30 Sep 2013: Analysis

Has the U.N. Climate Panel
Now Outlived Its Usefulness?

Some scientists are saying the latest report from the Intergovernmental Panel on Climate Change is overly conservative and fails to mention some of the most worrisome possible scenarios. The panel, they contend, is no longer fulfilling its mission of informing policy makers of the risks of global warming.

by fred pearce

After four years of work, it took the U.N. Intergovernmental Panel on Climate Change until 5 a.m. on the morning of publication last Friday to agree on the final wording of its new report. Agreement was only reached at the end of an all-night closed session at which delegates from governments cross-questioned the scientists and at times sought to put their own spin on the findings. It is not called an “intergovernmental panel” for nothing, and every last nation had to agree to the text before it was published.

So is this science or politics?

Leaving aside the hysterical fringes, most mainstream media coverage of the IPCC report took one of two lines. Some concentrated on its "stark warning" about how scientists are "more sure than ever" about climate change and humanity’s role in it. Others more skeptically stressed that the panel had confirmed for the first time a slowdown in warming in the past 15 years, and that, partly as a result, it had slightly lowered its projections of future warming.

Both stories are true. As Thomas Stocker of the University of Bern, the co-chair of the scientists behind the report, put it at the press launch: "Human influence on the climate is clear," and "climate change is the greatest challenge of our time." The assessment had concluded that scientists are
Some ‘scary scenarios’ has been left out of the model projections on which the IPCC’s forecasts are based.
now 95 percent certain that the warming since 1950 is due primarily to human activity, up from 90 percent in their last report in 2007.

Yet Stocker also talked about scientific interest in what lay behind what he termed the "hiatus" in warming. Nobody, the report says, is yet sure whether it is a blip — perhaps caused by some natural redistribution of heat between the atmosphere and the oceans — or whether it means climate models have got something wrong about global warming.

But there is a third narrative about the IPCC that has received less attention. Some of those involved in the report process believe the natural caution among scientists — coupled perhaps with a wish not to repeat some exaggerations that marred some previous IPCC reports, and the effect of politicians looking over their shoulders — has created a report that is overly conservative, even biased, in its conclusions. Rather than lowering its expectations of warming, these scientists say, perhaps the panel should be raising them.

Some "scary scenarios" arising from possible positive feedbacks — in which nature amplifies man-made warming — have been left out of the model projections on which the IPCC’s headline forecasts are based. Surely, some critics say, it is the scary scenarios that politicians need to know about if they are to do their duty under the UN climate change convention and act together to prevent "dangerous climate change." Even the U.S. signed that, under George Bush senior in 1992.

The report’s headline conclusions include:

— Global warming is "unequivocal." The last three decades were the warmest in the atmosphere for at least 1,400 years. While atmospheric warming has slackened unexpectedly in the past 15 years, it continues, and warming is unabated in the oceans. This oceanic warming is melting ice on land and at sea, most notably with the dramatic summer declines in Arctic sea ice. The melting of land ice and thermal expansion mean that sea-level


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rise is now twice the average rate before 1993, at over 3 centimeters a decade. This too is unprecedented in recent times.

— The warming slowdown is one reason for a marginal reduction in expected warming over the coming century. Modelers now expect a doubling of greenhouse gas concentrations in the atmosphere to bring warming somewhere between 1.5 and 4.5 degrees Celsius, rather than the between 2 and 4.5 degrees projected last time.

— New research identifies clear evidence of an intensification of the water cycle, with wet areas and seasons becoming wetter, and dry areas and seasons drier. But the IPCC has retreated on some statements made in 2007 that this is creating more droughts, or more hurricanes.

The vast tome, which will come to over 3,000 pages, was written by more than 250 authors, reviewed by over 1,000 other experts, and cites more than 9,000 pieces of peer-reviewed science. And yet, in places, the scientists had to work hard last week to restrict political interference with the findings.

Hence that 5 a.m. finish last Friday. Yale Environment 360 has established that the meeting of scientists and government delegates called to sign off on the report was virtually done at midnight on Thursday, when they got to a final paragraph about something the IPCC had not mentioned in previous reports, but which the scientists felt was hardly contentious.

Their draft of the summary report said that, since much of the carbon dioxide emitted into the air by human activity stays there for many centuries, the warming it produces is "irreversible on a human timescale" — at least without massive geo-engineering. Therefore, if the world is serious about restricting warming to below two degrees Celsius since
One contentious topic was how the report should deal with the recent warming hiatus.
pre-industrial times, it needed in effect to impose a carbon budget. It had to restrict total man-made emissions forever to below about one trillion tons of carbon — or to 800 billion tons if we assume that our emissions of other greenhouse gases are unlikely to halt anytime soon. We are already two-thirds of the way there, at around 530 billion tons.

That was the bald scientific calculation. But three governments in particular objected to this statement. According to sources who attended the meeting, they were China, Brazil and Saudi Arabia. The U.S. was not involved.

The scientists dug in. "I sat for five hours defending this paragraph," said Reto Knutti of ETH Zurich, a Swiss science university, who was the coordinating lead author for the relevant chapter on "projections, commitments, and irreversibility."

"There was very strong opposition from many governments. It was obviously political, though they were using strange scientific arguments," Knutti said. The governments saw this statement as, in effect, scientists imposing emissions restrictions through the back door. "I am proud to say we didn’t lose any figures," he added, "though some of the text was rewritten a bit."

Drew Shindell of NASA’s Goddard Institute for Space Studies, another lead author on the report, was also in the room. "Some people were very sensitive to this cumulative carbon issue," he said. "They had agendas beyond the science."

Another contentious topic was how the report should deal with the recent warming hiatus. The draft acknowledged the scientists' concerns and noted that climate models "do not generally reproduce the observed reduction in surface warming trend over the last 10-15 years." This was reportedly met with opposition from some delegates who wanted to remove all references to a slowdown. Some argued that the hiatus had not lasted long enough to be considered a temperature trend. Perhaps they also felt it would be seized on by climate-change deniers.

"We looked at this very carefully," said Stocker. There was, he noted, "not a lot of published literature" on the phenomenon. This was a problem, since the IPCC does not do its own research and can only review published literature. But again, the authors of that passage stuck to their guns, and retained most of the message, though the direct statement about the failings of the models does not appear in the report.

Science is not naturally a consensual process. Reaching agreement is hard for people more used to spending their time refuting each others' hypotheses. So the question arises: Is the IPCC’s self-imposed task of producing massive consensual documents about every aspect of climate science — and then resisting politicians' efforts to change them — worth it?

For one thing, the consensus even among scientists is creaking. In interviews with Yale Environment 360 in recent weeks, a number of past and present IPCC authors have expressed strong dissatisfaction with what they saw as the conservatism of the emerging text for the scientific
‘I agree there can be a conflict between good science and what policy makers and engineers want to know,’ a report author says.
assessment. (There is, if anything, even more contention over the two companion reports that will be published next year, covering the impacts of climate change and what to do about it.)

Some researchers are angered about the marginal reduction in predicted warming. They say that may be justified by the outputs of the climate models, but that those models do not include some worrying positive feedbacks that could accelerate warming in coming decades. Other critics say that, even though the report has upped its estimates of sea level rise this century to as much as one meter, the lead authors did not accept findings from reputable researchers suggesting that a rise of as much as two meters was possible.

The problem, in essence, is that factors that climatologists cannot yet successfully model are left out of the modeling studies that deliver the headline predictions.

Michael Mann of Penn State University, a past IPCC lead author, is concerned about the sidelining of the potential for higher sea level rises due to collapsing ice sheets on land. Before the report's publication, he said the report "should not be dismissing impacts with lower probability, but higher threat potential. Such potential outcomes are a critical part of the societal risk." For instance, people designing flood risk defenses want to know about the worst expectations of possible sea level rise, not those scientifically most likely.

One lead author of the IPCC chapter on sea level rises, spoken to after the report’s publication, conceded the point. "I agree there can be a conflict between good science and what policymakers and engineers like flood designers want to know," said Tony Payne of the University of Bristol, England.

Another concern is methane, a potent greenhouse gas that could escape into the atmosphere as Arctic permafrost melts and sea beds warm. The methane is the frozen product of rotting vegetation in centuries past. The IPCC estimates that up to 80 percent of the Arctic permafrost could melt this century.

Such methane releases could dramatically accelerate global warming, but the threat is not included in existing climate models, notes Kevin Schaefer of the University of Colorado at Boulder. Schaefer said leaving out the permafrost feedback means that "all climate projections in the [IPCC report] are likely to be biased on the low side."

He says the omissions are not the fault of the scientists writing the report, but of the IPCC’s cumbersome processes. The deadline for including new data in model runs was 2009, whereas "the first estimates of the permafrost [methane] feedback came out in 2011, way too late to include," said Schaefer. But he warned the upshot could be governments setting targets for greenhouse gas emissions that resulted in an "overshoot" of their promise, in Copenhagen in 2009, to cap warming at 2 degrees Celsius.

Nicholas Stern of the London School of Economics, author of an influential economic assessment of climate change for the British government in 2006, takes a similar view about the failings of the IPCC and its models. He
The question is now being asked: Is the IPCC still fit for its purpose?
complained at a meeting at the International Monetary Fund in Washington, D.C., in April that "the scientific models mostly leave out dangerous feedbacks." He called for "a new generation of models [that] focus on understanding probabilities of events with severe consequences for people [rather than] those effects that can be modeled more easily."

For more than two decades, since it was created by the UN in 1988, the IPCC has done the job politicians asked of it: to synthesise scientific thinking around climate change and deliver a series of consensus assessments to policymakers. In the process, the IPCC won the Nobel peace prize in 2007. But the question is now being asked: Is the IPCC still fit for its purpose? It may do good science, but does it deliver what policymakers need?

David Keith, a Harvard University professor who recently resigned as an author of the IPCC report, says "The IPCC is showing typical signs of middle age, including weight gain, a growing rigidity of viewpoint, and overconfidence in its methods. It did a great job in the early days, but it's become ritualized and bureaucratic, issuing big bulk reports that do little to answer the hard questions facing policymakers." It needs, he says, "a reinvention."

The irony may be that the IPCC has stood up to political pressure, and maintained its scientific purity, perhaps just a tad too well.

POSTED ON 30 Sep 2013 IN Climate Climate Policy & Politics Policy & Politics Asia North America 


Fred — thanks for this long-needed overview of the institutional optimism bias of the IPCC. The fact of all governments having a word-by-word veto on its reports adds a further layer of vested interest bias, while most of the media still present the reports as the 'consensus of scientific understanding' — which they clearly aren't.

With regard to the feedbacks, some readers may be unaware of the number, beside the permafrost, that are already accelerating; that many are directly interactive and all are indirectly interactive; and that several have the potential, individually, to dwarf anthro-CO2 outputs.

In order of seniority, they can be listed with observed or inferred start dates as:
Water vapour increase (1820)
Albedo loss due to cryosphere decline (1950)
Ocean acidification and warming (by 1960) cutting its potential carbon sink capacity
Microbial peatbog decay (by 1962) due to raised CO2
Permafrost melt (by 1975)
Forest combustion (by 1982)
Soil desiccation (1990s)
Methyl clathrates (by 2008)

For the IPCC to have failed in all its reports even to show the observed acceleration of these major feedbacks to date, let alone to provide its best estimates of their future growth from the track record, is surely going to be of profound discredit to science as their impacts take off. What is needed is a clear refutation that it is not independent science that is at fault, but its muzzling by the traditional co-option of science to serve governments in private, rather than directly informing the public.


Lewis Cleverdon

Posted by Lewis Cleverdon on 30 Sep 2013

How absurd that Yale could be on such a good track with this article, then ruin it with painful omissions.

There are as many mini-ice-age fears among the top solar scientists as there are warming. See NSO on the next solar cycle, Theodore Landscheidt, Dr. Elliot (Ireland).

Or how about how climate.gov shows a near unchanging solar forcing over hundreds of years, when that is only UV irradiance. X-ray flaring and CMEs are highly more variable, and there is a marked increase in coronal holes and the Alfven waves that come with them. NASA claims earth's magnetosphere is 10 percent weaker than it was in the 19th century, and the WCG for Geomagnetism in Kyoto shows us that it has been weakening for 400 years.

The solar magnetic fields are weakening terribly, but the larger changes are on the other planets. Mars is warming, Venus is slowing rotation and has 25 percent faster winds, Jupiter lost a stripe and has a new red spot, and the 30-year Saturn superstorm was a decade early and lasted longer than we have ever seen.

None of these are my words, obviously. You can seek them out at the ESA, NSO, NASA, and others, or just Google "They Want to Blame You," and I promise you won't believe another word of the IPCC.

None of this precludes the possibility that positive feedback could make us warm tremendously; indeed this report is a bit of a backhand to the IPCC. But this is my retort, from a fellow IPCC dissident.
Posted by Ben Davidson on 30 Sep 2013

Yes, this plotical unit has outlived its usefulness for many of the reasons listed previously. The entire report could have been summed up by the following: Yes, we are really sure it has warmed, and that people are responsible for more than half, and if we keep it up, it will warm further. By the way, we have no clue why it hasn't warmed over the past decade and a half, but trust us, it will.
Posted by Dan B. on 02 Oct 2013

"Some people were very sensitive to this cumulative carbon issue," said Shindell.

This is unsurprising.

What the published 'Summary for Policy Makers' said on this was as follows:

IPCC AR5 WG1 30 09 2013
“Limiting the warming caused by anthropogenic CO2 emissions alone with a probability of:
1. >33%,
2. >50%,
3. >66% ...
... to less than 2°C since the period 1861–1880, will require cumulative CO2 emissions from all anthropogenic sources to stay between...,
1. 0 and about 1560 Giga-tonnes Carbon [Gt C]
2. 0 and about 1210 Gt C, and
3. 0 and about 1000 Gt C,
since that period, respectively.

These upper amounts are reduced to about:
1. 880 Gt C,
2. 840 Gt C,
3. 800 Gt C,
... respectively, when accounting for non-CO2 forcings, as in RCP 2.6.
An amount of 531 [446 to 616] Gt C, was already emitted by 2011.”

1. 349 GtC
2. 309 GtC
3. 269 Gct
are left 'respectively' for this 'budget'.

However, IPCC’s problem is that, "Non-CO2 Forcings in RCP 2.6" [et al] OMIT key effects of feedbacks, so it is actually more urgent than these figures suggest, if the 2 degree limit is still relevant to UNFCCC-compliance: http://www.gci.org.uk/Documents/IPCC_AR5_WG1_Final_Under-Estimate.pdf

If it is still relevant, it goes beyond being a scientific dispute to being a policy-imperative, where 'politics' takes over, versus 'the precautionary principle' (don't take risks you can't afford to run).

What is needed is credible (quantitative) trend projections of that, i.e. 'inclusive of feedback effects,' and risk-averse policy formulation based on that.

This danger of runaway (self-propagating rates of) climate change is real. So this report is remiss for failing to properly recognize that due to the omission of such feedback effects from the climate models:

Posted by Aubrey Meyer on 02 Oct 2013

Hello Aubrey. Point well taken. The disturbing thing about all of this discussion is quite similar to the national debt and national budget gridlock that results in a US government shutdown too frequently of late that will lead to an adoption of China's monetary unit as the international monetary standard. Finger pointing and arguing our way into a climate change tipping point on top of international bankruptcy and insolvency of many nations simultaneously. Confronting the inconvenient truth is the only way to avoid a greater unpleasant inevitability. We will need to reduce emissions and attend to chemical spills and discharges as necessary to mitigate climate change and eventually develop a safe and sane geoengineering technology to mitigate the natural cyclic events collectively known and referred to as climate change.
Posted by Jessee McBroom on 03 Oct 2013

Jessee, given that you are contradicting all the world's great scientific academies, it is sheer anti-science denialist nonsense to claim that the climate change we face is a "natural cyclic event."

Moreover, there is no rationale for the use of geoengineering techniques without first committing to a binding global emissions treaty to terminate GHG emissions. Without ending BAU outputs there is no feasible prospect of geoengineering keeping pace either to control global temperature or reduce airborne carbon.

Posted by Lewis Cleverdon on 03 Oct 2013

'Doing the maths' on what IPCC AR5 finally published on 'carbon-budgeting' makes salutary reading. The UK Climate Act has negligible chance of keeping within 2 degrees (as CBAT use shows): http://www.gci.org.uk/CBAT/cbat-domains/Domains.swf

Here's a memo that counts & illustrates that: http://www.gci.org.uk/Documents/IPCC_AR5_Odds_for_2_degrees_if_616_GtC_already_emitted.pdf

The UK Parliament doesn't seem to have quite grasped this yet.
Posted by Aubrey Meyer on 07 Oct 2013

Regardless of what the U.K. does, the chances of exceeding 2 degrees this century are rather slim. Temperature rise would need to accelerate to at least double the 20th century rate for that to occur. While this is certainly possible, it is not likely, especially given the recent positive natural boost. The IPCC made a rather nebulous statement that mankind contributed ~0.3 degrees C of warming over the past half century, with the rest being natural. Many scientists are predicting that natural contribution will shift into reverse in the foreseeable future, although the extent is highly variable. I guess that is our best prediction.
Posted by Dan B. on 08 Oct 2013

Agreed — regardless of what the UK does per se, the chances of avoiding more than 2 degrees are 'slim.'

However, what the UK Met Office's (UKMO) UK Climate Act (UKCA) set out is carbon budget arithmetic for the next 100 years that (they say) gives 44 percent odds for keeping warming to 2 degrees.

If you then compare this with what came out with IPCC AR5 (where UKMO was a major player) you can see how the 'results' in AR5 compare with UKCA here: http://www.gci.org.uk/Documents/IPCC_AR5_3_FUTURES.pdf

In a nutshell, the UK Climate Act (UKCA) is either:
[a] twice too big, or
[b] a third too big, or
[c] exactly right. (!)

Makes you think, maybe?
Posted by Aubrey Meyer on 09 Oct 2013

The IPCC in some form should continue in the coming years. Who else will compile the 9000 papers with input from 1000 experts into only 3000 pages? Kevin Trenberth, David Keith and others who wish to work through other forums should be encouraged to do so. The IPCC can figure out how to resolve concerns about transparency, bureaucracy and size. And the world can benefit from the valuable interim work, whether it be a David Keith/Clive Hamilton geoengineering debate as was held recently at Harvard, methane releases, and data runs from data four or five years stale. But let's be clear: If the scientific community does not have an opportunity to seek consensus, China, Brazil, the present US Congress, Saudia Arabia, and Russia will be delighted to serve as proxies. I would prefer to see science left to the scientists, notwithstanding a 5 a.m. bedtime and a raucous peanut gallery.
Posted by Philip Boxell on 04 Nov 2013


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Fred Pearce, a Yale Environment 360 contributing writer, was in Stockholm last week for the release of the new U.N. climate report. A journalist based in the UK, he serves as environmental consultant for New Scientist magazine and is the author of numerous books. In previous e360 articles, Pearce has explored the question of whether environmentalists are increasingly taking anti-science positions and examined the role of invasive species on Ascension Island.



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