money, rather than the fortunes of greedy capitalists, to building these coal plants.

    Similarly with energy efficiency & demand reduction: how do you do that effectively without some market incentive? Send squads of eco-cops around to change out everyone’s incandescent light bulbs?

    [...it's very unlikely serious emissions taxes or rationing will be introduced, because big business won't stand for being disadvantaged relative to
    foreign competitors.]

    Why should it disadvantage “big business”, particularly? Understand that I’m not suggesting tax increases, but tax shifting. Instead of collecting X dollars in sales tax or VAT, it would collect the same amount from a CO2 tax. (Which could be applied to imports as well.) Neither business not the consumer would be at any particular overall disadvantage, and they’d have the opportunity to gain advantage by reducing energy use. Of course in the long run the least efficient would be at a disadvantage, but this is always the case. Instead of denying the market, you target it to produce the results you want.

  27. 177
    Blair Dowden says:

    Re #173: Ray, we are arguing over semantics here. First, I think the significant event in question is the warming in the early 20th century. Although the warming was felt globally, it was concentrated in the Arctic, far more than the with global warming that is occurring today. So there was a regional warming, with “natural” (ie. we don’t know what) causes, and possibly a separately caused (solar?) global warming as well.

    When the regional event stopped, the consequence was regional cooling, but enough of it that it was felt globally. So is it correct to say there was 30 years of global cooling? It depends on what kind of averaging is used. You can get 30 years of gradual cooling, or shorter periods of more rapid cooling. I realize that out of the context I just described talking about global cooling is misleading, and yes, useful for denialists.

    The main point I want to get across is there was no real cooling “event”, but rather the cessation of a prior warming event. But the global cooling did occur.

  28. 178
    Ray Ladbury says:

    Blair, the reason I am arguing semantics is because our opponents sieze on semantics any chance they get. Thus, while there was cooling in this period, it wasn’t globing, it wasn’t sustained. So why do we persist in handing them an issue that just confuses the public?

  29. 179
    Rod B says:

    re Ray (173): I’ll admit I’m not intimately familiar with all of the data measurements and their processing, but it seems grossly suspicious to say late 1800s to 1940 and 1975 to present were good global measurements, but that 1940-1970 cooling thing — well that was just a regional anamoly. How convenient.

  30. 180
    John Mashey says:

    Re: Rod B (179) 1940-1970: I thought all this as talked about earlier (under dimming, which ha been regional), but NASA GISS has a nice short reference:

    http://www.giss.nasa.gov/meetings/pollution2002/d2_baltensperger.html

    They see a big spike in sulfates in Alpine ice cores, going back down around 1975-1980, a similar pronounced spike in Arctic (Greenland), and nothing in Antarctica. It is quite plausible that this is related to the rapid, dirty industrialization that started ~ WW II, of which the most concentrated effects were in parts of N. America and Europe, and which certainly continued, and which certainly had visible local effects [I grew up near Pittsburgh, PA ... and they were certainly visible, as long as there was a steel business there.]

    Another paper analyzes Himalayan ice-core records:
    www-bprc.mps.ohio-state.edu/Icecore/Abstracts/Duan%20et%20al%20GRL%202007.pdf
    This shows South Asian sulfates rising, at same time as N. American/European ones have been dropping (Clean Air Acts).

    I’ve lost track of the reference, but I did see a modeling study that showed that by accepting really awful acid rain, one could locally hold back warming for a decade or two in several regional areas… China may be trying…

  31. 181
    Blair Dowden says:

    Re #178: Ray, now we have a difference in philosophy. I want to understand every aspect of climate, and do not want to be restricted because it might be misused to “fool the public”. Denialists will find a way to fool the public anyway. Some of the sources of climate change are non-anthropogenic, such as a good part of the early 20th century warming. As greenhouse gas levels rise, non-anthropogenic forcings become less significant.

    Re #180: John, I do not think that aerosols had much to do with the 1940-1970 cooling (that word again) because there is no need for a negative forcing to explain what happened after the end of the prior warming event. Aerosols did not positively contribute to the early 20th century northern hemisphere warming, and greenhouse gas levels were insufficient at the time. We can detect a rise in aerosols, but have little idea of the magnitude. Even today, the current estimate on direct aerosol forcing (from IPCC 2007) is 0.1 to 0.9 watts per square meter. I don’t know what they use for an aerosol forcing in 20th century climate models, but I suspect it is largely guesswork.

  32. 182
    Nick Gotts says:

    Re #176 “There certainly seem to be some gaps in that. For instance, you’d have “…carbon capture and sequestration from coal-fired power stations for China and India…” when no one knows whether this technology will actually work, let alone how to do it economically.”

    Well, CO2 capture from power station exhaust gases has been done for over 60 years by amine scrubbing (in cases where the gas is wanted). Sequestration of CO2 from natural gas fields is already being done in the North Sea and Algeria. The IPCC says it will work in the sense that little of the gas will escape within 1000 years (I’m relying here on referenced information in George Monbiot’s “Heat”). It had better work (and be retro-fittable, which is tougher), given that China is building one new coal-fired power station a week and isn’t about to stop. This is one place where international agreement is clearly needed, and technical research is also needed urgently, whether “the market” says so or not.

    “Similarly with energy efficiency & demand reduction: how do you do that effectively without some market incentive? Send squads of eco-cops around to change out everyone’s incandescent light bulbs?”
    Banning the sale (not use) of incandescent bulbs, and other energy-inefficient technologies, is worth considering – in the case of bulbs, it is already done in Australia. But I’m not arguing against the use of market incentives for energy users, which I favour; I’m arguing against leaving major R&D and production decisions in the energy sector to market forces, which is what you are proposing.

    “Why should it [CO2 tax] disadvantage “big business”, particularly?”
    The point is not that it would disadvantage big business particularly, but that it’s big business that has the influence to stop it.

    “Understand that I’m not suggesting tax increases, but tax shifting. Instead of collecting X dollars in sales tax or VAT, it would collect the same amount from a CO2 tax. (Which could be applied to imports as well.)”
    The basic idea of tax shifting is fine, and in principle applying the CO2 tax to imports should avoid home corporations’ objections, but unless foreign governments have at least agreed to support the measure, how is the home government going to know how much CO2 was generated in the manufacture of imports?

  33. 183
    Ray Ladbury says:

    Blair, I am not arguing against understanding the period between 1940-75. I’m saying that we need to be careful and accurate in describing it. It was not 3 decades of cooling. It was a few years of cooling after a warming event, followed by 2 decades of relatively stable temperatures. Under that description, it is no less interesting to understand, and it doesn’t give the impression to people (nor the opportunity to denialists) that climate is cyclic–which it is not. Scientists need to be as careful with their language as they are with their math.

  34. 184
    Ray Ladbury says:

    Rod B. No. Not convenient. Accurate. If you are looking at a truly global change, then the trend should be robust across data sets and across analysis techniques. The warming trend is, while the cooling trend is not. No one is questioning whether the trend from about 1944-1950 showed cooling in the Northern Hemisphere, nor that the subsequent 20-25 years showed flat trending. That is interesting and is and should be studied. But the cooling was not global, though the flat trend was (and hence is more interesting). Stop looking for conspiracies where there are none.

  35. 185
    Burt V. says:

    The verious contributions about global cooling ca. 1940-1970 and reference gave me a lot information, particulary concering the arctic winters in Northern Europe starting with winter 1939/40, with subsequent cooling in a wider region, which seems to be still unexplained. At least no one touched the question, or only indirectly e.g. #172, #175. It was not CO2, and presumably it did not came out of the blue. Or?

  36. 186
    Hank Roberts says:

    Burt, the “naval war causes cooling” people regularly drop links in many climate forums. They say oil spills coincided with warming during the world wars, and infer causation, but I looked for quantities and found that, back in those decades, natural seepage of petroleum far outweighed the tonnage of shipping sunk.

    Even today natural seepage is perhaps half the oil spilled, the rest being from shipping. So yes, petroleum spilled in the water has perhaps doubled from the natural baseline seepage. Nobody that I know of has a theory for why that would change the planet’s radiative balance. If it calms the waves and makes them better mirrors it ought to increase reflection. If it’s a source for CO2 by the petroleum breaking down, it’s still a small one compared to the burning of the fossil fuel that survives transportation.

    Papers modeling climate retrospectively show ocean currents and other known changes sufficient to explain that. Read the science suggested above, it will get you started. You won’t find the alternative explanations on the pages run by the enthusiasts for a single cause for everything.

    Do some searches, you’ll find the information.

  37. 187
    Rod B says:

    Ray, not conspiracies, but it sure looks deliberately obtuse. All those late 1800s to 2000+ temp vs. CO2 graphs simply trumpet “global”. Now you might be right about the roughly 1940-1970 “cooling” period being exclusively something less than global (though, why, is perplexing….) but it sure makes for a hard-to-explain ugly baby. Within scientific circles I see no need or benefit to be so devious (though ironically I can understand it in non-scientific discourse.)

  38. 188

    If anybody is interested, I have proposed the term ‘Neocene’ for the new geological era that is presently (and demonstrably I might add) upon us.

    I did enough research that I am confident it will stick :

    http://cosmic.lifeform.org/?p=292

  39. 189

    Re #188 I think you are a bit late with that suggestion for the geological era that started very recently. Nobel Prize winner Paul Crutzen has already suggested ‘Anthropocene’ which has been widely accepted. There is even an ‘Early Anthropocene’ period. See http://geology.about.com/od/geotime_dating/a/anthropocene.htm for a link to Paul’s proposal published in Nature, and Wikipedia for details of the Early Anthropocene http://en.wikipedia.org/wiki/Early_anthropocene

  40. 190
    Blair Dowden says:

    Re #188: The term “Anthropocene” has already been suggested to follow the Holocene.

  41. 191
    Hank Roberts says:

    I think it’s a bit confusing there; you have an image copy:

    http://www.lifeform.org/files/Neocene_New_Geological_Era.png

    That’s a clickable link to the home page for globalwarmingart.com.

    Below that you have:

    Welcome to the Neocene – A New Geological Era
    http://www.globalwarmingart.com

    People may mistakenly think you got the text with the image at globalwarmingart.com; it might be clearer to just link to his image and separate your text (else the text and the filename are confusing about attribution).

    But I suspect the next era may be named by some AI, perhaps as the “post-Anthropocene” if we don’t get smarter about this stuff.

  42. 192

    Anthropocene? Not a chance. Things are now beyond our control.

    If we do manage to get things under control, then that term might be appropriate, but barring some sort of crash international space program, the chances of that happening now are slim to none. Physics doesn’t lie, it just gets more accurate over time. The result now is crystal clear.

    I’ve passed the testing stage, and have achieved acceptance. I couldn’t care less anymore. Humans no longer deserve this planet. It will shortly be taken away from them. For a little insight into what is to come, I suggest that everyone take a good hard look at Betty Ann Luca’s Pheonix experience.

    When you are living on a spaceship, the very first thing you need to get under control are carbon dioxide and thermal management. It will kill you quicker even than dying of thirst or hunger. We have completely and utterly failed the very first test of intelligence in the universe.

  43. 193

    There is nothing in the name anthropocene which means that man is in control, only that they are the cause, and since new epochs tend to be marked by extinctions, then it implies that man is responsible for the current extinction.

    Of course larger extinctions mark the beginning of new ‘periods’, still larger extinctions herald in ‘eras’, and the largest geological divisions are called ‘eons’. The last two eons were the Proterozoic (early life) and Phanerozoic (visible life). For the next eon beginning now I propose the name Anozoic (No life) or perhaps Necronozoic (dead life.)

  44. 194

    [[Humans no longer deserve this planet. It will shortly be taken away from them. For a little insight into what is to come, I suggest that everyone take a good hard look at Betty Ann Luca's Pheonix experience.]]

    And don’t forget the Urantia Book, Roswell, and Harmonic Convergence.

  45. 195
    Ray Ladbury says:

    Rod B., Look, no one is trying to hide anything about the 1940-1975 period, but the very fact that one can look at the different graphs and they show the effect to greater degrees or lesser and the fact that one can have different interpretations of the graph shows we are not dealing with a robust, global effect. And Tamino is 100% right. Other than the short period from 1944 to 1950, there is no consistent trend, cooling or warming in the data. If you look at the period just prior to 1944, the warming was anomalously high, so it is not surprising that this would be followed by some cooling. If we look closely at what was going on in this period, we might come to an understanding of the oscillation. Actually, I find the period from 1950-1975 even more interesting–precisely because of the relative stasis.
    It is certainly not spin or deviousness to insist on precision, and to say the period from 1944-1975 was one of cooling is imprecise at best and misleading (by some, deliberately so) at worst.

  46. 196

    And don’t forget the Urantia Book, Roswell, and Harmonic Convergence.

    AOL eh? Figures.

    Never met Betty Luca, have you.

    I challenge Mr. Crutzen’s term ‘Anthorpocene’, because that would imply that mankind take complete control of the environment, and return carbon dioxide concentration to ambient levels (say 300 to 320 ppm to ward off any further ice ages), establish a worldwide population commensurate with the carrying capacity of the Earth, and remediate the air, waters and lands of the planet, while preserving abundant wildlife areas, which may or may not happen. The Anthropocene, if it were to occur, would follow the Neocene, since humanity is demonstrably not in control of the Holocene, according to any established control theory. Hence, the Neocene.

    Should the Anthropocene era come to pass, it would reduce the Neocene era, which is demonstrably upon us, to a transient thermal event, an unfortunate but necessary experiment in planetary engineering. At that point one would expect humanity to be a space faring civilization, and then perhaps Ms. Luca may finally get the respect she deserves.

    The Neocene term is the result of research, and not an off the cuff, spur of the moment statement at a conference. The term has demonstrably fallen out of favor as representing the early Pliestocene, and is definitively available. Science is about alternatives, options and challenges. We have indeed also entered the fifth (Pentary) geological era, I might add.

    FWIW, I’ve also somewhat successfully challenged the IAU’s definition of planet. Now that terrestrial planets are in sight, we may soon have many hundreds and thousands of examples available for inspection, and then we may understand more fully the Earth’s place in the hierarchy of extrasolar planets, and the dogma, stigma and indeed hysteria, that surrounds the mere possibility of non-human life in the universe, may eventually fade. Humans may indeed have a place in this universe, but according to the empirical evidence thus far, it is now one of unremarkable and tragic obscurity.

  47. 197
    Ruth Jarman says:

    have you answered pete best’s question #108…couldn’t see it answered anywhere….

  48. 198
    Hank Roberts says:

    Advice to Lord Monckton: buying ads in the WSJ claiming you challenge Mr. Gore to a debate is hubris.
    You don’t have any history of understanding the subject yet. Establish your importance by doing the work.

  49. 199
    Burt V. says:

    # 186; Complete agreement, Hank, whoever says oil spills coincided with warming during the world wars, is certainly wrong. It was unlikely seven decades ago, and is presumably even insignificant today. Until now I have not read all texts of the reference you mentioned, #175, but until now I have not found any text which makes such claim. It seems to me that the “enthusiast” claim something very different, namely the impact of a sudden seawater temperature change on atmospheric air temperature conditions. But I will continue to see whether they indeed link oil spills to cooling (not warming), I will inform you as soon as such claim is indeed made, or can you direct me to the text?

  50. 200
    Hank Roberts says:

    Burt, type “Adrianne” into the search box at top of page, that’ll find you many of the times this stuff was dropped here.
    Or use Google to find strings from this, it’s from one or more of those many web pages tied to his book and idea:

    All that stuff polluted the sea
    and was taken away by the Gulf Current
    or by the Norwegian Current
    up to the North. It was precisely there
    that the “big warming” occurred.

    Everyone’s entitled to their own ideas, but not to insist on attention from other people, nor to insist that scientists recognize them as clever, adopt them, and defend them. The sites are full of ideas. Depth charges used in attacking submarines mixed the layers of the ocean up —-somewhat, locally, briefly. Did that cause the warm water to sink below the cold water and not reappear for thirty years? I doubt it. Compare the energy and mixing there to the amount of mixing that occurs naturally? No numbers, no comparisons.

    I understand you want help understanding Bernaerts’s ideas. I don’t know where you’ll find someone to help you with that. Good luck.


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