This month’s open thread. Try to keep it at least vaguely focused on climate science…!
David B. Benson @229:
Thank you for your reply.
I would still like to determine which of the new IPCC scenarios most closely resembles the EIA’s IEO2011 projection of “1 trillion metric tons of additional cumulative energy-related carbon dioxide emissions between 2009 and 2035″. The new IPCC are named RCPs (Representative Concentration Pathways). Pre-release graphs of them can be viewed HERE. The graph I’m interested is titled “Emissions”, on page 11.
The y-axis of the RCP emissions graph is in Gt of carbon per year. So I divide the EIA’s “1 trillion metric tons of additional … CO2″ by the length of their projection (26 years) and get 38.5 Gt of CO2 per year. Then I divide by 3.67 (the CO2 to C conversion factor) and get 10.5 Gt of carbon per year. But that’s not much help because RCPs show varying emissions over time.
So I try the opposite approach. I make an annotated version of the same RCP emissions graph, and use it to estimate the total additional C added from 2009 to 2035 along the various RCPs. For RCP8.5, it looks pretty close to a linear change: an increase of about 2.25 Gt of C per decade, or 0.225 Gt per year. To compute cumulative emissions given a linear change, I want the sum of an arithmetic progression.
Sn = n / 2 * (a1 + an), where an = a1 + (n – 1) * d.
Here a1 = 0.225, n = 26 years, and d = 0.225, so:
an = 0.225 + (26 – 1) * 0.225 = 5.85
Sn = 26 / 2 * (0.225 + 5.85) = 78.975 Gt C
78.975 * 3.67 = 290 Gt CO2
So if we follow RCP8.5, the IPCC AR5 worst case, we add 290 Gt CO2 from 2009 to 2035, but the US EIA projects adding 1000 Gt for the same period, or 3.4 times as much.
“Well I would say, sir, that there was something dreadfully wrong somewhere.” -Mandrake in Dr. Strangelove
flxible @238 — Thanks.
This is what I get:
Year___ Average ice volume [1000 km^3]
Year___ Average ice volume [1000 km^3]
re my 248, first paragraph – never mind, found it (well, not a map, but good enough).
I’m not following your summation all that well, but on your annotated plot, RCP8.5 has a value of about 11.5 Gt/yr C halfway through your range of interest. Multiplying that by 26 years and your conversion factor gives about 1097 Gt CO2. Seems like you’ve found the track you are interested in.
I think that the reasons why the world will end Tuesday at 4:37PM is spot on topical to this blog, but suggested activities between now and then are not, except in a supporting role. The wiggle room provided by “except” is being further restricted (or eliminated), as everyone knows that an inch = a light year.
One of my less off-topic posts commented on how well the emissions curves proposed by RC as needed to probably keep us at least marginally safe matches the emissions curves for all currently producing fossil fuel sources, thus meaning drilling any more wells would require the closing of the same production quantity of already been drilled wells. Since no existing well will ever be closed before becoming uneconomical to pump, new wells are unwise. That’s probably within the “except” limits, but it led to vast quantities of over-the-top stuff, so just saying no to any and all proposed actions might be the way to go for RC.
One possible solution would be an unmoderated “Solutions” thread (or moderated by non-scientist volunteers). No time spent by the hosts, and folks can interact with their RC friends about that related topic. I see Climate Science as a two step process. First, scientists tell us the shape of the emissions curves which will provide various levels of harm, and then non-scientists decide which curve to follow and how.
Ole Humlum just being his normal self and state that NCDC and GISS no longer can be perceived as trustworthy since he has noticed that at two stations they adjust the temperature in a way that make them fit the “models” better. page 5 in Swedish… http://www.katterno.fi/assets/Publikationer/Katterno.3.2012.SE.pdf
Chris Dudley @253 — Thank you. I’m on it right away.
Chris Dudley @255:
With all due respect I don’t agree. My math shows that for the period 2009 to 2035, RCP 8.5 would entail additional cumulative emissions of approximately 29 Gt of C, or 290 Gt of CO2. This is significantly less than the EIA’s projection of 1,000 Gt of CO2 for the same period. I don’t think it’s correct to simply multiply by 26 as you did. To compute cumulative emissions over a period given a linear change, i.e. a constant yearly increment, it’s necessary to use the sum of an arithmetic progression. My analysis of the chart suggests that 0.225 Gt C @ year is a decent approximation of RCP 8.5′s yearly increment for the time period in question. You can view the arithmetic progression expressed as a table HERE.
“The Chinese are not worried that dealing with global warming will lock them out of economic growth in the 21st century — the Chinese know that dealing with global warming is THE key to economic growth in the 21st century.” SecularAnimist — 6 Oct 2012 @ 3:49 PM
“Here is what Carter predicted at the dedication ceremony: “In the year 2000 this solar water heater behind me, which is being dedicated today, will still be here supplying cheap, efficient energy…. A generation from now, this solar heater can either be a curiosity, a museum piece, an example of a road not taken[almost nailed it] or it can be just a small part of one of the greatest and most exciting adventures ever undertaken by the American people.”
“Huang Ming, chairman of Himin Solar Energy Group Co., the largest manufacturer of such solar hot water heaters in the world, accepted the donation for permanent display there on August 5. After all, companies like his in China now produce some 80 percent of the solar water heaters used in the world today.”
There’s a video of the Carter White House solar panel in Mr Ming’s Solar Science and Technology Museum in China. One reason he has the museum is to inspire his workers – and you can see them laugh at our politician’s stupidity ~45 seconds into the video.
Here’s a simpler illustration of my point. Note the pink right triangle. The hypotenuse follows RCP 8.5, or close enough. We emitted 9 Gt C in 2009, and we’re projected to be emitting 15 Gt C per year by 2035. We want to know the total cumulative emissions, in other words how much additional CO2 we emitted during the period, above and beyond whatever we’d already emitted by 2009. So we want the area under the curve, but the curve is conveniently a line in this case, greatly simplifying the math. All we need is the area of a right triangle, or 1/2 lw.
A = (15 – 9) * 26 / 2 = 78 Gt C, and 78 * 3.67 = 286 Gt CO2
This is 3 Gt less than we got with the previous method (sum of an arithmetic progression), probably due to a fence post error for the final year. Nonetheless, it appears that for the period 2009 to 2035, US EIA’s projected cumulative emissions are approximately 3.5 times greater than RCP 8.5, which is AR5′s worst case. If correct, this conclusion would seem to be newsworthy no?
The comment about a Chinese dedication to solar power and leadership is bogus. 99% of China’s solar power production (half the world’s total) is exported. Dumping investigations are ongoing in both the European Union and the USA. The bleeding edge is Europe (Germany is the big dawg), the USA and Japan tie for second, and the China is 4th. Sell the sob about the lack of leadership someplace else – everyone went back to oil because the price dropped through the floor around 1990.
#260–It’s rather remarkable how often it has been claimed now that all Western economies are irrelevant because China is going to cook our climatic goose no matter what we do. (You’d think that that idea would act to encourage those making this argument to demand that we negotiate an agreement with China, but that’s not generally the case…well, it’s usually a concern troll’s argument, I suppose.)
But there is another side to the Chinese energy policy in particular–the side that has seen them become world leaders in green tech exports in just a few short years, and has had them adding renewables faster than they can integrate them into the grid. Seems strange from the perspective of that ‘other side’ to assume that the US will always somehow still lead in green tech, without any American vision or effort whatever. In fact, the US doesn’t now–not in dollar terms anyway. And how long can US green tech innovation be sustained in this political environment?
During the Obama administration, US wind capacity has doubled, solar has increased by a factor of 6, the relevant loan guarantee program has a current default rate of 2.6%–and the public square thinks it was a $90 billion boondoggle with “half the companies out of business.”
Thank you Gavin for your reply to my comment #239 and to other commenters who also followed up.
I certainly did not intend any disrespect to the hosts. I am profoundly grateful for the challenging scientific work that Gavin and the other hosts have done and continue to do, as well as for the work that goes into maintaining this site — not only their substantive articles but their thoughtful (and tolerant) moderation of an open forum for often unruly discussion.
As I wrote above, it is precisely that scientific work that informs and energizes the urgent desire for solutions that appears again and again in the more-or-less off-topic posts here — and that also inspires in some cases a retreat into despair, as the news from the front lines of climate science continues to rapidly worsen.
I shall endeavor to keep my advocacy for solutions — and commentaries on the obstacles to their implementation — for more appropriate venues, and will continue to value this site for the context and insight into climate science that it excellently provides.
As of now, here by the High Arctic Barrow Strait (74 degrees North), It was -5 for more than week and there hasn’t been any grey ice until temperatures reached -11.5 C, the grey ice was minuscule as the -11 C lasted a few hours and it warmed to -6 C afterwards.
Here is my question to Gavin like Sea ice modellers; Given that Cecilia Bitz 2007 projection was uncannily right, (by the way congrats to Cecilia and colleagues)
with sea ice morphology nearly identical to September 2012 at Minima. Could the temporal projection mistake of 30 years be explained by sea ice models creating more extent or volume since they perhaps erroneously start creating sea ice when surface air temperatures reach -2 C instead of -11 C?
Having a look at the models SURFACE temperatures as well as SST’s as they create ice would help answer this question.
I think perhaps you don’t understand the units on the chart. These are annual emissions, not cumulative emissions. If they were cumulative, they would not fall off.
“….and then non-scientists decide which curve to follow and how.”
Dismal scientists might be offended by that characterization….
Chris Dudley @259: I understand that the units are annual emissions. I’m using the annual emission figures (which in RCP8.5 are increasing almost linearly with time) to compute the cumulative emissions for a specific period, because that’s the format of EIA’s projection: “1 trillion metric tons of additional cumulative energy-related carbon dioxide emissions between 2009 and 2035″. Cumulative emissions are the area under the curve, or the hypotenuse in this serendipitously easy case.
While we’re at it, here’s another annotated chart which uses a similar approximation to show how long it would take RCP 8.5 to reach cumulative emissions of 1,000 Gt of CO2. The fit isn’t quite as good in this case, but it’s good enough to illustrate my point: RCP 8.5 would reach cumulative emissions of 1,000 Gt CO2 in 2053, 18 years later than EIA’s projection.
Inserting myself into the discussion mostly from Chris Korda (143, 227, 251, 259), with occasional responses by Chris Dudley (255, 266):
To Chris Korda:
Let’s go back to the pre-release IPCC RCP graphs you mentioned in #251. You clearly noted that the y-axis is in GtC, not GtCO₂.
Looking at the chart I pick off approximately “9″ for 2009 and “15″ for 2035. Now, we cannot check the figure for 2035 by looking at history, but we can pick off the 2009 figure from the following:
CDIAC: world 1751 to 2009 carbon emissions table
There, you will find the figure 8738 (millions of metric tons) for the year 2009. This is pretty close to what my eye picked off from the pre-release chart you talked about.
Just as a note, CDIAC keeps destroying old records from their site, so while you can find the above link and the following one:
CDIAC: world 1751 to 2008 carbon emissions table
You can no longer find this one:
CDIAC: world 1751 to 2006 carbon emissions table
But I happen to have the numbers for 2005 from all three. In 2006, they said 2005 was 7971; in 2008, they say it was 8086; in 2009, they say it was 8106. You can see they are rising a little as they adjust the figures for reasons I can’t pretend to understand or know about. So “9″ seems like a good figure for 2009, to me. You will just have to accept (or check for yourself) my estimate of “15″ for 2035 for purposes here.
The rate of change does indeed appear close enough to linear for that period, so estimating a slope is useful. I calculate ⁽¹⁵⁻⁹⁾⁄₍₂₀₃₅₋₂₀₀₉₎=⁶⁄₂₆ ≈ 0.23. This is close to your own estimates. So far, we are on common ground I think.
The area under the curve is the total in GtC. You don’t need to use sums of discrete values (which approximate close enough, but really it is better to just use calculus.) The equation is just V₀⋅t + (k⁄2)⋅t², where V₀=9 GtC/yr, k=0.23 GtC/yr², and t=26 years. I get about 312 GtC, plugging in the numbers. Multiply this by 3.667 to get GtCO₂ and I get about 1143 GtCO₂. This appears to me to comport with the “IEO2011 Reference case projects about 1 trillion metric tons of additional cumulative energy-related carbon dioxide emissions between 2009 and 2035″ that you cited in #143, which clearly states CO₂ in the sentence. So I think there isn’t a big disconnect here. It’s not good news. But the numbers align. (The thing that drew me immediately to wonder was your own computed factor of disparity, which was 3.4 — close enough to 3.667 that I spent a moment longer thinking about it.)
I don’t like the fact that the pre-release paper about ICPP RCPs happens to show RCP8.5 as the worst case emission scenario in that chart and that this scenario also happens to be the apparent reality in the International Energy Outlook from 2011. If the IPCC RCPs don’t include anything worse and if we are, in reality, on track for this worst case, then the other RCPs are wishful proposals more than anything else. That’s very bad. But that seems to be reality, too. I think I will use RCP8.5 as the ONLY scenario I use for thinking purposes until AFTER I see serious political action AND YEARS AFTER I see significant implementation already taking place. Until then, RCP8.5 is reality.
I see it now. You are integrating the triangle, the area above 9 Gt C/yr. I am integrating the area under the curve, down to zero. I think you are perhaps interpreting “additional emissions” or some such phrasing as an increase over 2009 annual emissions. I think additional emissions means more emissions as opposed to no emissions in this case. A more formal integration of the area under the curve can be found in #269 that is in fairly close agreement with my by-eye estimate.
“Four-fifths of the total energy-related CO2 emissions permitted to 2035 in the 450 [ppm CO2] Scenario are already locked-in by existing capital stock, including power stations, buildings and factories. Without further action by 2017, the energy-related infrastructure then in place would generate all the CO2 emissions allowed in the 450 Scenario up to 2035. Delaying action is a false economy: for every $1 of investment in cleaner technology that is avoided in the power sector before 2020, an additional $4.30 would need to be spent after 2020 to compensate for the increased emissions.”
2011 IEA World Energy Outlook
The IEA 450 Senario is to meet the 2 degrees C global warming limit.
Chris (255, 266, 270), Jon (269): Thank you for your comments, I understand my mistake now. As you say I wasn’t taking the “area under the curve” all the way down to zero. In my triangular area illustration, if I add the area of the triangle (78 Gt C) to the rectangular area beneath it (9 * 26 = 234 Gt C), I get 312 Gt C, the same result Jon gives in #269. I retract my statement about there being a discrepancy, and apologize for wasting time with this stupid math error.
We’re getting a bit of China bashing going on here. I’ve pointed out that the climate science indicates that blame for the dessicating assault on US soil that we have experienced must be laid at China’s feet and a (not very large) tariff should be imposed to exact reparations for damages. It is a threshold thing and it might just as well have been us or India who deserved the blame had the threshold come earlier or later.
But we have a long and useful reparations history with China. The Boxer Indemnity was used to build Tsinghua University. Under the unequal treaties, we also made the opium trade illegal to help with China’s addiction problem. If the tariff I’m suggesting helps to get some thinking going about fossil fuel addiction, then it may be useful in that manner as well and not just in making our farmers whole.
China deserves very close attention and carefully calibrated diplomatic handling. Bashing is not called for.
If anyone is still interested in the Younger Dryas – Anders Carlson and Peter Clark have posted a pdf copy of their latest review article on his UW Madison Geosciences page. I’m sure you can find it on your own.
It is both comprehensive and state of the art. There remain some unanswered questions in the Thunder Bay and Lake Nipigon area though. If anyone wants to discuss it, I would be happy to respond to any and all ideas on this, but I’m tending to the belief that the impact proxies, if they are genuine, are sourced from the Gulf of St. Lawrence area and not Nipigon as I have proposed.
Kevin McKinney wrote: “During the Obama administration, US wind capacity has doubled, solar has increased by a factor of 6, the relevant loan guarantee program has a current default rate of 2.6%–and the public square thinks it was a $90 billion boondoggle with ‘half the companies out of business’.”
Well, here I am going off-topic again in exactly the way I said I wouldn’t … but there is no mystery as to why “the public square” thinks that: for exactly the same reason that “the public square” thinks there is serious scientific debate about whether global warming is even happening.
It’s because there is a massive propaganda campaign to discredit, disparage, denigrate, undermine and destroy the wind and solar energy industries, which is every bit as vicious as the similar campaign against climate science, and funded by the same entities.
The “half the companies out of business” bit is, in fact, a direct quote from Mitt Romney in last week’s TV debate:
“And these [clean energy] businesses, many of them have gone out of business, I think about half of them, of the ones have been invested in, have gone out of business.”
“And these [clean energy] businesses, many of them have gone out of business, I think about half of them, of the ones have been invested in, have gone out of business.”
There was no rebuttal from either the moderator or from President Obama.
The New York Times mustered the courage to call this blatant lie “an exaggeration”.
#262–There’s a kernel of truth to the contention that China has not deployed anything like the amounts of solar exported–though do we demand this in other export categories, or of other countries?–but Chinese wind power has grown tremendously. Moreover, see this update on Chinese solar:
Perhaps I should have added to my previous comment that US solar capacity right now is in the ballpark of 5.7 GW, and German capacity is about 7.5 GW. So the Chinese plan, if realized, would see US deployment exceeded and German deployment approached by the end of this year.
We’ll see if that happens–though deployment of wind in China and solar in India have both gone faster than expected in the past, so it might well come to pass. Either way, I don’t think that the plan merits a sneer toward “Chinese commitment to renewables.”
German solar produced 22 GW of actual output back in May:
So, Germany can still sneer at the Chinese plan if they like.
Captcha says: “Rejoissez”–really!
> I’ve pointed out
But attribution requires more than this.
You’re attempting to assert politics based on your opinion, claiming “science” — without citation, without awareness of natural variation, and in a forum that hopes for more than handwaving.
or if you prefer pictures
“… Years as dry as 1936 or 1939 during the Dust Bowl drought frequently occurred year after year, and often with no break, (e.g. between 1140 and 1165) during medieval times….”
Lay that at the feet of King Arthur and demand reparations.
uh, oh, I’m getting snarky. Time I took a break from this.
Hard to know how the amount of carbon being released by erosion and warming of permafrost to the atmosphere factors in, except to note that estimates seem to be being upwardly revised: http://environmentalresearchweb.org/cws/article/news/51081
Revise upward estimates of released carbon from Arctic and Siberian permafrost: http://environmentalresearchweb.org/cws/article/news/51081
Re 273 – at the risk of more OT (but this will be my only comment here about it): the solution you propose is fine; the reasoning is not – China’s emissions are on top of our’s and others’ and China itself is not free of global warming’s reach.
Jim Larsen suggests the most elegant of solutions* – a global emissions tax. I like that. I have at various places discussed various things to put in place absent such policy attempting to accomplish something similar in a quasi-fair way, for example here: http://scienceblogs.com/stoat/2012/06/25/carbon-tax-watch/ ,
(a little background on my reasoning/opinions/speculations, though it’s probably not necessary:
http://www.realclimate.org/index.php/archives/2011/05/nobel-laureates-speak-out-2/comment-page-1/#comment-207237 )(not to imply my ideas are all that original (although I’ve never heard anyone else discuss the backtax idea so much, but I easily could have missed it).
A tariff would give us the ability to tax domestically without shifting production overseas; effects on (relatively green) exports may be similiarly ameliorated. A ‘polluter pays’ tax (the costs of which should, via normal market mechanisms, tend to be distributed among the benificiaries of the polluting activity, including internationally, other things being equal) doesn’t just provide revenue to deal with damages (or avoid them) but also produces a price signal which reshapes behaviors (once decided, even before going into effect) in suppliers, consumers, and investors – the supply and demand curves shift making alternatives more abundant, etc.
*- not to suggest that this solution will do it all, but it makes the other things easier to do/more likely to be done.
It should be obvious, but to be clear, I meant in the comments @ http://scienceblogs.com/stoat/2012/06/25/carbon-tax-watch/ ; I am obviously not the blogger. (You can’t link to individual comments over there, that’s why I just gave the link to the blog post.)
We already covered part of the $90 billion spending earlier, and yes Romney was way off on his statement about half the companies. Apart from that, I think your statement is way off. Romeny’s statement was an attempt to paint Obama as a big spender of pie-in-the-sky projects. It is not part of some massive propaganda campaign (although you could say that any presidential campaign is largely propaganda). This is completely seperate from the scientific debate, wheth or not you admit it occurrance.
Perhaps you’d like to read this link:
“The deadly European heat wave of 2003, the fiery Russian heat wave of 2010 and catastrophic droughts in Texas and Oklahoma last year can each be attributed to climate change. And once the data are gathered in a few weeks’ time, it’s likely that the same will be true for the extremely hot summer the United States is suffering through right now.”
From Rep. Broun’s recent remarks , it is clear that under no circumstances shouldclimate scientists wear antler hats to Georgia Tech Christmas parties.
[Moderators: You may have already seen an early version of this post, but hopefully not; I posted an earlier version yesterday and waited more than 12 hours before giving up and assuming browser/captcha issues.]
Chris Dudley, Jon Kirwan: Thank you very much for your helpful corrections. I see my mistake now: as you say, I wasn’t taking the area under the curve all the way down to zero. If I add the area of my triangle (6 * 26 / 2 = 78) to area of the rectangle beneath it (9 * 26 = 234) I get 312 Gt C, the same figure Chris gives. I retract my statement about there being a discrepancy, and apologize for wasting time with stupid math errors.
FWIW here’s a corrected version of my annotated AR5 emissions chart. It’s still potentially useful, because it vividly demonstrates the concordance between RCP8.5 and IEO2011 without resorting to math any harder than geometry. That’s good for people who are weak on calculus, like me.
Now that we’ve established that RCP8.5 fits IEO2011, we should be able to answer the two questions I posed back at #227.
1) What will the impact (of the additional 1,000 Gt CO2) be on total global cumulative CO2 emissions? Specifically anthropogenic emissions, since the industrial revolution. In other words, assuming RCP8.5, what will total industrial/fossil-fuel CO2 emissions have reached by 2035? In order to answer this, I need an estimate of cumulative anthropogenic CO2 emissions from 1750 to 2009 or thereabouts. I thought this would be an easy number to locate but I haven’t found it yet. I found plenty of time series data, but that means another area under the curve calculation, with no shortcut this time. Does anyone have an estimate?
2) What is the resulting temperature likely to be? For this one, the IEO2011/RCP8.5 fit seems to be directly relevant. Here’s another one of my annotated AR5 graphs, this one shows the RCP8.5 forcing in 2035. Unless I’m much mistaken, if we follow the IEO2011/RCP8.5 scenario, our forcing will be 3.7 W/m2 by 2035. But now I’m stuck. How do I get from forcing to temperature?
You have failed to grasp the logic of a carbon tariff (be it on China or any other country). If we bear the expense of embracing a carbon-free energy infrastructure and another country does not, we will be at t a competitive disadvantage for doing the right thing. There will be an incentive for countries to move offshore to export goods back to us. The carbon tariff removes that incentive. It is not a punishment, but a leveling of the playing field.
Perhaps a link above “The Bore Hole” called “The Best of Unforced Variations” (or some such) that adds the best question or most insightful explanation from each month to the roll? That would be to encourage better commenting and add a carrot to compliment the stick.
Other than that, as part of the problem I’ll shut up and even resist commenting on what Dan H. is up to now. Note that this is very hard for a recidivist wisenheimer like myself.
Ray Ladbury wrote: “If we bear the expense of embracing a carbon-free energy infrastructure and another country does not, we will be at a competitive disadvantage for doing the right thing.”
If we make the investment in a carbon-free energy infrastructure and another country does not, we will enjoy an enormous competitive advantage over that country for doing the right thing.
Countries that invest in renewable energy now will enjoy the benefits of an endless supply of increasingly less expensive energy, as the cost of wind and solar technology declines and its efficiency increases.
Those that fail to do so will suffer economically as they remain mired in an era of ever more costly, increasingly scarce fossil fuels.
For Chris Dudley: yes, I’ve done some reading.
Attribution — the science:
Particularly the 2011 and 2012 topics.
Yes, we know burning fossil fuel adds to warming and probably to more extreme conditions.
Consider the range of natural variability — for drought and for extreme rainfall events.
The answer to “somebody’s gotta pay for this!” is — yes.
I agree that the countries that embrace renewables–if, indeed any do–will have an advantage…eventually. However, building infrastructure is expensive–and building infrastructure over existing and decaying infrastructure even more so.
On september 23 a lot of people in Belgium sang for the climate.
2 links to see : the original clip : https://www.youtube.com/watch?v=c7V1qLLsn7M and the collection of videos : http://www.youtube.com/playlist?list=PLb4xBudD3TCG1nX_U3LkKsTeLmEVFu_L5&feature=plcp
I’ve never made a claim that the collecting of reparations for damage done by recent emissions has anything to do with mitigation. It is a natural consequence of more certain attribution, an advance of climate science. I think mitigation levers were ruled off topic a little ways back. I would repeat though that I think that extension of the Kyoto mechanism gives the most purchase for accomplishing mitigation.
“I think mitigation levers were ruled off topic a little ways back.”
As was political economics, and for that matter, political attribution.
Sorry if it’s bad form but I’m going to take a shot at answering one my own questions @289. I might make a total hash of it, but in my experience there’s no better way to learn.
additional forcing resulting from the period 1750 to 2005: 1.66 W/m2 (“Climate Change, Lines of Evidence” video, chapter 5, at 2:50)
CO2 doubling = 3.7 W/m2 forcing (Wikipedia: Climate sensitivity)
climate sensitivity = 0.8ºC, hence CO2 doubling = ~3ºC increase (ibid.)
temperature increase resulting from the period 1750 to 2005: 1.66 W/m2 * 0.8 = 1.33ºC
forcing increase if we follow RCP8.5 from 2009 to 2035: 1.5 W/m2 (see my annotated AR5 forcing chart)
temperature increase if we follow RCP8.5 from 2009 to 2035: 1.5 W/m2 * 0.8 = 1.2ºC
1.33ºC + 1.2ºC = 2.53ºC by 2035 if we add 1,000 Gt of CO2 between 2009 and 2035
Hopefully this is an overestimate! I’m skipping from 2005 to 2009, but that’s pretty minor. My temperature increase for 2009 to 2034 could be an overestimate, because the forcing actually varies continuously over time. It’s the area under the curve again, right? If so, it should be easy to fix since the curve is actually a line in this case.
OK, so how did I do?
Re Chris Dudley – if you did want to make a case for that (Kyoto) you might perhaps elaborate here http://scienceblogs.com/stoat/2012/06/25/carbon-tax-watch/ and perhaps I might respond there (if the host doesn’t get to it first?).
Yesterday the Arctic sea ice extent was 4,662,344 sq km. The recovery over the last seven days has not been super speedy. So, in order to recover to the average sea ice extent from the prior ten years on Oct 28 when recovery tracks have converged, the needed recovery rate from now until then has to be 3% higher than the fastest 7 day recovery rate in the prior period. We can expect either a bat-out-of-hell recovery rate over the next 19 days or a delay past Oct 28 for convergence.
While it is fun to write “bat-out-of-hell,” there is some spread for the sea ice extent on Oct 28 in the last ten years. If we count convergence as reaching the lowest value rather than the average, the required recovery rate is a factor of 1.18 lower than the fastest 7 day recovery rate in the prior ten years. And, 2007 and 2011 did kind of squeak into convergence that way and did not start to twine into middle of the pack until November. http://www.ijis.iarc.uaf.edu/seaice/extent/Sea_Ice_Extent_prev_L.png
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