In the previous post, we discussed the origin of the 2 deg C threshold for dangerous impacts of climate change.
An example is happening at Copenhagen. The Association of Small Island States (AOSIS) and the Caribbean nations are lobbying for establishing a warming limit of 1.5 C rather than 2C. The real-world value of setting a temperature threshold notwithstanding, the AOSIS position demonstrates that the acceptable limit of warming is a value judgment based on scientific results rather than an immutable law of nature.
Why 1.5 degrees C, rather than 2C? The argument is based on the effect that sea level rise (and storm surge height) and coral reef degradation from bleaching and acidification would have on the economy and society.
Wednesday, December 16, 2009
In the previous post, we discussed the origin of the 2 deg C threshold for dangerous impacts of climate change.
Posted by Simon Donner at 10:36 AM
Monday, December 14, 2009
Media coverage of climate change often gives the impression the world’s scientific community all met and firmly established that the warming beyond +2 degrees C is dangerous to the future of society.
The planet does not have one clear "dangerous" temperature threshold. Two things needs to be explained clearly. First, the definition of dangerous climate change or unacceptable climate change is a normative choice. That choice could be based on analyses of scientific results but it is not a direct outcome of the science. Second, even if society could agree on one definition of "dangerous", climate science could not possibly produce one exact temperature threshold (e.g. 2 deg C), rather a frequency distribution of possible values. Besides, if climate science could produce an exact number, it would be an amazing coincidence that the number turned out to be an integer.
The precise evolution of 2 degC towards its exalted status in the media is a bit of a mystery to me – I’m sure some of the readers have followed these developments in more detail, and their comments on the subject are welcome. It more or less began with efforts by scientists to define climate change impacts that could be construed as dangerous under the UN Framework Convention on Climate Change. The common list of "dangerous" is the loss of major ice sheets, slowing of the thermohaline circulation, drops in food production, triggering a positive feedback like the release of methane from clathrates in ocean sediments, or loss of a major ecosystem like coral reefs.
Researchers tend to focus on physical and seemingly non-linear impacts like ice sheet melt rather than biological and gradual impacts like drops in food production or drops in biodiversity. True, there’s no ethical or scientific reason we should value sea level more than biodiversity or food production. In terms of policy, however, it is a more useful metric because we’re more likely to agree on whether losing the Greenland ice sheet is dangerous than what percent change in crop yields or biodiversity is dangerous. As well, future food production is fraught with technological, demographic and ethical uncertainties – although one could certainly argue the same is true for sea level.
Science can provide guidance for decision makers by projecting the impacts of different levels of warming, albeit with error bars. Beyond 2 deg C, paleo-climate results suggest possible long-term melting of the Greenland and /or West Antarctic Ice Sheets; studies have also pointed to the potential methane feedbacks and the degradation of the world’s coral reefs occurring at around 2 C.
But science alone cannot declare the "right" policy decision. Even such seemingly black-and-white definitions of dangerous like the loss of coral reefs or major ice sheets involve a normative judgment. Much of the world, for example, may decide that the productivity of coral reefs is acceptable collateral damage – it’s certainly possible that we’ve already inadvertently chosen that path. Although my colleagues and I who study the value of coral reefs to tropical cultures are likely to seriously disagree with such a decision to allow harmful impacts to reefs, we recognize (at least I do) that there is no immutable right or wrong policy decision that can emerge purely from our scientific results. Policy decisions need to consider real-world trade-offs that are often ignored by scientific analysis.
In sum, the oft-cited line that 2 degrees C is “what scientists conclude the world needs to avoid” is inaccurate. For one, the scientists disagree (Part II, coming soon). Moreover, though many of us may wish otherwise, the threshold can and should not emerge solely from science.
Posted by Simon Donner at 8:25 PM
Sunday, December 13, 2009
This post from five months ago seems more apropos at this time:
While I was doing field work in Kiribati a few weeks ago, I started reading Voltaire’s Bastards, the 1992 polemic by Canadian philosopher John Ralston Saul about the failure of reason in western society. You know, some light reading for the beach.
Saul steps back from the sniping between right and left to ask whether our deference to reason and structure has created an unthinking, technocratic society. It’s amazing this book was written before the internet transformed communications and before politics became a marketing exercise. This quote, speaking about how things of changed since the time of John Locke, could be talking about the inanity of the online debates between climate skeptics:
Facts at that time were such rare nuggets that no one realized how they would multiply. Everyone believed them to be solid and inanimate – to be true fact. No one yet understood that life would become an uncomfortable, endless walk down a seashore laid thick with facts of all sizes and shapes. Boulders, pebbles, shards, perfect ovals. No one had begun to imagine that these facts were without any order, impose or natural – that facts were as meaningful as raw vocabulary without grammar or sentences. A man could pick up any fact he wished and fling it into the sea and make it skip. A practiced, talented arm could make it skip three, perhaps four times, while a lesser limb might make a single plunk with the same concrete proof of some truth or other. Another man might build with these facts some sort of fortress on the shore.
As for Locke, he certainly did not think that facts would rapidly become the weapons, not only of good men but of evil mean, not only of truth but of lies.
Gavin Schmidt over at Real Climate has a terrific post about the repetitive spiral of blogging. In his case, the subject is debunking the climate skeptics. The basic conceit could apply to blogging as a whole. The popular politic blogs suffer from a more severe case of this affliction, rehashing the same issues over and over again, creating an urgency that often does not exist in reality.
Thanks to technology, anyone armed with either a few good sound-bites or an important sounding title can become an expert these days (link to IPCC “expert reviewer”). We end up with these shouting matches, on air and online, with both sides throwing out numbers and figures without any real context. The good lines, sound-bite or video clip enter the echo-chamber and get repeated, cited or linked over and over again. And voila, the steadily increasing ratio of commentary to original research and reporting.
This craziness is why we should appreciate institutions like the IPCC. With this all war of context-free facts, figures and soundbites being fought 24 hours a day, 365.25 days a year, sound summaries of the actual original research are more necessary than ever.
Wednesday, December 09, 2009
A scientific finding is not necessarily correct just because it appears in the peer-reviewed literature. There are a number of reasons. For one, not all journals are created equal. Some have less stringent review process. Some are more willing to accept papers from outside the editorial board's field of expertise or mandate. It's also important to remember that our scientific knowledge develops over time through trial and error via experiments done in the field, in the lab and on computers. Any one paper, no matter the author, no matter the journal, is not the law on a subject.
The trajectory of the publications and accumulated knowledge on a subject is going to be a better measure of scientific knowledge than the existence of one contrary publication, much like the multi-decadal temperature trends is a better indicator of what's happening to the climate than one year's weather.
A news story, I won't bother to link to the story, cited this list of "450 peer-reviewed papers supported skepticism of man-made global warming".
There are a few publications in well-respected scientific journals on the list. The large majority of those do not actually question the role of human activity in climate, rather point to complexity of climate change or the policy options(e.g. Zeebe et al. 2009 in Nature Geoscience). A large number are published editorials that do not actually contain any science. Many are from Energy and the Environment, a journal which advertises for papers skeptical of climate change, or Climate Research, where editors resigned because of a breakdown in the peer review process. And there are also papers from "Irrigation and Drainage", "Bulletin of Canadian Petroleum Geology", "Latvian Journal of Physics and Technical Sciences", "New Concepts in Plate Tectonics", "Journal of American Physicians and Surgeons", "Iron and Steel Technology" and "The Electricity Journal".
The list is being used to claim that there is widespread disagreement among scientists disagree about climate change. It is actually evidence for the exact opposite. Even if you included all 450 papers as relevant, critical analyses of the evidence for human influence on the climate, they would represent a minute fraction of the papers published on climate change in the past thirty years. In that way, it is evidence that the accumulated knowledge has led in another direction.
There's also a more common sense way to think about this list. If there really was so much disagreement about climate change in the scientific community, would the people who compiled this list needed to have included the articles from "Iron and Steel Technology" and "Topics in Catalysis"?
Monday, December 07, 2009
Today the US EPA announced its intention to pursue regulations on carbon dioxide and other greenhouse gases. Don't overlook this development. The only thing that carbon-intensive industries and senators from carbon-intensive states hate more than the US climate bill would be the EPA regulating carbon dioxide.
Thursday, December 03, 2009
I've avoided writing about "climategate" because of the artificial nature of the "scandal".
There is certainly a need to reduce tribalism in the scientific community (not just climate science!), improve peer review and improve the assessment process - I'll cheer those initiatives with enthusiasm.
That's not why the hackers released those emails were released online. The timing of the online publication of those e-mails were no fluke. The goal was to create a grand diversion from the important policy issues of the day. From the Times of London:
The computer was hacked repeatedly, the source close to the investigation said: “It was hacked into in October and possibly earlier. Then they gained access again in mid-November.” By not releasing the e-mails until two weeks before Copenhagen, the hacker ensured that the debate about them would rage during the summit. Very few of the e-mails are recent. One, in which Professor Jones mentions a “trick” which could “hide the decline” in temperatures, was sent in 1999.
Bob Ward, director of policy at the Grantham Research Institute on Climate Change, based at the London School of Economics, said: “From the timing of the release of the e-mails, it seems that the intention was not just to inform the public but to undermine mainstream climate researchers and influence the process in Copenhagen.”
Many scientists are now offering eloquent public explanations for the problems with some scientific practice and the assessment process. Terrific, but only in the abstract.
The problem is the impression given by a public blood letting. Climate scientists, people who trained in the physics and chemistry of the atmosphere, realize that regardless of issues with how some scientists conduct and publicize their work, all the basic concepts are still solid. That's not true for everyone else. So by constantly questioning scientific practice in public forums, it gives people the mistaken impressions there is dissension about the basic concepts, no matter how many caveats are then offered about strength of our understanding of the basic concepts (caveats just make it look like you're dodging the truth!). Good intentions aside, it is fueling public misconceptions about science and feeding the 24-7 scandal machine.
Perhaps the hackers understand climate dynamics better than we assume; they sure knew how to initiate a positive feedback.
Wednesday, December 02, 2009
Basically, the hydro-based and manufacturing-based provinces (the east and BC) are willing to be aggressive in reducing emissions and the more resource-intensive provinces are either reticent (Saskatchewan) or downright hostile (Alberta).
The objective of this post is not to dump on Alberta or the oil industry, rather to point out just how large the disagreement is within Canada. The huge disparity between the Alberta policy and that of all the other provinces does raise the question about what it is realistic for Canada. If, say, Alberta refuses to budge on its oil expansion and emissions plan, could neighbouring BC even come close to its reduction target? Keep in mind, a substantial quantity of the planned oil extraction may end up being piped across and refined in BC in order to be shipped to Asia.