Sea Level Rise Consensus Statement and Next Steps
April 1st, 2007Posted by: Roger Pielke, Jr.
In a paper by Jim Hansen that we discussed last week, he called for a consensus statement to be issued on global warming, West Antarctica and sea level rise, from relevant scientific experts. A group of scientists have beat him to the punch issuing a consensus statement last week:
Polar ice experts from Europe and the United States, meeting to pursue greater scientific consensus over the fate of the world’s largest fresh water reservoir, the West Antarctic Ice Sheet, conclude their three-day meeting at The University of Texas at Austin’s Jackson School of Geosciences with the following statement:
Read the whole thing, but the take home point is that there remain substantial uncertainties, as indicated in the following parts of the consensus statement:
*Satellite observations show that both the grounded ice sheet and the floating ice shelves of the Amundsen Sea Embayment have thinned over the last decades.
*Ongoing thinning in the grounded ice sheet is already contributing to sea-level rise.
*The thinning of the ice has occurred because melting beneath the ice shelves has increased, reducing the friction holding back the grounded ice sheet and causing faster flow.
*Oceanic changes have caused the increased ice-shelf melting. The observed average warming of the global ocean has not yet notably affected the waters reaching the base of the ice shelves. However, recent changes in winds around Antarctica caused by human influence and/or natural variability may be changing ocean currents, moving warmer waters under the ice shelves.
*Our understanding of ice-sheet flow suggests the possibility that too much melting beneath ice shelves will lead to “runaway” thinning of the grounded ice sheet. Current understanding is too limited to know whether, when, or how rapidly this might happen, but discussions at the meeting included the possibility of several feet of sea-level rise over a few centuries from changes in this region.
What is the policy significance of this statement?
1. Decisions about climate change will have to be made is the face of considerable uncertainties as those related to sea level rise will not be reduced anytime soon.
2. There is the “possibility of several feet of sea-level rise over a few centuries from changes in this region.” This contrasts strongly with Jim Hansen’s assertion that
“Spatial and temporal fluctuations are normal, short-term
expectations for Greenland glaciers are different from long-term expectations for West Antarctica. Integration via the gravity satellite measurements puts individual glacier fluctuations in proper
perspective. The broader picture gives strong indication that ice sheets will, and are already beginning to, respond in a nonlinear fashion to global warming.There is enough information now, in my opinion, to make it a near certainty that IPCC BAU climate forcing scenarios would lead to disastrous multi-meter sea level rise on the century time scale” (PDF).
Who will eventually be proven correct? I have no idea. Nor do I think that it matters at all from the perspective of policy (compare Naomi Oreskes’ views on this subject here) . The significance of this difference in views has more to do with issue of scientific advice than sea level rise itself — if scientists create an expectation that our decision making should be guided by consensus views of relevant experts, then they should take care when abandoning that approach to scientific advice when less politically convenient.
3. Bottom line: Sea level rose about 20 cm over the past century. The IPCC expects that it may rise from less than that amount to about 60 cm over the next century. RealClimate says they see another 40 cm possible in the IPCC report. And there is a long thin probability tail of higher amounts with low probability and high consequences.
So, What are the Next Steps?
**Mitigation actions can have only a small effect on sea level rise in the short term (e.g., from no impact decades hences to small impacts a century out) and thus respond primarily to the longer term threats of sea level rise more than a century in the future.
**The most (and only) effective responses to sea level rise over the century timescale will be adaptive. So once again we see that mitigation and adaptation respond to fundamentally different aspects of the climate issue. Mitigation and adaptation should occur in parallel.
**Mitigation and adaptation policies to in response to sea level rise have been looked at (notably in the work of Richard Tol, e.g., here), but far more needs to be done (e.g., as argued here in PDF and here in PDF). Sea level rise has, like so many aspects of the climate issue, fallen into the trap of the “prediction game” at the expense of research on the possible consequences of alternative policies in response to that which we already know. The sea level rise issue risks becoming simply a “poster child” for mitigation rather than an issue deserving more attention itself.
So my recommendation is: Rather than arguing over which predictions of the climate future (or which scientists) are correct, we know enough about the general trend in sea level rise and the possibility of a large increase to begin thinking and talking in far more depth about a wide range of possible policy responses, especially adaptation. Such discussions have to go beyond the simplistic use of future sea level rise as a argument to mitigate. Under any scenario of mitigation the adaptation challenge remains essentially the same, and similarly under any adaptation efforts the mitigation challenge does not change. Absolutely no science on the prediction of future sea level rise will alter this basic reality.
April 2nd, 2007 at 10:25 am
In fact Roger, all you are advocating is a continuation of existing human practises to sea level rises and other ocean related threats to human population centres.
A good example of a non-contentious adaptation project is the Thames Barrier in the UK. Its economic value to London is obvious and hence was a rational and supported policy decision.
However, the UK government has also made some economic decisions which are non-adaptation in nature. The most obvious example being the decision to scale back the funding given to protecting the East coast from sea erosion. Given that East Anglia includes considerable reclaimed land from the sea, increased erosion speeds have occurred at the displeasure of the local population.
The problem I see with your recommendation is that it requires a genuinely serious discussion of social, economic, political and environmental factors which I am very pessimistic about ever seeing from our politicians on both sides of the pond. Instead, the example of New Orleans shows that there remains a level of immaturity about both the politicians and environmental campaigners towards responding to a natural event who consequences were enlarged by a series of human decision making.
If we can ever get past the appealing to authority which is endemic in the current climate debate then perhaps instead of wasting time and effort on meaningless gestures, we can actually focus on the costs and benefits of adaptation policies.
April 2nd, 2007 at 5:08 pm
The Oreskes paper was excellent. Proofs, smoking guns, etc. do not exist in science. Yet I see that she agrees with you on using scientific consensus as the basis for political action. I disagree with both of you because I feel that the preponderence of evidence should be the true basis and that this is different from consensus. Consensus and the preponderance of evidence may be the same sometimes but not always.
Take the Weggener story as an example. The preponderence of evidence was multi-disciplinary and supported his claim that the continents were once joined. The only thing supporting the then consensus was present location and the theoretical objection that continents cannot move around. There was no policy needing input from that consensus/paradigm at the time, thank heavens, because those guys were not only wrong they were totally intolerant of Weggenerite opinion. Yet, their erroneus consensus held sway for decades.
Then take the Rachel Carson case. One year after her book, the Presidential Scientific Advisory Committee concluded that there was sufficient evidence to conclude that pesticides were harming the environment. Even though no consensus had yet formed in that brief time, they got the mitigation ball rolling based on the evidence they had on hand
When you rely on the preponderence of evidence you are open to change with future science. When you rely on consensus, you rely on sociological forces. Consensus can also become a cult and then there is a real problem.
The current consensus/cult on GW fights an opposition of “deniers”even though I cannot find anyone who denies that the earth is in a warming trend and that humans affect the climate. However, how you link these is a a matter of opinion and that means uncertainty and humility. To make progress in adaptation and mitigation is going to require action followed by evaluation followed by action in a continuous long term project. To be effective the process will need the input of all perspectives. Minds open to new evidence instead of pushing some theory will work best. It means thinking for oneself instead of following the crowd.
April 2nd, 2007 at 5:42 pm
Are these folks anywhere near where you work?
http://cires.colorado.edu/science/groups/steffen/greenland/melt2005/melt2005and1992.5inch.jpg
April 2nd, 2007 at 5:50 pm
Hank- Very very close … this guy is also
http://sciencepolicy.colorado.edu/admin/announcement_info.html?header=&footer=&event_id=1500
April 3rd, 2007 at 2:04 pm
Paul,
The problem I see with your preference for “preponderance of the evidence” is that deciding what constitutes preponderance takes a community of people, with all the messy sociology that entails: Who decides which data are reliable enough to use in framing policy and which are not? Who decides how much weight to put on different kinds of data?
Richard Lindzen clearly thinks the preponderance of the evidence is that anthropogenic warming constitutes only a small perturbation on natural climate cycles. Why is his definition of preponderance wrong and yours or mine correct? Similarly with tectonics, as late as 1970 many geologists thought the preponderance of the evidence said that the sea floor wasn’t spreading and that the continents’ locations were static. So in your scheme, who gets to decide where the preponderance of evidence points?
Thus, going for preponderance of evidence rather than consensus doesn’t get us anywhere when it comes to bringing science into public policy. The sociological considerations are inevitable and that’s a good thing because scientists exhibit unusually positive attitudes toward governing their community and the social cohesion we see in science is part of what makes it so reliable and productive. Sure there are missteps, but they are so exceptional that their very rarity argues in favor of science’s continued reliance on consensus both for purely scientific and also for policy-relevant questions.
—
PS, I wouldn’t overgeneralize about smoking guns. They do exist. It’s just that they are not ubiquitous and you can’t always find one when you want one (see A. Weinberg, Science and Trans-Science, Minerva 10, 484 (1972)).
The correlations amongst ozone, ClO, NOx, and OH in the antarctic stratosphere as measured both by balloon and more dramatically by aircraft, formed a clear smoking gun that anthropogenic chlorine was causing an ozone hole via the mechanisms proposed by Solomon. For policy purposes, this came late in the game and the Vienna treaty was already in place, but this undeniable evidence was very significant for adopting accelerated mitigation schedules in the London and Copenhagen rounds (see, e.g., R. Benedick, Ozone Diplomacy (Harvard, 1998), Ch. 9-11).
But two things are clear: There is no analogous smoking gun for sea-level rise. And even with ozone, it would not have been useful to wait for the smoking gun to begin negotiating the Vienna convention.
April 3rd, 2007 at 4:02 pm
Jonathon,
Your points are well taken. However, my focus is more on the individual in the process rather than on the structure or process itself.
I agree that “a community of people” deciding what is the preponderance of evidence is messy sociology and to build this requirement into a decision making structure will probably result in an unintended authoritarian structure. Indeed consenus particularly when it morphs into the paradigm can do just that in addition to the good that you point out.
My point is that I think the scientific community should not strive for consensus nor should the non-scientific community expect scientific consensus.
The political world where the decision-makers reside is a different matter. There consensus must be sought or at least a majority should be settled on for action to be taken. Each decision-maker should evaluate the evidence on his own and then mix it with poliical considerations to arrive at a decision. I know that the immense diversity of issues makes this tough but that is why those enormous staffs exist. I am also aware of the varied quality of decision makers but that problem is perrenial.
In short I believe that the independence of the Lindzens and Hansens should be respected as representative of science rather than some consensus. Politicians can use such independence as a personal model when they enter into the sausage making process in search of that consenus,
P.S. Your use of the smoking gun metaphior is probably better than mine. I was likening it to 100% certainty which we know is impossible.
April 4th, 2007 at 2:27 pm
Speaking of reticence, I suppose this qualifies as agency-wide imposition thereof.
http://www.realclimate.org/index.php/archives/2007/04/the-sheep-albedo-feedbacki/#comment-30194
April 9th, 2007 at 7:19 am
Roger:
I agree with you that “we know enough about the general trend in sea level rise and the possibility of a large increase to begin thinking and talking in far more depth about a wide range of possible policy responses, especially adaptation. Such discussions have to go beyond the simplistic use of future sea level rise as a argument to mitigate.”
However, I think you gloss over key differences in the decision-making processes relating to mitigation and adaptation. While individuals, firms and communities in the developed economies will largely adapt on their own – and indeed already are – to the climate as it changes (based on their perceptions of likely changes and time horizons), mitigation requires large-scale national and international cooperation by which all nations share the costs of controlling carbon and other forcing factors.
Adaptation involves large-scale cooperation only to the extent the western economies are willing to provide material assistance to help developing nations – an effort that will may require intrusive involvement to help these countries develop suitable governance structures, so that aid money is not simply wasted.
Local adaptation will proceed largely without central government policy, but mitigation and adaptation approaches that involve coordination with the rest of the world naturally require poltical will across a number of nations. Such political will is more likely to be garnered if the peoples involved view the problem to be addressed as relatively immediate and severe – as opposed to something that is less pressing or can be deferred.
For this reason, one can readily understand how “the simplistic use of future sea level rise” is used to gather the political will to address mitigation and adaptation on national and international levels. I would note that even Richard Tol, in the first paper you cite, concludes “that the possibility of a anthropogenic-climate-change-induced WAIS collapse would strengthen the case for greenhouse gas emission reduction.”
April 9th, 2007 at 11:02 am
“While individuals, firms and communities in the developed economies will largely adapt on their own – and indeed already are – to the climate as it changes (based on their perceptions of likely changes and time horizons), mitigation requires large-scale national and international cooperation by which all nations share the costs of controlling carbon and other forcing factors.
Adaptation involves large-scale cooperation only to the extent the western economies are willing to provide material assistance to help developing nations – an effort that will may require intrusive involvement to help these countries develop suitable governance structures, so that aid money is not simply wasted.”
I don’t agree. There are *plenty* of adaptation measures that could involve multinational co-operation, and that would not involve intrusive interference with other governments.
1) A cyclonic storm (i.e. hurricane, typhoon) storm surge protection system would be of great use to the U.S., but also to the Netherlands, Japan, the Philippines, Bangladesh, Indonesia, and other countries with exposed coasts.
The U.S. could either develop such a system itself, or in cooperation with other wealthy countries. Then the system could be given away to poor counties (e.g., Bangladesh) as a foreign aid measure. Because the system would be deployed at the ocean shoreline, there would be no need to become intimately involved with the countries to whom the system is given.
2) Polar bear aid: The U.S. and Canada (and potentially Russia) could develop systems of artificial (or insulated) ice flows such that polar bears would have landing places, even if the north polar ice is completely lost in
3) All the countries of the world could get together to obtain and maintain DNA banks and/or captive protection programs for tropical mountain species that could be theoretically driven to extinction by global warming. With sufficient DNA banks, it is possible (or even likely) that the animals and plants in question could be cloned (as cloning technology improves) even if they do go extinct.
4) All the countries who could be hurt by rising sea levels could get together to research how to slow or even reverse melting in Greenland and the Antarctic…or to capture the meltwater for delivery to arid areas of the world where the water would not drain into the ocean after use (e.g., places where the spent water would go to underground aquifers rather than the ocean).
5) And there are obviously the “tropical” diseases like malaria, dengue, and others (even including diarrhea) for which multinational cooperation would be worthwhile.
6) Use of electrolysis to help build coral reefs, or localized cold water injection to prevent bleaching.
This is only an extremely partial list, developed with very little thought. A great many more adaptation measures could probably be identified; these adaptation measures would yield far more immediate and larger benefits than reducing CO2 emissions.
April 9th, 2007 at 9:30 pm
Mark, thanks for the comments.
I do agree with you that there are many opportunities for international cooperation on adaptation that will not necessarily involve improving the governance of third world nations, as you point out. However, as action on them involves the same issues of global/regional public goods, cost-sharing and free riding that affect mitigation, political will and a shared purpose and commitment across a number of nations will be needed – political will that will develop when the problem to be addressed is seen as sufficiently pressing and the proposed measures sufficiently efficacious.
Addressing the problems of governance inside developing nations will be even stickier than the measures that the developed economies can take unilaterally – including international mitigation measures that involve only the most significant developing economies.
I agree that international adaptation measures such as you propose would yield “far more immediate and larger benefits than reducing CO2 emissions” but, because of the nature of our international prisoners’ dilemma, most such measures will not occur until agreements to start pricing our positive forcings are also in place.