Science – Page 51 – a sibilant intake of breath

Climate Change Futures Markets

Over at FiveThirtyEight – a website that leapt to fame on the basis of statistical analysis of the 2008 US election – there is a discussion of futures markets for climate change. The idea is to let people place bets on what will happen, and the hope is that the sum of opinions backed up with money will provide reasonably high quality information on what is likely and what is not:

Personally, I’d envision a robust series of contracts on temperature, CO2 emissions, precipitation, and perhaps tropical storms that expired at various intervals along the lines of those used for US Treasury bonds — say at 3, 5, 7, 10, 20, and 30 years. I’d encourage the use of options and perhaps derivatives, which can be helpful in pricing not just the mean estimates of temperature or precipitation but also the uncertainty surrounding these estimates. I’d run the markets through a major, cross-national platform such as the United Nations, IMF or World Bank, so as to encourage participation and create liquidity. And I’d make them open to as many people as possible with few legal restrictions or transaction costs.

This is similar to the idea of using such markets to predict the outcome of elections. While implementing the idea is bound to produce some problems, it could be a good thing to try. For one thing, it could help create mechanisms through which additional insurance could be provided for climatic risks, whether of extreme weather, crop failure, or other phenomena.

The Copenhagen Diagnosis

More than three years have passed since the Fourth Assessment Report (AR4) of the Intergovernmental Panel on Climate Change (IPCC). Given that the AR5 isn’t due until 2014, it is perhaps appropriate that a group of scientists have released a more current summary of peer-reviewed scientific work on climate change, in the lead-up to the climate negotiations in Copenhagen next month.

The Copenhagen Diagnosis is intended as an interim evaluation. It was written by scientists from Germany, the US, Australia, Austria, Switzerland, the UK, and Canada (with the University of Victoria’s Andrew Weaver participating). Written by a comparatively small group of people, it doesn’t have the same level of authority as an IPCC report. Nonetheless, it seems appropriate that it be taken into consideration as states are considering what ought to be done about climate change. On methodology, the prefare to the report specifies that:

The science contained in the report is based on the most credible and significant peer-reviewed literature available at the time of publication. The authors primarily comprise previous IPCC lead authors familiar with the rigor and completeness required for a scientific assessment of this nature.

The report was published by the The University of New South Wales Climate Change Research Centre (CCRC) in Sydney.

Some of the key conclusions of the report include:

Global carbon dioxide emissions from fossil fuels in 2008 were nearly 40% higher than those in 1990. Even if global emission rates are stabilized at present-day levels, just 20 more years of emissions would give a 25% probability that warming exceeds 2°C.
Over the past 25 years temperatures have increased at a rate of 0.190C per decade, in every good agreement with predictions based on greenhouse gas increases. Even over the past ten years, despite a decrease in solar forcing, the trend continues to be one of warming. Natural, short- term fluctuations are occurring as usual but there have been no significant changes in the underlying warming trend.
A wide array of satellite and ice measurements now demonstrate beyond doubt that both the Greenland and Antarctic ice-sheets are losing mass at an increasing rate. Melting of glaciers and ice-caps in other parts of the world has also accelerated since 1990.
Summer-time melting of Arctic sea-ice has accelerated far beyond the expectations of climate models. This area of sea-ice melt during 2007-2009 was about 40% greater than the average prediction from IPCC AR4 climate models.
Satellites show great global average sea-level rise (3.4 mm/yr over the past 15 years) to be 80% above past IPCC predictions. This acceleration in sea-level rise is consistent with a doubling in contribution from melting of glaciers, ice caps and the Greenland and West-Antarctic ice-sheets.
By 2100, global sea-level is likely to rise at least twice as much as projected by Working Group 1 of the IPCC AR4, for unmitigated emissions it may well exceed 1 meter. The upper limit has been estimated as – 2 meters sea-level rise by 2100. Sea-level will continue to rise for centuries after global temperature have been stabilized and several meters of sea level rise must be expected over the next few centuries.
Several vulnerable elements in the climate system (e.g. continental ice-sheets. Amazon rainforest, West African monsoon and others) could be pushed towards abrupt or irreversible change if warming continues in a business-as-usual way throughout this century. The risk of transgressing critical thresholds (“tipping points”) increase strongly with ongoing climate change. Thus waiting for higher levels of scientific certainty could mean that some tipping points will be crossed before they are recognized.
If global warming is to be limited to a maximum of 2°C above pre-industrial values, global emissions need to peak between 2015 and 2020 and then decline rapidly. To stabilize climate, a decarbonized global society – with near-zero emissions of CO2 and other long-lived greenhouse gases – need to be reached well within this century. More specifically, the average annual per-capita emissions will have to shrink to well under 1 metric ton CO2 by 2050. This is 80-90% below the per-capita emissions in developed nations in 2000. (Emphasis mine)

In short, there are many good reasons to worry about the state of the climate system, as well as what will happen within it if humanity doesn’t begin effectively reducing our emissions. Hopefully, those messages will not be lost on the people negotiating in Copenhagen, even if the prospects for a comprehensive agreement are not looking terribly good right now.

Both the full report and an executive summary are available online in a number of languages.

Asymmetric behaviours in climate debates

James Hoggan’s Climate Cover-Up: The Crusade to Deny Global Warming neatly expresses a key assymmetry that arises in debates between those supporting and those questioning the consensus view that climate change is primarily being cause by human greenhouse gas emissions:

When it comes to staking out positions and shifting the middle ground, industry-funded strategists seem to have seized and kept the strategic initiative. Any time anyone on the science side makes even the smallest overstatement, they immediately face the full resources of a think tank echo chamber attack. And because conscientious scientists are so quick to recognize and acknowledge when something is not exactly correct, the attackers have won many apologies, corrections, or reinterpretations, which they have used to argue that all of climate science is frail and uncertain.

At the same time, the more exuberant deniers have often said things that were flat-out wrong, and then have refused to acknowledge or apologize for their misrepresentations. In response the environmental community – lacking both the resources and sense of common purpose more typical of the antiscience crowd – has been ineffective in launching countercriticism. (p. 130 paperback)

This is certainly something we have seen in discussions here. Deniers like Dan Pangburn trot out arguments that have been factually or logically rebutted over and over, while hammering at minor components of arguments being made by others. When people dutifully rebut them again, it may provide the false sense that a meaningful debate is still ongoing.

Of course, there are plenty of other circumstances in which we legitimately hold one side of a conflict to higher standards. Scientists should not stoop to the level of denying their mistakes. That said, it does seem appropriate to draw attention to this asymmetry as evidence of how one side of this debate is fighting dirty.

Climate denial and conservative think tanks

In 2008, three academics published the paper “The Organization of Denial: Conservative Think Tanks and Environmental Scepticism” in the journal Environmental Politics. The researchers analyzed 141 books published between 1972 and 2005, all of which expressed skepticism about the seriousness of environmental problems, including climate change, stratospheric ozone depletion, biodiversity loss, resource shortages, air pollution, and others. Of these, the researchers found that over 92% were published by conservative think tanks, written by authors affiliated with those think tanks, or both.

Contrast that with Naomi Oreskes’ 2004 Science article: “Beyond the Ivory Tower: The Scientific Consensus on Climate Change,” in which she examined the positions taken on climate change within peer-reviewed scientific articles. Of the 928 articles examined, none expressed disagreement with the consensus view that humanity’s greenhouse gas emissions are causing climate change.

Peter Jacques uses their survey to argue that “scepticism is a tactic of an elite-driven counter-movement designed to combat environmentalism.” That is to say, groups with an economic or ideological commitment to the present arrangement – where most energy comes from fossil fuels and the atmosphere is a free dumping ground for greenhouse gasses – are continuing to press for policy inaction by self-serving means, using information and arguments at odds with that in the peer-reviewed scientific literature. None of that is surprising, though it does demonstrate the irony of climate change deniers claiming to be an embattled and persecuted minority, concerned only with getting the truth out despite the efforts of nefarious scientists and environmentalists to silence them.

The Climatic Research Unit’s leaked emails

160 megabytes worth of emails – ostensibly from the University of East Anglia’s Climatic Research Unit – have apparently been obtained by hackers and posted online. Being emails between colleagues, they are written in a less formal style than public documents. Some blogs and news sources critical of the mainstream scientific view are hailing the emails as proof of poor practice within the scientific community, or evidence that the consensus view on climate change is incorrect or an intentional fabrication. Various climate change blogs have put up responses to the whole event and to those allegations:

Grist: Skeptics claim global warming is fake after top scientists’ emails hacked at CRU
RealClimate: The CRU hack
Greenfyre’s: CRU Hack, time to hit back … hard
DeSmogBlog: Climate contrarians spinning hard with stolen email files

Firstly, it isn’t clear that these emails contain evidence of any wrongdoing. Secondly, it hasn’t been established whether the documents are all genuine and unaltered. Thirdly, and most importantly, the consensus on anthropogenic climate change is bigger than any one specific institution. It is based on multiple lines of evidence that support the same conclusions – something that cannot be said about alternative hypotheses, such as that nothing is happening or that observed warming is not mostly being caused by greenhouse gasses.

RealClimate probably has the best analysis on the significance of all this:

More interesting is what is not contained in the emails. There is no evidence of any worldwide conspiracy, no mention of George Soros nefariously funding climate research, no grand plan to ‘get rid of the MWP’, no admission that global warming is a hoax, no evidence of the falsifying of data, and no ‘marching orders’ from our socialist/communist/vegetarian overlords. The truly paranoid will put this down to the hackers also being in on the plot though.

Instead, there is a peek into how scientists actually interact and the conflicts show that the community is a far cry from the monolith that is sometimes imagined. People working constructively to improve joint publications; scientists who are friendly and agree on many of the big picture issues, disagreeing at times about details and engaging in ‘robust’ discussions; Scientists expressing frustration at the misrepresentation of their work in politicized arenas and complaining when media reports get it wrong; Scientists resenting the time they have to take out of their research to deal with over-hyped nonsense. None of this should be shocking.

It’s obvious that the noise-generating components of the blogosphere will generate a lot of noise about this. but it’s important to remember that science doesn’t work because people are polite at all times. Gravity isn’t a useful theory because Newton was a nice person. QED isn’t powerful because Feynman was respectful of other people around him. Science works because different groups go about trying to find the best approximations of the truth, and are generally very competitive about that. That the same scientists can still all agree on the wording of an IPCC chapter for instance is thus even more remarkable.

That said, you can be sure that climate change delayers and deniers will be milking these emails for years – using them to continue to cast doubt on the strength of the scientific consensus about climate change. Thankfully, it does seem as though the world’s political elites are increasingly aware of the strength of the scientific consensus and the incoherence of the views of those who deny it.

[Update: 3 December 2009] Nature has posted an editorial about this whole incident. It makes reference to two open archives of online climate data – maintained by the IPCC (http://www.ipcc-data.org) and the US National Climatic Data Center (http://www.ncdc.noaa.gov/oa/ncdc.html).

[Update: 14 December 2009] Newsweek has printed a comprehensive evaluation of the significance of the CRU emails, written by Jess Henig of FactCheck.org. It concludes that the emails sometimes “show a few scientists in a bad light, being rude or dismissive” but that the emails do not undermine the IPCC consensus, and that: “E-mails being cited as “smoking guns” have been misrepresented.”

[Update: 20 June 2010] Wrap-up video on the CRU emails

Open thread: climate change and growth

One of the biggest disagreements that exists among those who believe that action is required to mitigate anthropogenic climate change is between those who see it as a problem that can be managed within existing economic systems and those who argue that it requires profoundly different ones.

The first view can be encapsulated as ‘climate change as an engineering problem.’ We just need to give people the right incentives, and enact policies to change over the energy basis of society to one that is carbon-neutral. Readily available tools for doing this include Pigouvian taxes: those meant to incorporate the societal harms associated with various actions into the prices paid by those who do them. Examples include carbon taxes, road taxes, etc.

The second view is more like ‘climate change as a symptom of the problem of capitalism.’ Indian environmentalist Sunita Narain expresses it well:

All technofixes [for climate change] – biofuels, GM crops or nuclear power – will create the next generation of crisis, because they ignore the fundamental problems of capitalism as a system that ignores injustice and promotes inequality.

In this view, changes made within existing economic systems will never be able to go far enough to produce a sustainable society.

Deciding how to act, there are risks on both sides. The engineering approach will face less resistance, meaning it can be rolled out faster, with a higher probability of getting the key elements in place soon. It may not, however, have the power required to solve the problem. The radical approach may ultimately have more capacity to effect societal change, but it would almost certainly take longer, and there is a significant risk that the new society forged wouldn’t even achieve the objective of climate stability. Capitalism’s major ideological competitor – communism – certainly wasn’t environmentally benign, or effective at managing environmental issues.

Can we cut human emissions to zero, thus stabilizing climate, while retaining the basic elements of the present economic system? If so, what mechanisms are the most important to put in place. If not, what sort of system do we need? One that is more democratic, or more authoritarian? One that alters the relations between humans and the planet how?

Casting doubt on fusion power

Looking at a diagram of a proposed fusion reactor, it is easy to get the false sense that such technologies will provide clean and inexpensive power within a few decades: fusing tritium and deuterium to produce heat, while generating new fuel from lithium using the neutrons produced.

A post on The Oil Drum enumerates the many technical challenges associated with achieving that aim, going so far as to say that dreams about fusion power should be ‘ended’ as a consequence. Written by Dr. Michael Dittmar, a researcher with the Institute of Particle Physics of ETH Zurich, the article enumerates a number of significant problems:

Large amounts of tritium are required and various problems exist with it as a material and a fuel.
Materials from which reactor walls can be made are unavailable, and far beyond anything that is available.
Many obstacles exist to breeding tritium from Lithium-6.
Similarly, obstacles exist to extracting tritium from the lithium blanket and delivering it in a pure form into the chamber where fusion is occurring.
Reactors may not be able to breed enough tritium to keep themselves going, much less provide excess tritium for new facilities.

While this may not be cause for declaring fusion a complete non-starter, it is at least a useful way to temper the assumption that fusion power will emerge any decade now, providing a pain-free solution to the problems of climate change and fossil fuel depletion.

The article also lists problems with fission reactors that breed plutonium or use thorium as fuel: both options mooted in response to concerns about limited availability of uranium for use in conventional reactors. All this is a reminder that – while renewables may be costly and have intermittency problems to manage – there is every reason to believe they can be practically deployed starting immediately.

Anthropogenic climate change: evidence from isotopic ratios

Back in 2003, Prosenjit Ghosh and Willi Brand described one of the more clever ways in which the link between fossil fuel combustion and the accumulation of carbon dioxide in the atmosphere has been demonstrated. In their article “Stable isotope ratio mass spectrometry in global climate change research” (PDF), they discuss how the ratio of isotopes of carbon in the atmosphere can be used to identify the sources of atmospheric CO2. Their work was published in 2003, in the International Journal of Mass Spectrometry.

By tracking the ratio of carbon-12 to carbon-13 in the atmosphere, the distinctive imprint of fossil fuel combustion can be identified. This is really just confirmation of the inevitable chemical fact that burning coal, oil, and natural gas produces CO2. Nevertheless, it is nice to have an independent line of evidence showing that human activities really are the major cause behind observed increases in the atmospheric concentration of CO2.

The IPCC, climate, and consensus

In addition to sketching out the borders of reasonable debate on climate change, Mike Hulme has written some intelligent things on scientific consensus, as embodied in the Intergovernmental Panel on Climate Change (IPCC) reports:

[T]he use of consensus is merely one (structured) way of distilling evidence – evidence which might be somewhat ambiguous, incomplete or contradictory or where there is latitude for genuine differences of interpretation – into an overall agreed statement on an issue of scientific or public importance.

He also quotes an intelligent comment from a volume by P.N. Edwards and S.H. Schneider:

We have discussed earlier… why it may often be necessary for science to use consensus processes as a way of consolidating knowledge so that it can be useful for policy. Consensus knowledge, by construction, will always allow experts to disagree, with knowledgeable opinion existing at either tail of the distribution of views… Such scientific consensus is not ultimate ‘truth’ and, on occasion, may turn out to be wrong. But the alternatives to the IPCC style of consensus-building are even less likely to command widespread authority within the worlds of science and policy. ‘Vastly better [than random solicitation of views] is the work of groups like the IPCC… which although slow, deliberative, sometimes elitist and occasionally dominated by strong personalities, are nonetheless the best representation of the scientific community’s current general opinion.’

The big problem, from a policy perspective, is the number of politically influential agents who either continue to deny that potentially dangerous anthropogenic climate change is taking place, or who argue for various reasons that nothing ought to be done about it. The fact that these people don’t have views that are reconcilable with the best available evidence doesn’t mean they aren’t able to influence the public policy debate.

The boundaries of reasonable climate change debate

In his well-argued book Why We Disagree About Climate Change, Mike Hulme does a good job of establishing the boundaries of the legitimate debate about climate change and what we ought to do about it:

Many of the disagreements that we observe are not really disputes about the evidence upon which our scientific knowledge of climate change is founded. We don’t disagree about the physical theory of absorption of greenhouse gases demonstrated by John Tyndall, about the thermometer readings first collected from around the world by Guy Callendar, or about the possibility of non-linear instabilities in the oceans articulated by Wally Broecker. We disagree about science because we have different understandings of the relationship of scientific evidence to other things: to what we may regard as ultimate ‘truth,’ to the ways in which we relate uncertainty to risk, and to what people believe to be the legitimate role of knowledge in policy making.

That’s as good a concise summary as I’ve seen. If the people you are debating accept that temperatures are rising, that greenhouse gasses cause warming, and the the climate system may react to human emissions in deeply disagreeable ways, you are within the realm where reasonable discussions can occur. By contrast, if your partners in discussion assert that climate is not changing, greenhouse gasses have nothing to do with it, and that any change will surely be benevolent and gradual… well… here be dragons.