Thursday, December 27, 2007
There is no obvious reason why we can't do better, and yet the promised progress in this direction isn't appearing anywhere near as fast as the policy sector needs it.
Specifically, is it possible to provide useful regional prognostics of the consequences of global change? That's what most people want us to do and what most people think we are up to. Whether that is what we want to do or not, I think some of us should rise to the occasion.
I would like to make the case that I can help do something about this. It's a personal ambition to actually influence the architecture of a significant climate modeling effort before I retire. I think my skill set is unusual and strong in this regard, but unfortunately my track record is less so. It's not that I haven't accomplished anything as a coder, a software architect, a EE, or a manager, actually. It's just that academia treats my time in industry as tantamount to "unemployment" and vice versa.
At the least, though, I can try to start a conversation. Are we stuck? If so, why? What could be done with a radical rethinking of the approach?
I have an essay on one view of the problem on another blog of mine. ... I think both climate dynamics and software engineering issues are germane, and I'd welcome any informed discussion on it. There seem to be enough people from each camp lending me an ear occasionally that we might be able to make some progress.
Update: Well, since I've failed to move the discussion over there, I'll move the article here. Thanks for any feedback.
I believe that progress in climate modeling has been relatively limited since the first successes in linking atmosphere and ocean models without flux corrections. (That's about a decade now, long enough to start being cause for concern.) One idea is that tighter codesign of components such as atmosphere and ocean models in the first place would help, and there's something to be said for that, but I don't think that's the core issue.
I suggest that there is a deeper issue based on workflow presumptions. The relationship between the computer science community and the application science community is key. I suggest that the relationship is ill-understood and consequently the field is underproductive.
The relationship between the software development practitioners and the domain scientists is misconstrued by both sides, and both are limited by past experience. Success in such fields as weather modeling and tide prediction provide a context which inappropriately dominates thinking, planning and execution.
Operational codes are the wrong model because scientists do not modify operational codes. Commercial codes are also the wrong model because bankers, CFOs and COOs do not modify operational codes. The primary purpose of scientific codes as opposed to operational codes is to enable science, that is, free experimentation and testing of hypotheses.
Modifiability by non-expert programmers should be and sadly is not treated as a crucial design constraint. The application scientist is an expert on physics, perhaps on certain branches of mathematics such as statistics and dynamics, but is typically a journeyman programmer. In general the scientist does not find the abstractions of computer science intrinsically interesting and considers the program to be an expensive and balky laboratory tool.
Being presented with codes that are not designed for modification greatly limits scientific productivity. Some scientists have enormous energy for the task (or the assistance of relatively unambitious and unmarketable Fortran-ready assistants) and take on the task with energy and panache, but the sad fact is that they have little idea of what to do or how to do it. This is hardly their fault; they are modifying opaque and unwelcoming bodies of code. Under the daunting circumstances these modifications have the flavor of "one-offs", scripts intended to perform a single calculation, and treated as done more or less when the result "looks reasonable". The key abstractions of computer science and even its key goals are ignored, just as if you were writing a five-liner to, say, flatten a directory tree with some systematic renaming. "Hmm, looks right. OK, next issue."
This, while scientific coding has much to learn from the commercial sector, the key use case is rather atypical. The key is in providing an abstraction layer useful to the journeyman programmer, while providing all the verification, validation, replicability, version control and process management the user needs, whether the user knows it or not. As these services become discovered and understood, the value of these abstractions will be revealed, and the power of the entire enterprise will resume its forward progress.
It's my opinion that Python provides not only a platform for this strategy but also an example of it. When a novice Python programmer invokes "a = b + c", a surprisingly large number of things potentially happen. An arithmetic addition is commonly but not inevitably among the consequences and the intentions. The additional machinery is not in the way of the young novice counting apples but is available to the programmer extending the addition operator to support user defined classes.
Consider why Matlab is so widely preferred over the much more elegant and powerful Mathematica platform by application scientists. This is because the scientists are not interested in abstractions in their own right; they are interested in the systems they study. Software is seen as a tool to investigate the systems and not as a topic of intrinsic interest. Matlab is (arguably incorrectly) perceived as better than Mathematica because it exposes only abstractions that map naturally onto the application scientist's worldview.
Alas, the application scientist's worldview is largely (see Marshall McLuhan) formed by the tools with which the scientist is most familiar. The key to progress is the Pythonic way, which is to provide great abstraction power without having it get in the way. Scientists learn mathematical abstractions as necessary to understand the phenomena of interest. Computer science properly construed is a branch of mathematics (and not a branch of trade-school mechanics thankyouverymuch) and scientists will take to the more relevant of its abstractions as they become available and their utility becomes clear.
Maybe starting from a blank slate we can get moving again toward a system that can actually make useful regional climate prognoses. It is time we took on the serious task of determining the extent to which such a thing is possible. I also think the strategies I have hinted at here have broad applicability in other sciences.
I am trying to work through enough details of how to extend this Python mojo to scientific programming to make a credible proposal. I think I have enough to work with, but I'll have to treat the details as a trade secret for now. Meanwhile I would welcome comments.
Congressman Vern Ehlers, R-MI, and congressman Rush Holt, D-NJ, have agreed to co-chair the non-partisan initiative, called ScienceDebate2008.com, whose signers also include fourteen Nobel laureates, several university presidents, other congresspersons of both parties, the president of the Academy of Evangelical Scientists and Ethicists, and the heads of several of America's major science organizations, including the American Association for the Advancement of Science.
These congressmen are apparently "also scientists" whatever that might mean. Anyway it's great news!
More at Intersection and at the ScienceDebate site.
Wednesday, December 26, 2007
The management and enforcement of the protection regime in Indonesia is insufficient, and illegal activities - such as logging, hunting and mining, is rampant. The RAPPAM methodology, developed by WWF, has been used to assess the relative pressures and threats using questionnaires and workshops. Borneo and Sumatra are home to the Orangutan, and the protected areas represent vital habitat for the survival of the species.Does Indonesia's national sovereignty trump everything else? Does Indonesia have a right to sell off its national parks, much as Texas claims to have? Do orangutans have rights? Do I have a right to live in a world where orangutans are not extinct?
I don't know, but I think that small worlds are different from big ones. Eventually obligations trump rights; the smaller the world the more so.
Tuesday, December 25, 2007
Given the nature of the call, the following is probably not going to strengthen my argument, but I think it's interesting and I welcome your input. (I'd especially welcome commentary from JM and JM).
The difficulties in constructing working high-performance codes color the scientific process and other decision support networks dependent on it.
To some extent the problem in climate modeling is based on the origins of the component models in operational prediction communities (such as weather prediction), wherein the goal of software design is the cost-efficient optimal projection of the state of the atmosphere into the near future. It's often noted that this is an initial value problem while running similar codes in climate mode is a boundary condition problem; the objectives are substantially different. Nevertheless, a weather code has a climate and a climate code has weather; these are structurally similar. Accordingly, the methods of the weather modeling community are injected into climate methodologies.
The problem is not in the different mathematical structure of the purposes at hand. It is in the different social structures. A weather model is write-once, run many times. Its purpose is efficiency and correctness. A climate model is an experimental platform. While it is efficiency constrained, flexibility and transparency are key to its utility, keys which are of trivial importance in operational settings.
I believe that despite the very slow progress of the past decade or so, climate modeling has the potential to be vastly more skillful. It seems at least that this should be put to the test. Flexibility, transparency, interoperability, testability and accessibility to automated reasoning are needed. Climate modeling needs to partake of modern agile development methodologies such as those at Google and similar very high productivity companies. Certainly the potential value add is there. It's time that some institutional structure existed to support this.
Monday, December 24, 2007
Saturday, December 22, 2007
Friday, December 21, 2007
A lot of us live in intellectual silos, it seems. A sobering survey of more than 1,700 voters, published by the Pew Research Center for the Public and the Press in January, found that more education, for example, does not shift attitudes, and instead actually hardens them.The linked survey also has a number of other daunting statistics, but I think the one that Andrew Revkin focuses on is particularly suprising and unfortunate.
In the survey, Republicans with a college degree were substantially more skeptical about global warming than Republicans without one. Democrats with a college degree were significantly more convinced global warming was a problem than were Democrats who didn’t go to college.
This is bad news for anyone commenting on Dot Earth who plans to try to win over readers with starkly different attitudes. My hope is that the interactions here will be a little bit like the scientific process, whittling away at unsupported arguments, building on areas of agreement and creating a trajectory toward understanding and meaningful action.
Does anyone know of comparable data in other countries?
Update: I found comment #10 on the referenced Dot Earth article especially interesting among many interesting responses. Consider this advice:
So if you’re interested in bringing doubters/skeptics over to an understanding of the theory, be a little be humble, be as familiar with the limits of the theory as you are with the strengths, and try to resist making calls to ban SUVs, restrict reproductive rights, constrict the economy and other nutty ideas.So what am I to do? Of course the science stands by itself, and I am glad that occasionally someone can be won over by reason.
On the other hand, I think the taboo against considering the nature of the growth imperative is very much a core issue in coming up with a sensible solution to our problems. Even if a growth-imperative-friendly greenhouse gas strategy is meaningful, something else will break soon enough. I don't understand why this particular belief, that it is "nutty" to "constrict" the "economy", is immune from skeptical inquiry.
Update: My response to comment #10 is visible as comment #131
Update: Some excellent postings by Edwin Hall on the Dot Earth article. Please take special note of this one.
Thursday, December 20, 2007
Edward Greisch: See the chart on page 274 of “Six Degrees” by Mark Lynas. Mark Lynas says we have until 2015 to BEGIN REDUCING our total CO2 output and we have until 2050 to actually reduce our CO2 output by 90%. Mark Lynas says if we don’t follow the schedule in Six Degrees, we will encounter positive feedbacks which will take the control of the climate out of our hands. Civilization may fall anyway well before 2050, but we can avoid going extinct by 2100. Mark Lynas says we have to hold the CO2 level to 400 parts per million to have a 75% chance of avoiding the positive feedbacks. Is Mark Lynas correct? 8 years is a very tough timetable to stop the building of coal fired power plants and replace some coal fired power plants with nuclear. I doubt that anything else other than a plague that kills a few billion people could make a dent within 8 years.No matter what the circumstance, unless we are finally extinct, there is always a best we can do. We should strive in our imperfect way to stay close to that.
[Response: From other estimates I’ve seen, Lynas’ timetable seems about right if the goal is to avoid 450 ppm. To avoid 400ppm, even his timetable is a bit of a stretch. However, with regard to the impacts of exceeding 400ppm (or even 450ppm), if you are quoting Lynas correctly I would differ with his assessment. There is no magic threshold crossed at 450 that commits us suddenly to the kind of catastrophic changes you mention, and certainly not to extinction of humanity by 2100. If we can’t hold the line at 450, there are still harms to be avoided by stopping short of doubling. If we can’t stop doubling, there are still harms to be avoided by preventing tripling, and so forth. But his general sentiment that we can’t drag our feet on this is correct. –raypierre]
Wednesday, December 19, 2007
Here's a nice example of creative capitalism promoting efficiency: auto insurance based on miles travelled.
This is a very helpful idea for those of us who have to drive sometimes but don't like to or want to.
The entire enterprise has problems from top to bottom.
I've been talking about the proposal review process, and I have lots of pent-up frustration about the managerial process.
Linus Torvalds attributes the success of open source to following a scientific openness model, but scientists are closed and university legal teams are cagey and possessive of codes and methods, sacrificing science in their search for the jackpot patent.
In conversation last week at AGU, James complained about the value add in journals, the gatekeepers of science, being provided by unpaid volunteers while the huge financial transfers go to corporate entities mostly concerned with binding and shipping antiquated bits of paper that nobody ever actually looks at anymore.
Atmoz points us to an article lamenting the state of science journalism, which justifiably asks for more participation from scientists, indeed, much more.
Meanwhile, once something even a little bit technically subtle comes across the field of vision of the political sector, there are enough clowns in scientist costumes around to derail any remotely sensible policy.
All of these problems come down to communication; communication among peers, communication across disciplines, communication within institutions, communication with students, and communication with the public. Communication involves listening as well as speaking.
Scientists these days are scrambling to meet their perceived demands. We have little time to absorb the work of others, little time to design meaningful collaborations, little time to communicate. The fraction of achievement to unit work is grossly suboptimal. A few especially energetic and brilliant people manage to thrive, but their work is buried in the vast array of mediocrity that fills the paper journals.
It seems to me that we need to restructure the design of the whole system. We can't add new demands without loosening existing ones. There needs to be ways to fit in a range of talents. The emphasis on gathering information needs to be reduced in favor of vetting it and communicating it. We need more time to think and less time proposing to think. We need to think critically about others' work and generously about them as people rather than the other way round.
It's amazing how much gets done in spite of all this. Imagine what could be achieved if we weren't working with ridiculous antiquated managerial structures.
Update: Interesting, if only tangentially relevant musings here, again via Atmoz:
Even if cognitive enhancers had the potential to shift the standings in the competitions between students and between scholars to a dramatic degree, should we say that there's a problem with the use of these drugs -- or instead with the way the system is set up? Is it more unfair that some professors use a drug that gives them the mental energy to grade papers until 3 AM, or that the workload on professors is such that they have to stay up grading papers until 3 AM in order to have time to meet the obligations of their job?
Monday, December 17, 2007
There is plenty more to geophysics than climate, so there were three very accessible climate change talks in huge rooms at the AGU meeting in San Francisco last week. Of the plenary climate change talks, Hansen's got most of the press attention and perhaps Lonnie Thompson's got the most attention from the attendees, but I thought Richard Alley's was the most interesting and compelling.
Here's a slide of Alley's that I think presented nothing new to climate scientists, but that the public seems not to understand. The climate disruptions we are seeing now are very small compared to the ones we are worrying about. The importance of the past record is in confirming our understanding, but our expectation in business-as-usual scenarios is very much worse than a linear extrapolation.
Please also note that so far, we have been exceeding the steepest of the standard scenarios. Also note that as Dr Alley points out, the fact that the graphs traditionally end in 2100 doesn't mean the temperatures don't keep going up after that.
So what does a warming of 6 C portend? There's a book out about that called Six Degrees that you might want to have a look at. To give you an idea of the scale, warming over land is typically double the global average, and 12 C is about 20 degrees F.
Sunday, December 16, 2007
Then the delegate from Papua New Guinea leaned into his microphone.
"We seek your leadership," Kevin Conrad told the Americans. "But if for some reason you are not willing to lead, leave it to the rest of us. Please get out of the way."
The U.N. climate conference exploded with applause, the U.S. delegation backed down, and the way was cleared Saturday for adoption of the "Bali Roadmap."
See also the New York Times story.
Wednesday, December 12, 2007
See if this reminds you of anything, by the way:
Part of it was the usual bubble psychology. Economists like to cite Stein’s Law: “If something cannot go on forever, it will stop.” I think it needs to be paired with another law — let’s call it Glassman’s Law — along the lines of “If something unsustainable goes on for a while, there will be people claiming it can go on forever.”
And I know that when I began writing about housing, I got a lot of mail from people claiming that I was only saying that there was a bubble because I hated Bush. Honest.
Anyway, it’s just amazing. The reality of a housing bubble was staring us in the face — but nobody wanted to see it.
See whether you think he addressed my points.
Monday, December 10, 2007
Still, I don't think we should allow a conspiracy of number-averse journalists and political operatives prevent any serious quantitative reasoning in public discourse. It's time we grew up.
So I am very pleased to be listed among the blogs calling for a presidential debate on scientific matters, an effort kicked off by Chris Mooney and Sheril Kirshenbaum at Intersection which has garnered quite significant support already.
I'd actually like to see as many as four debates: science and education, engineering/energy/infrastructure. health/medicine, and ecology/environment/global change. That's asking for too much I suppose. Something would be much better than nothing.
Unfortunately I was in an airplane this afternoon and couldn't participate in the lifting of the "news embargo" at 2 PM EST. Let me stand up and be counted now; better late than never.
Let me also remind you of this snippet from the Texas Observer:
Geologist John Anderson says he’s tired of explaining the map, and the science behind it, to city officials. “If they do not understand it, they should not be in public office,” he says sternly.I think this general principle should apply to the head of state as well as to the Galveston city council, don't you?
Sunday, December 9, 2007
Here's an excerpt:
Ultimately, as the government heavyweights arrive in Nusa Dua, the truly key questions to ask – the answers to which form the crucible in which all the answers to all the other key questions must be tested – is whether our political leaders are serious about going far and going quickly on global warming. And whether we – Americans, Chinese, Balinese – are serious about making them get serious if they fall short.
With that in mind, let me recommend that one climate delegate from each of the 188 nations in attendance take an hour’s trip eastward from Nusa Dua along the coast to Candi Dasa. Pronounced chán-di-dassa, Balinese for "Ten Temples," it’s that little dot on the eastern horn of crescent Amuk Bay about two-thirds of the way to Bali’s easternmost point at Amed.
When the tide comes in at Candi Dasa, the concrete sea wall causes a rent in the water. At night the sea wall can look as black and solid as granite, and in the early misty morning light, pearly as a shell. By day, it is a blackened, rippling scar, an ugly reminder of what it replaced.
If you are familiar with the science you will recognize some of the signers of this declaration. The Nature blog has a bit more on this.
The 2007 IPCC report, compiled by several hundred climate scientists, has unequivocally concluded that our climate is warming rapidly, and that we are now at least 90% certain that this is mostly due to human activities. The amount of carbon dioxide in our atmosphere now far exceeds the natural range of the past 650,000 years, and it is rising very quickly due to human activity. If this trend is not halted soon, many millions of people will be at risk from extreme events such as heat waves, drought, floods and storms, our coasts and cities will be threatened by rising sea levels, and many ecosystems, plants and animal species will be in serious danger of extinction.
The next round of focused negotiations for a new global climate treaty (within the 1992 UNFCCC process) needs to begin in December 2007 and be completed by 2009. The prime goal of this new regime must be to limit global warming to no more than 2 ºC above the pre-industrial temperature, a limit that has already been formally adopted by the European Union and a number of other countries.
Based on current scientific understanding, this requires that global greenhouse gas emissions need to be reduced by at least 50% below their 1990 levels by the year 2050. In the long run, greenhouse gas concentrations need to be stabilised at a level well below 450 ppm (parts per million; measured in CO2-equivalent concentration). In order to stay below 2 ºC, global emissions must peak and decline in the next 10 to 15 years, so there is no time to lose.
As scientists, we urge the negotiators to reach an agreement that takes these targets as a minimum requirement for a fair and effective global climate agreement.
Saturday, December 8, 2007
In a brief article on DeSmog by Emily Murgatroyd, a Cato Institute type, Jerry Taylor, is quoted as saying
scientists are in no position to intelligently guide public policy on climate change. Scientists can lay out scenarios, but it is up to economists to weigh the costs and benefits and many of them say the costs of cutting emissions are higher than the benefits.Can we consider this claim, or is it somehow protected by a taboo? Is one a Marxist or even a Stalinist for pointing out that economists are not, themselves, necessarily, right about everything?
Climate science has been subject to a great deal of scrutiny, not all of it undeserved. I would be the last to claim that climate science is conducted impeccably and flawlessly. Though many of the problems are widely misconstrued, much of it indeed traces to motivational structures. At least we are constrained, though, by established physics.
Economists, meanwhile, claim to have the key to rationality. A claim in more desperate need of challenging I cannot imagine, yet on it goes, essentially unchallenged. Is infinite growth of some meaningful quantity possible in a finite space? No scientist is inclined to think so, but economists and their hypnotized victims habitually makes this claim without bothering to defend it with anything but "I'm, an economist and I say so", or perhaps more thoughtfully, "hey, it's worked until now".
You know, the gods of Easter Island smiled on its people "until now" for a long time, until they didn't.
The presumptions are so pervasive that great swaths of economic theory collapse in a singularity if a negative growth rate occurs. What, for instance, does a negative discount rate imply? Accordingly there is a presumption of growth the pervades everything. Even the Stern report, which is based on enough understanding of our circumstances as to see that unconstrained carbon emissions are to be avoided, has to torture economics a bit to come up with the result, and even so speaks of the consequences of failure in terms of "slowed growth".
Well, the cockroaches and jellyfish won't consider it a period of decline, I guess...
As for our species, we need a new economic theory.
Maybe what I'm saying would carry more weight if I formalized it a bit. How about this: everything economists say suffers from the bias of an implicit conditional. Two implicit conditionals in fact: economists provide advice presuming that growth is unlimited and that endless growth is desireable. They never bother to defend either condition on which their advice is based. (I think even the quantity which is "growing" is ill-defined.)
These conditionals were good approximations in the past. Once the finite nature of our world comes into play they become very bad approximations.
The whole growth thing becomes a toxic addiction. The only path to a soft landing is down; we in the overheated economies need to learn not just to cope with decline but to celebrate it. We need not just an ideology but a formal theory that can not only cope with reduced per capita impact but can target it.
I think the soft landing is still within our grasp. The longer we treat the people who call themselves economists as a priesthood above criticism rather than as a human subculture with serious dysfunctions, though, the bumpier the best landing we can achieve gets.
Climate change is just a symptom, though an increasingly salient one. The problem lies in our (humanity's) collective failure to consider what human decency means and to use that understanding to manage what money means. We don't have to listen to people who get that backwards.
Note: I submitted a somewhat clearer version of this to Grist. I'll let you know if/when it appears. Sunday evening: still not on Grist but here's a closely related article there by some other folks that I found very interesting.
Update 12/10: This is posted on Grist and is getting quite a few comments.
Update 12/11: "Tidal" offers us an immensely valuable link. (Thanks!) I am entirely enthusiastic about the contents of this talk by Josh Farley. He talks a bit too fast, which is a bit unpleasant, but that lets him get a lot in within a relatively short talk. I highly recommend it.
Thursday, December 6, 2007
Wednesday, December 5, 2007
I am getting my Second Life tonight (as soon as I come up with a name). Will keep you posted.
Climate scientists have a list of a couple of dozen 'essential climate variables' (see 'The dimensions of the problem') that they would wish to see monitored in perpetuity.The story they tell isn't a simple one, as some claim is the case with DSCOVR a.k.a "GoreSat".
However, it does seem like whatever you might think about climate simulation you probably ought to be in favor of data. This is slightly more important than Mars right now.
Tuesday, December 4, 2007
Yet, there appears in the health section an article about making healthier foods more attractive merely by renaming them. Apparently, for instance, "when regular peas were renamed 'power peas,' the number of children who ate them doubled."
Perhaps the problem is only that the truth has inferior marketing to the fiction.
Sunday, December 2, 2007
A short new briefing (PDF) from the International Institute Environment and Development (IIED) says that media coverage of climate change has improved, but ...It's time we started crafting a more nuanced message: yes, it's serious, but yes, we can do something about it.
"The false balance that has been a problem for years appears to be declining but a catastrophe narrative that disempowers people remains. Those supplying the media with information -- scientists, politicians and NGOs -- share some of the blame. The way they and the media frame climate change will affect how audiences respond."
Saturday, December 1, 2007
I'm going to say a word. You tell me the first thing that comes to mind. Ready?
What's that mean, "model"?
Did you hear the one about the software engineer, the climatologist, the psychologist, the statistician and the fashion photographer?
I am swearing off that word. It's got so many meanings. Any sentence with the word 'model' in it is likely to get you into trouble.
I'm giving the words "uncertainty" and "feedback" a very dubious eye as well. I am currently inclined to think they are also not usable in mixed company, but I'm not sure I can manage to go cold turkey on those. No, you shouldn't be too hard on yourself at New Year's.
Oh, and "error bars". What's up with that?
I never want to see those error bounds things again without a clear description of what you mean by it. "This is the manufacturer's spec on the measurement instrument" would be fine, but it's been a long time since I've seen one of those.
Does your error bar mean "that's how confused I think I am"?
I mean, seriously... Are you 100% sure that you're 75% sure of that? Rilly? What is that, an "imprimatur"? Do you guys get them from your spiritual leader or what? Because, you know, we don't get those.
Seriously, if I had some error bars I'd be slapping em on everything in sight; if you know how to detect a sure thing don't you think you should be out there making the most of it?
If science worked better, there would be a definition of the word "model" like that of the word "energy" which means something very specific in formal conversation, but there isn't such a definition. The word is a complete mess of vaguely associated concepts. I'm serious that dropping the word "model" from my vocabulary has greatly clarified my writing.
To climatologists looking askance at me here, the word you are probably casting about for is 'simulation'.
Want to know where that is? This map will draw your eye right to it. It's the place where the Antarctic surface elevation is dropping fastest. The current rates are not especially alarming. It's the lack of any obvious mechanism to constrain that rate from increasing by a couple of orders of magnitude that's the issue.
The base of this ice sheet is below sea level. That means the mechanics of its retreat is very different from the mechanics of retreat of land ice sheets. It is informed consensus that the very rapid sea level rise episodes of the not-too-distant past resulted from unstable decay of similar structures. A mechanism for abrupt retreat has been proposed.
Let me try to be clear. This is not to say that a couple of meters of sea level rise is imminent. It is to say that it might be relatively sudden when it happens, and that it might be imminent.
It's worth investigating and its worth modeling. I don't want to mess around in the politics of the situation too much, but it reinforces my distress about how science is funded to note that while the right people (I'm not speaking of myself, by the way; I would be pleased and lucky to be peripherally involved; I like being around people who are smarter than I am) are willing to do the work, there seems to be some difficulty identifying the "right pot of money".