This month’s open thread. In honour of today’s New York Marathon, we are expecting the fastest of you to read and digest the final IPCC Synthesis report in sub-3 hours. For those who didn’t keep up with the IPCC training regime, the Summary for Policy Makers provides a more accessible target.
Also in the news, follow #ArcticCircle2014 for some great info on the Arctic Circle meeting in Iceland.
Oh–and I’ve put up a Care2 petition to thank the President for this action. A convenient way to show a little support for constructive action:
http://www.thepetitionsite.com/922/060/150/thank-president-obama-for-the-agreement-with-china-to-cut-greenhouse-gas-emissions/
184/5 Meow. I always recommend RC’s “Start Here” but also include the “History of Climate Science” and “Newcomers Start Here” over at Skeptical Science as other good resources. Another couple good sites are at The American Physical Society and The American Institute of Physics.
#72 Edward G: “If I got you wrong, I am still interested in the psychology, not the mitigation. There may be no answer.”
I’m interested in measurement and management of safety. Offline from RC, of course. email me at jonk at infinitefactors dot org, if so.
Any thoughts on this current wave of cold Arctic air that is sweeping the nation. I figure it’s a result of warm ocean currents traveling further Northward allowing tropical hurricanes to become Extra-tropical but I don’t know. I heard Michio Kaku on one of the morning shows telling the viewing audience to get used to it because the climate is changing. That was all he said. No real mention of Climate Change as being the cause.
Is there any analysis available that explains our current situation? I’m sure the denier crowd will claim this is proof that Climate Change is a hoax but I would like to know more about why this is happening and what if any links there are to this invasion of Arctic cold and Climate Change. I’m also wondering if this indicates we’re in for another rough Winter season overall?
Thanks.
Any comments here on the new Chinese commitment to cap their CO2 emissions in the year 2030?
Further to the comments @185 & @190.
The “Untrusted Connection” links on the RealClimate Start Here page linking to the IPCC AR4 FAQ (That is the links – ‘here’ ‘PDF’ and to the individual questions) can be avoided using this link here which also yields URLs for the individual questions.
Of course, AR5 has its own set of FAQs but, as published by the IPCC, they are buried in a 78 page PDF. While there are 50% more questions than in AR4, the AR% document has become perhaps a little too grandiose, with 13 pages of preface & titles before the first question is posed. And looking at the questions themselves, are they now appropriate for “Start Here”? I would suggest myself that there are quite a few which are certainly inappropriate, beginning with FAQ 1.1.
FAQ 1.1
If Understanding of the Climate System Has Increased, Why Hasn’t the Range of Temperature Projections Been Reduced?
FAQ 2.1
How Do We Know the World Has Warmed?
FAQ 2.2
Have There Been Any Changes in Climate Extremes?
FAQ 3.1
Is the Ocean Warming?
FAQ 3.2
Is There Evidence for Changes in the Earth’s Water Cycle?
FAQ 3.3
How Does Anthropogenic Ocean Acidification Relate to Climate Change?
FAQ 4.1
How Is Sea Ice Changing in the Arctic and Antarctic?
FAQ 4.2
Are Glaciers in Mountain Regions Disappearing?
FAQ 5.1
Is the Sun a Major Driver of Recent Changes in Climate?
FAQ 5.2
How Unusual is the Current Sea Level Rate of Change?
FAQ 6.1
Could Rapid Release of Methane and Carbon Dioxide from Thawing Permafrost or Ocean Warming Substantially Increase Warming?
FAQ 6.2
What Happens to Carbon Dioxide After It Is Emitted into the Atmosphere?
FAQ 7.1
How Do Clouds Affect Climate and Climate Change?
FAQ 7.2
How Do Aerosols Affect Climate and Climate Change?
FAQ 7.3
Could Geoengineering Counteract Climate Change and What Side Effects Might Occur?
FAQ 8.1
How Important Is Water Vapour to Climate Change?
FAQ 8.2
Do Improvements in Air Quality Have an Effect on Climate Change?
FAQ 9.1
Are Climate Models Getting Better, and How Would We Know?
FAQ 10.1
Climate Is Always Changing. How Do We Determine the Causes of Observed Changes?
FAQ 10.2
When Will Human Influences on Climate Become Obvious on Local Scales?
FAQ 11.1
If You Cannot Predict the Weather Next Month, How Can You Predict Climate for the Coming Decade?
FAQ 11.2
How Do Volcanic Eruptions Affect Climate and Our Ability to Predict Climate?
FAQ 12.1
Why Are So Many Models and Scenarios Used to Project Climate Change?
FAQ 12.2
How Will the Earth’s Water Cycle Change?
FAQ 12.3
What Would Happen to Future Climate if We Stopped Emissions Today?
FAQ 13.1
Why Does Local Sea Level Change Differ from the Global Average?
FAQ 13.2
Will the Greenland and Antarctic Ice Sheets Contribute to Sea Level Change over the Rest of the Century?
FAQ 14.1
How is Climate Change Affecting Monsoons?
FAQ 14.2
How Are Future Projections in Regional Climate Related to Projections of Global Means?
Hi all,
I am an engineering student well acquainted with the science of AGW. I have been a regular reader both here and on SkS for almost a year and just last weekend read through the entirety of Weart’s web page on the history of CO2 research. However there is one point I’ve seen made over and over but never really justified, and that is that current temperature / CO2 increases are unprecedented over 800 kyr. On the surface it seems like a fair point — I have a copy of NOAA’s ice core composite data going back 800 kyr and the past century is indeed unique on that time frame within the data. But the resolution in the ice cores is not great — the average difference between 2 points is around 700 years. Since the current trends are only about 100 years in length, who is to say that there wasn’t a similar trend in the past that was simply not revealed in the ice core data? Anybody have any pointers?
(by the way, I had a lot of trouble posting this due to the spam filter blocking my first email address (live))
#205 re “That was all he said. No real mention of Climate Change as being the cause.”
Probably because “climate change” is NOT the cause for “the climate is changing.”
It is the “result” of the Cause.
Action = Reaction = Reaction = Reaction …. you wanna buy some cheap land in
Syria or Libya? Got heaps … going cheap!
Then there is semantics of course, and the ever present imminent danger of
communicating with other human beings. :-)
Chuck Hughes, from
https://www.google.com/search?q=“arctic+air”+”california+drought”+”Pacific+ocean”+”high+pressure”
http://blogs.discovermagazine.com/imageo/2014/04/17/california-drought-midwest-chill-tied-to-climate-change/
That cites:
Wang, S.-Y., L. Hipps, R. R. Gillies, and J.-H. Yoon (2014), Probable causes of the abnormal ridge accompanying the 2013–2014 California drought: ENSO precursor and anthropogenic warming footprint, Geophys. Res. Lett., 41, 3220–3226, doi:10.1002/2014GL059748.
194 Dan Miller and Jon Kirwan: “we should look at religions to see how they are successful in getting people to believe in something and act on that belief.”
“Believe” is a very bad word. I thought you would have stopped using the word “believe” when you took your Prob&Stat course. Almost everybody who has not taken a degree in a hard science has a very mistaken idea about why scientists resist so strongly such words as “believe,” “certain,” “sure” and other words that people want the scientists to say. This is a wall against communication. The required course is very difficult but transformative. The physics department’s probability and statistics course transforms the student into a different person. Correct communication from scientists to the public is necessary for civilization to survive the half century we are in now.
So I can’t go along with a program of getting people to “believe.” “Believe” is something you do to religion. Advocating belief is advocating religion. We have levels of confidence expressed in %, never beliefs. Now you know why I said George Marshall wants to make climate science into religion.
“as George points out, people make decisions based on emotions, not data”
Roger that. And that is a problem.
“There should be a separate discussion on Marshall’s book here on RealClimate.”
Roger that as well. I have advocated that RC should have social scientists as contributors as well as climate scientists.
So again: RC; Please add social scientists to your group. We need them. We need articles from social scientists.
#205–OK, I’ll bite. Yes, I think that this is extremely significant. The announcements imply non-trivial savings in emissions, as a quickie analysis shows:
http://thinkprogress.org/climate/2014/11/12/3591354/us-china-energy-climate-gamechanger/
In addition, according to the Administration fact sheet, the Chinese commitment to the renewable energy target requires a lot of action–I would say, ‘starting NOW’, but the reality is that a lot of this was already well underway, which is probably why President Xi felt comfortable enough to make the commitment he did:
China has followed through on the existing policy, which is to reduce carbon *intensity*, and for good self-interested reasons. In addition to the fact that there is a strong climatic downside for China in projected climate change impacts–the nation is already seriously water-stressed, and under warming, North China is expected to dry further–the air pollution problem already kills nearly half a million Chinese a year, reducing life expectancy in the worst areas by five years on average, and costs the Chinese economy billions of dollars yearly in lost productivity and the like. Perhaps worst from the perspective of the Party is that this is a significant source of citizen discontent with the government.
Moreover, China can no longer supply her coal consumption domestically, and feels quite differently about coal, apparently, now that money spent on it flows increasingly into Indonesian or Australian pockets. And, as in US sentiment around oil, it’s not only the money, it’s also the political consequences of energy dependence. So there are important co-benefits for China in this agreement.
But the really important aspect of this is that Obama and Xi are signaling a very different stance in the negotiations of the nations taking part in the annual Conferences of the Parties–the ‘climate treaty process,’ to call it so. The next COP opens in (IIRC) Lima in just a couple of weeks. But everyone is looking ahead to Paris in 2015, which is when the long-awaited international successor to the Kyoto Protocol is to be signed. Cynicism is easy in this context, given how much failure there has been. But another fiasco like Copenhagen (2009) would be a really grave blow to all remaining hopes of staying under 2 C warming. The agreement we’re talking about here is a big push to avoid that catastrophe by negating one of the biggest obstructionist talking points, and apparently succeeds in getting the ‘camel’s nose into the tent’ for emissions commitments on the part of developing nations. Now if we can only get Narendra Modi on board… there’s some hope for that; India is going big on solar PV right now.
That’s why I’m so thankful to see this diplomatic coup. If you feel similarly, I invite you to join me in telling the President so. It may be a bit corny, but heck, why not put your name on the record? (And, FWIW, this is the only ‘thank you’ project of the three that I’m aware of that doesn’t route you to a donation page after you sign!)
…and, at the risk of provoking passing obstructionists, who always go ballistic at the mention of The Name, Al Gore apparently thinks so, too:
http://climaterealityproject.org/blog/al-gore-joint-us-china-climate-announcement
#204–Yes, Chuck. It seems that this is the latest iteration of a pattern folks were calling ‘WACC’ a couple of years back. That’s an acronym for “Warm Arctic, Cold Continents”–though I guess this iteration, like much of last winter’s, deserves an asterisk, since it’s really just a big chunk of one continent (North America, as you note) that is cold. The good old Climate Reanalyzer (University of Maine) affords a good overview:
http://cci-reanalyzer.org/DailySummary/
As you can see, the really cold part of North America is nicely balanced by an equally warm area, nearly as large, centered on the Beaufort Sea. And most of the Arctic is showing positive temperature anomalies, as well, as is most of Europe and Russia, plus large swathes of Africa. The mean anomaly for the Northern Hemisphere as a whole is 0.80 C, which is pretty toasty on a ’79-2000 baseline. The Southern hemisphere is actually pretty close to baseline, for a global average of 0.43 C. So, in sum, the world is not ‘cool’, let alone cold.
As to the WACC pattern, there has been research linking it to disturbances in the jet stream that are possibly connected to anthropogenic climate change, but the scientific jury is still out on that idea, with active research underway. (That’s the case, at least as far as I know, but perhaps someone will update us on that question.)
And I’d add that I’ve seen or heard meteorological opinion that the current ‘jag’ in the NA jet stream is due mostly to the remnants of Typhoon Nuri, which became extratropical and set intensity records. It hit the Arctic in just that Beaufort Sea area where the Reanalyzer image shows that warm patch. Dr. Spencer blogged about it, back at the beginning of the month:
http://www.drroyspencer.com/2014/11/super-typhoon-nuri-to-become-a-bering-sea-bomb/
Unfortunately, he now seems to be sedulously ignoring it in order to trumpet the cold spell and PDO and generally welcome this fresh ‘indication’ of cooling, just along the lines you predicted, Chuck.
Naively, you’d think that this would result in a negative feedback (i.e.. be a cooling influence overall) since the poles are the most important areas for OLR, and warmer poles should mean greater radiative efficacy there. But if we get more water vapor and the far IR window closes significantly, as Hank discussed above, then that is a countervailing feedback. Quantitative analysis needed… and methinks it’s not a trivial task.
Despite huge projected increases in renewable energy, and regionally significant increases in nuclear energy, the IEA’s central scenario is not all that cheery from an emissions perspective:
http://www.iea.org/newsroomandevents/pressreleases/2014/november/signs-of-stress-must-not-be-ignored-iea-warns-in-its-new-world-energy-outlook.html
Chris Dudley:
Maybe. OTOH, you may have mistaken your opinion for well-supported argument. Unless you have submitted your arguments for publication, and have had them accepted after review by recognized experts, then your comments on this blog are merely your opinion. A search for “Dudley climate policy” on Google Scholar turned up nothing recognizable as yours. Did I miss it?
AntonyIndia wrote: “Any comments here on the new Chinese commitment to cap their CO2 emissions in the year 2030?”
The announced agreement falls far short of what is needed to avert the worst effects of global warming, and far short of what both the USA and China could easily accomplish — and it is more than either country’s government has previously been willing to agree to do.
Chuck Hughes wrote: “I’m also wondering if this indicates we’re in for another rough Winter season overall?”
Who do you mean by “we”? And what do you mean by “another rough Winter season”?
According to the U.S. National Climatic Data Center, last winter (December 2013 to February 2014) was the 8th warmest winter ever recorded globally. In Finland, February 2013 was the second-warmest February ever recorded. Scandinavia, Russia and Alaska had extremely warm winters.
The “lower 48” in the USA had a cold winter — but only the 34th coldest in the last 119 years, nowhere near a record.
Mann v. Steyn hostilities are scheduled to commence in ~ 48 hours.
Lightning expected to increase by 50 percent with global warming
http://www.sciencedaily.com/releases/2014/11/141113142112.htm
and so more wildfires.
The charge of lying to the SEC is interesting here. In the context of divestment, many fossil fuel companies may be doing that right now.
“Don Blankenship, the longtime chief executive officer of Massey Energy, was indicted Thursday on charges that he violated federal mine safety laws at the company’s Upper Big Branch Mine prior to an April 2010 explosion that killed 29 miners.
A federal grand jury in Charleston charged Blankenship with conspiring to cause routine and willful violations of mandatory federal mine safety and health standards at Upper Big Branch between Jan. 1, 2008, and April 9, 2010, U.S. Attorney Booth Goodwin said.
The four-count indictment, filed in U.S. District Court, also alleges that Blankenship was part of a conspiracy to cover up mine safety violations and hinder federal enforcement efforts by providing advance warning of government inspections. The indictment also alleges that, after the explosion, Blankenship made false statements to the U.S. Securities and Exchange Commission about Massey’s safety practices before the explosion.” http://www.wvgazette.com/article/20141113/GZ01/141119629/1104
Some of the recent agreement with China is interesting in terms of cooperation which may accelerate China achieving its commitment. I notice that the University of Kentucky has some facilities that might be helpful. http://www.caer.uky.edu/powergen/home.shtml
Are there others?
October tied with October 2005 as warmest. http://data.giss.nasa.gov/gistemp/tabledata_v3/GLB.Ts+dSST.txt
Dan (#195),
A fee or tax is least effective for petroleum (because it is so much more expensive than coal or gas). The US uses CAFE standards and biofuel requirements as well as rebates for PHEVs and BEVs to attach that problem. So, if you want to lay a fee on top of existing or written regulations, it is not at all clear that that is more effective than just cranking up the requirements of the regulations themselves. The Clean Air Act requires that if the danger becomes more acute.
in response to #204, see
http://www.slate.com/blogs/future_tense/2014/11/10/the_omega_block_your_wintry_companion_for_at_least_the_next_two_weeks.html
> Jon Keller
> Since the current trends are only about 100 years in length,
> who is to say that there wasn’t a similar trend in the past …
Hmmm, the Advanced Search at Weart’s AIP site is giving me
So I’m not positive what you read, but I’ll wing it ’til someone knowledgeable comes along to answer you or the search works.
You say that for ice cores he describes a 700 year resolution (where is that in the document, since search isn’t working? I’m not sure that’s the best resolution available anywhere to date)
The rapid increase over the past century or three (see Ruddiman for longer time spans) is attributed to fossil fuel burning, by the isotope test among much else. Do you think natural CO2 spikes at the same rate of increase are possible
That would mean both increase and decrease totaling less than 700 year resolution, which wouldn’t show up in ice cores.
Is that what you’re thinking?
But do you see any way that such a CO2 spike could _decrease_ again, a total excursion within 700 years, so not appear in the ice cores or elsewhere?
If nature can remove a mass of CO2 so rapidly somehow then we’re saved — but I don’t think anyone has suggested such a possibility exists.
They say God is in the gaps, and so is Gaia (it gets crowded in the gaps, though, as research makes the gaps smaller and smaller).
I think I recall much higher resolution ice cores recently, or ocean sediment cores, that would cut the gaps down even further.
http://io9.com/scientists-have-climbed-to-the-bottom-of-the-mysterious-1658817496
That hole in Siberia? They’ve done that.
News once they analyze their data.
Things are getting sticky in Mann v. Steyn!
@13 Nov 2014 @ 8:07 AM:
1. The dramatic change in atmospheric CO2 concentrations since pre-industrial are driven by known processes, not of natural origin.
2. Assuming, for the sake of argument, that dramatic changes in CO2 are a purely random process (which there is no reason to think), and further assuming 700y average spacing between samples, and 100y dramatic excursions, what’s the probability that no such excursion will be caught in 800,000/700=1143 samples?
..
More ‘scorchio!’
GISS global temperature for October is equal hottest on record for October.
GISStemp now joins HadCRUT & NCDC with its ‘average for year-to-date’ for 2014 hotter than highest annual figure on record (although it remains below the ‘average year-to-October’ of 2010).
Thanks to those here who’ve taken a moment to go on record in support of US-China emissions agreement by signing the ‘petition of thanks’ I started. (A few days in, we’re at ~200 signatures, and with the accord dropping out of the news cycle, it’s gotten slow. So if you missed it, please consider joining the ‘regulars’ who’ve taken a moment to express appreciation–and maybe hand a tiny talking point to help nobble the obstructionists, who certainly haven’t given up, as demonstrated by renewed squawking and yet another money-wasting ‘symbolic’ vote for Keystone XL.)
Digressing…
Anyway, thanks again to those who acted. Favorite comment so far (you know who you are!):
Yes, indeed.
Petition link:
http://www.thepetitionsite.com/922/060/150/thank-president-obama-for-the-agreement-with-china-to-cut-greenhouse-gas-emissions/
#207 Jon Keller
I´m not an expert, but my opinion is as follows.
Apart from big meteorite collisions and huge volcanic eruptions, natural causes don´t produce meaningful changes just for a few centuries…
The ocurrence of those phenomena is something pretty well known.
Could have there been some not detected “medium size” of those phenomena? Most probably, I guess.
But, in my opinion, a possible, short term higher temperature / CO2 increases due to such a type of phenomena doesn´t mean we shouldn´t say that “current temperature / CO2 increases are unprecedented over 800 kyr …
Currently we use humankind time scale, but if we compare with a 800 kyr period, I consider we should make kind of time scale switch. “700 yr is nothing” … (a famous argentinian tango says that for 20 yr)
Hailstone microbiology:
Alexander B. Michaud et al: Biological ice nucleation initializes hailstone formation. Journal of Geophysical Research: Atmospheres 2014; DOI 10.1002/2014JD022004.
Another possible (biological) feedback with climate change?
#217,
You did. It is always amusing when an anonymous internet poster starts banging on about credentials. But you can find policy work I contributed to here: http://www.gp.org/earth-day-2006 Other work is described in Bill McKibben’s book “Fight Global Warming Now!” http://billmckibben.com/fightglobalwarmingnow/index.html
I should acknowledge that the problem revenue associated with the carbon tax was brought home to me most clearly in discussions with Steny Hoyer, then House Majority Leader.
If you want a carbon tax, you’ll have to address that to get much support in congress. Fee and dividend does address that issue, but it involves a large distribution bureaucracy which may run into privacy issues.
The longer I look at it, the more it looks like a scythe to me:
http://img.qz.com/2013/12/temperature_record-wheelchair.png?w=640
RE 217 In the UK the period Dec 2013-Feb 2014 was the warmest on record.
Re: #210 Edward Greisch: 194 Dan Miller and Jon Kirwan: “we should look at religions to see how they are successful in getting people to believe in something and act on that belief.”
Please do NOT include my name in a quote which has NOTHING to do with me. I don’t appreciate the conflation.
As a side note, thanks for writing personally. I had hoped differently, but it appears you aren’t interesed in engaging a discussion dealing with specific issues at all. Instead, just expressing your strong opinions to anyone who might dare listen. I personally understand much better now the RC policy about mitigation discussions. I was more naïve, before.
An interesting and completely irrelevant report on what weather sounds like on Language Log. See it HERE.
http://www.reportingclimatescience.com/news-stories/article/nasa-alaska-shows-no-signs-of-rising-arctic-methane.html
Baseline, finally, established.
Watch the methane monster sites to see how this gets spun into fear about what happens next, of course.
I’ll be curious to see how they explain the observations thus far.
http://newsoffice.mit.edu/2014/www.pnas.org/cgi/doi/10.1073/pnas.1412190111
hat tip to Reddit http://www.reddit.com/tb/2mesl9 for this MIT press release, in all its PR department language glory:
#225 Hank Roberts, #228 Meow, #231 Rafael Molina, thank you for your responses.
#225 Hank Roberts: I didn’t get the 700 year figure from Weart, I used “EPICA Dome C Ice Core 800KYr Carbon Dioxide Data” from NCDC and the temperature data from the same source. I calculated the average difference between points in the data. I do not question that CO2 increases are attributable to human emissions, and moreover whether a more natural ‘sudden change’ happened in the past really doesn’t change what we know about what is happening now. I’m really just asking out of interested curiosity where the “unprecedented” claim came from and how it is backed up by the science.
You make a good point about how both the rise and the decline would have to happen in between two data points in order for it to not show. But I think it would be possible, if only 20% of a sudden increase remains after 300 years. http://www.yaleclimateconnections.org/2010/12/common-climate-misconceptions-atmospheric-carbon-dioxide/
If you could point me toward higher resolution data it would be much appreciated.
#228 Meow: Again, I am aware that the recent CO2 increases are anthropogenic. If a sudden change happened in the past, it wouldn’t have to be random, there would of course be a cause and it would be up to the scientific community to find it. The probability argument doesn’t really apply because it would only take one dramatic change in the past 800,000 yr to render the ‘unprecedented’ claim false.
#231 Rafael Molina: So scientists are not aware of any natural phenomenon that could in theory produce a sudden change, and that in addition to the data leads to the conclusion that it is unprecedented. But that conclusion is based on the assumption that the scientists are aware of all possible natural CO2 phenomena and know precisely how they operate. So it’s built on a sort of shaky foundation. If that really is all the evidence we have then a more fair claim would be “to the best of our knowledge, it is unprecedented” because it leaves the door open to the possibility that we just missed something.
“But, in my opinion, a possible, short term higher temperature / CO2 increases due to such a type of phenomena doesn´t mean we shouldn´t say that “current temperature / CO2 increases are unprecedented over 800 kyr …
Currently we use humankind time scale, but if we compare with a 800 kyr period, I consider we should make kind of time scale switch.”
But if it was possible wouldn’t the claim be a bit disingenuous?
I’ve also seen claims that current rates of increase are unprecendented, which would be similarly hard to actually prove with a high degree of certainty (actually probably harder).
So there is no paper or definite evidence to solidly back up the claim? Lack of evidence that it has happened isn’t very strong evidence that is hasn’t.
RE:”Researchers show that a canonical view of global warming tells only half the story”. What I want to know is if this finding supports Dr. Trenberth’s work on differentiating models into two groups depending on how they generate clouds. Where he found that this also reflected whether the models generated a low or high equilibrium temperature.
Hank,
That would be the baseline only for Alaska, right? Not for the ESAS.
Hank (#239),
Here is another spot to look. http://www.atmos.washington.edu/~angie/donohoearmourpendergrassbattistiPNAS.pdf
What is counter intuitive seems to me to be that when they break things up into long wavelength and short wavelength, the smaller short wavelength effect is claimed to be the larger cause of warming. I think that comes from this claim:
“For all times after
τcross, energy is lost through enhanced LW emission, and energy
accumulation is solely due to enhanced ASR.”
which asserts that recovery to preindustrial infrared emission from the top of the atmosphere is the proper dividing point for separating the two effects. However, the greenhouse effect still acts on albedo change effects and the long wavelength forcing is a part of that, so their dividing line may not be the best approach and may contribute to their claim that this in counter intuitive.
Jon Keller @240.
Your original comment @207 set out the “claim” you are enquiring about as follows –
I’m not entirely sure what you meant by this statement. Now @240 you bandy words about “the claim” and I am even less clear what you mean.
In anticipation of some clarity, I will offer the following.
The “unprecedented” label is easily attached to the CO2 record of the last 150 years when compared with the last 800ky and that label is used over and over and over.
The “unprecedented” label for temperature is not usually attached to the 800ky time scale, rather to the millennial timescale. Although some uses of the “unprecedented” label may be used more broadly than just CO2 (& methane) and extend beyond the 1ky to attach to longer periods (eg. 500ky), they can still remain well founded.
I’m sure if I look about the web, an “unprecedented” label for temperature alone cold be uncovered but to be well-founded I would expect it to be of a strongly nuanced form. And there is often purpose to such ‘labelling’. Do be mindful that the rate of change of temperature and thus climate today can be considered very high when compared with the rate of change of previous climate changes like the PETM or the last deglaciation.
For Jon Keller, here’s discussion of one such report:
https://www.sciencemag.org/content/321/5889/680/reply
“The main purpose of the paper is to present a new high-resolution data set that can advance our understanding of the climate system and of abrupt changes. …”
I just ‘oogled: high resolution ice core data
You’ll find more; somewhere there’s a complete archive. I recall Gavin commenting some years ago after a trip to China that the big problem with this is each drilling site tends to have its local information but the field needed a serious effort at cross correlating the data sets. I think that’s been happening.
#240–Jon, I think you are drastically overestimating the uncertainty. Faster rates of CO2 release may be possible–though, to my recollection, rates even during the PETM, perhaps the worst CO2-driven disaster in the paleo record, were lower than today’s, though the ultimate CO2 release was massive–but it’s pretty hard to imagine anything that would accelerate the drawdown of CO2 to the kinds of rates that would be needed. We know that CO2 is absorbed by seawater, and taken up by organisms on land and in the sea, but that real sequestration operates largely by the weathering of siliceous rock. The last is negligible on sub-millennial time scales, and the former two would need to be accelerated quite a bit from what we see today to dispose of today’s CO2 pulse in just a couple of centuries.
So, other than pixie dust, what could possibly do that? It’s hard to prove a negative, all right, but is there even a conceivable candidate mechanism anywhere in sight?
Tony, that report on Alaska
is the only area studied for publication, so far, I think.
Research Letter
Four corners: The largest US methane anomaly viewed from space
Eric A. Kort1, et al.
Article first published online: 9 OCT 2014
DOI: 10.1002/2014GL06150
Geophysical Research Letters
Volume 41, Issue 19, pages 6898–6903, 16 October 2014
http://www.nasa.gov/press/2014/october/satellite-data-shows-us-methane-hot-spot-bigger-than-expected/
Note the useful CrossMark service is now available — finding updates to published work:
http://crossmark.crossref.org/dialog/?doi=10.1073/pnas.1412190111&domain=pdf&date_stamp=2014-11-05
This is the result for that article:
Published online before print November 3, 2014,
doi: 10.1073/pnas.1415631111
PNAS November 3, 2014
http://www.pnas.org/content/early/2014/10/29/1415631111
Disentangling the effects of CO2 and short-lived climate forcer mitigation
Measures reducing short-lived climate forcers are complementary to CO2 mitigation, but neglecting linkages leads to overestimating their climate benefits.
Abstract
Anthropogenic global warming is driven by emissions of a wide variety of radiative forcers ranging from very short-lived climate forcers (SLCFs), like black carbon, to very long-lived, like CO2. These species are often released from common sources and are therefore intricately linked. However, for reasons of simplification, this CO2–SLCF linkage was often disregarded in long-term projections of earlier studies. Here we explicitly account for CO2–SLCF linkages and show that the short- and long-term climate effects of many SLCF measures consistently become smaller in scenarios that keep warming to below 2 °C relative to preindustrial levels. Although long-term mitigation of methane and hydrofluorocarbons are integral parts of 2 °C scenarios, early action on these species mainly influences near-term temperatures and brings small benefits for limiting maximum warming relative to comparable reductions taking place later. Furthermore, we find that maximum 21st-century warming in 2 °C-consistent scenarios is largely unaffected by additional black-carbon-related measures because key emission sources are already phased-out through CO2 mitigation. Our study demonstrates the importance of coherently considering CO2–SLCF coevolutions. Failing to do so leads to strongly and consistently overestimating the effect of SLCF measures in climate stabilization scenarios. Our results reinforce that SLCF measures are to be considered complementary rather than a substitute for early and stringent CO2 mitigation. Near-term SLCF measures do not allow for more time for CO2 mitigation. We disentangle and resolve the distinct benefits across different species and therewith facilitate an integrated strategy for mitigating both short and long-term climate change.