Ray cogently argues at RC that the long lifetime of CO2 makes it more rather than less urgent to deal with CO2 rather than with shorter-lived perturbations. To the long-now view, to the science fiction reader, to the person who wants to see our planet prosper for another billion years and not just another century, this is cogent. But it's really a question of perspective.
I think we have to do what we can to avoid a crash; that is, a sudden decline in world population. Crashes (which have occurred on national scales) are very nasty times, and there are arguments that they tend to follow hard on the heels of periods of great prosperity. (See Jared Diamond's book Collapse.) This makes short-term perturbations of special importance. As I argued at RC
Hot on the heels of this exchange, I received another press release from Alexandra Viets making the case. (Other people should send me press releases, too. I have no compunction about just posting them!) And here it is:Two decades is the amount of time we need to buy to break even, as a rational carbon policy should have set in two decades ago. The way I see it is that the time we “buy” just compensates for our past foolishness, not for our future foolishness.
If I may be allowed a moment of armchair economics…
The foot-draggers say we should delay policy change for as long as possible because we will be wealthier in the future and better able to afford to act. The problem is twofold: 1) as long “as possible” may already have expired and 2) even in the absence of climate impacts, conditions have changed enough that future growth in per capita wealth along the model of the last 200 years is in no way guaranteed.
The reason to delay impacts for as long as possible (even at the expense of the long term outcome) is the flip side of this argument. At some point climate change may well become so severe that per capita wealth will begin a long term, accelerating downturn. At that point, no mitigation at all will be affordable. This argues for mitigation as early as possible because we can’t afford it once it’s too late; but it also argues for mitigation whose effects are as early as possible.
Cancun, Mexico, December 7, 2010 – Concern for high-mountain regions of the world is rising, according to a new report released by the United Nations Environment Programme (UNEP) today, which states that the Himalayas and many other glaciers are melting quickly, threatening lives by flooding, and by reducing the region’s freshwater supply. The findings of the report, “High mountain glaciers and climate change” were announced during the UN climate meetings in Cancun, where negotiators are working towards an agreement to reduce climate emissions.
The new UNEP data underlines the urgent need for climate action that will produce quick results – a topic addressed by a separate event today in Cancun, hosted by UNEP and the Federated States of Micronesia, a country calling for a fast-action work program to protect its low-lying islands and other vulnerable countries from climate change impacts.
The panel of scientists and policymakers, including UNEP Executive Director, Achim Steiner, and Mexican Nobel Laureate Mario Molina, emphasized the need to address non-CO2 climate forcers like black carbon soot, methane, tropospheric ozone, and HFCs to achieve fast mitigation.
Black carbon, a particulate aerosol produced from incomplete combustion of fossil fuels and biomass burning, directly contributes to glacial melt by settling on snow and ice, which darkens the surface and then absorbs the heat instead of reflecting it.
“The Himalayan glaciers are the main freshwater source for hundreds of millions of people across several countries,” said Durwood Zaelke, President of the Institute for Governance & Sustainable Development. “Fast mitigation of black carbon soot and other non-CO2 forces are the best hope to avert disaster.”
Because these non-CO2 climate warming agents are short-lived in the atmosphere compared to CO2, which can remain for hundreds to thousands of years, reducing them can buy critical time to make aggressive cuts in CO2 emissions.
Added Zaelke, whose organization focuses on the non-CO2 issue and is attending the meetings in Mexico: “Reducing CO2 is essential and we can’t lose that focus, but these are complementary measures that are within easy reach. We would be guilty of Planetary malpractice to waste this opportunity.”
Achim Steiner stated that reducing the non-CO2 forcers “can buy back some of the time” the world has wasted by not addressing CO2 earlier.###
It seems that embarrassment over the typo in AR4 WG2 has not slowed the Himalayan glacial retreat. I am, at this point, not sure what the time scale is for disruption of Asia's major rivers. I suppose AR5 will be reliable on that, there's one saving grace!
Anyway, Ray is quite right on the big big picture. I'm not going to criticize Ray on the science, not being a complete fool(*).
But as I see it getting through the bottleneck centuries is the real trick. And the less climate stress in the short run, the better. CO2 reduction is absolutely crucial but it has little short run payoff. I am not saying our distant descendants (if any) won't have quite a gripe against us. I think though that their gripe will be bigger the more spectacularly we drop the ball.
* Note: criticizing Ray Pierrehumbert on science does not ipso facto make you a complete fool. Criticizing him directly on climate science after hanging around him for a few years in a scientific setting, however, makes you either something of a fool or something of a climate science genius. I'm neither.
31 comments:
The quoted statement “The Himalayan glaciers are the main freshwater source for hundreds of millions of people”is a misconception, though it is very likely to be true if told as“... source for millions of people”.
Very regrettably, IPCC AR4 WG2 Chapter 10 (Asia) contained this misconception which can be traced back to a review article by Barnett et al. 2005: Nature, 438, 303 - 309 (which may not be wrong, but somewhat sloppily edited). Barnett et al. (also IPCC AR4 WG2 Chapter 3 (Freshwater resources) which cited it) showed population who depend on either snow melt water or glacier melt water. The number seems not so bad as such, but was misleading when transmitted to people who were interested in just glaciers.
A much better estimate of the vulnerable population has been made by Immerzeel et al. 2010: Science 328, 1382-1385.
(I have written about this issue in my blog in Japanese http://d.hatena.ne.jp/masudako/20100128/1264658100 . Maybe I will write an English version as a new posting of the same blog. I have also written about it as comments at SkepticalScience http://www.skepticalscience.com/Himalayan-Glaciers-Wrong-Date-Right-Message.html .)
By the way, an atmospheric scientist at NASA Goddard Spece Flight Center, W. (Bill) K.M. Lau, enthusiastically promotes the idea that black aerosols (soot), by absorbing solar radiation, modify atmospheric circulation and precipitation pattern of the Asian monsoon. I admit that the process he suggests must exist, but I am afraid it may not be so strong as he supposes.
It does make you a fool if you are criticising him about climate science on twitter and have never take a college level science course. I see plenty of examples of just that these days.
Oh, and I agree with you Michael.
ds
It seems that embarrassment over the typo in AR5 WG2 has not slowed the Himalayan glacial retreat.
(AR4 WG2, surely?)
No, but it is slowly deflating the number of people said to rely on Himalayan glaciers for water. '2035' wasn't the only howler in AR4 WG2 Chapter 10. The chapter put the number of people relying on ice-melt from Himalayan glaciers at 750 million, citing the Stern Review, whose cited sources said nothing of the kind. Subsequently, Chap 10 was cited as support for putting the number at 'one sixth of the word's population' (in a 2008 paper co-authored by Lonnie Thompson). Last month, Tim Flannery managed to get it up to two billion but on the whole the trend has been downwards since the Thompson paper. Thompson himself now talks vaguely of 'millions' being threatened. Your UNEP press release says 200 million. A recent paper put it at sixty million. It probably won't get much lower than that.
I should have re-read the UNEP pres release. It says 'hundreds of millions', not 200 million.
"At some point climate change may well become so severe that per capita wealth will begin a long term, accelerating downturn. At that point, no mitigation at all will be affordable." Exactly! Economists (e.g., Nordhaus and Tol) argue over what's the appropriate number for the discount rate regarding future environmental impacts - but they assume as an article of faith that the discount rate MUST BE POSITIVE. There is no basis for this assumption - it is not some sort of immutable natural law. Under a scenario of future decline in societal wealth it makes more sense to invest NOW in infrastructure you can afford now and that will be essential later (when that society can't afford to construct new equivalents of such infrastructure), as opposed to current spending on lattes and Hummers (ephemeral goods that don't add future social value). (Similar to the story of "The Ants and the Grasshopper" and all that.)
+1 L Carey. Thanks!
If you haven't yet, please be sure to say the same at RC.
I agree that this is a crucial misunderstanding that plagues all discussions on this matter.
Another thing to consider, I think pointed out once by John Mashey, is that a higher GDP as such doesn't necessarily provide you with the resources to do what needs to be done re: adaptation. Ipod production capacity doesn't help you build dikes.
Ray Pierrehumbert writes:
I can't post on "Gold" because I don't want a Google ID, or indeed any ID other than my own name.
Michael, just look at the graphs, will you? Doing "other things first" does not help you get through the bottleneck. What helps you get through the bottleneck is treating the accumulating poison (CO2) first, and then doing the non-accumulating poison later.
On soot, I actually think that anything we are likely to do on aerosols will wind up having huge human health and maybe regional climate benefits, but at best a neutral effect on global climate
Ray again:
... or another way of putting it is that "other things first" doesn't help you get through the
crisis. It delays the crisis, but makes it WORSE and MORE PERMANENT once it hits.
I reply:
Acknowledged. You make a solid case.
It's not the sort of thing I'd debate with you anyway; in a disagreement between me and you on such matters my own prior expectation that you are right is sufficiently strong that I capitulate first and ask questions second. But I don't think I was laboring under any major misapprehension in the first place.
What I'm saying is there are social / political / economic reasons to delay the crisis that arise outside the physics of the problem. At this point my claim is that we need delay of the onset curve rather desperately.
Any discussion of atmospheric carbon concentration over the next 200 years that does not include Arctic CH4 and CO2 is as worthless as a sea level estimate for the period that neglects ice dynamics. RP knows about it and talks about it, but Arctic carbon is not in his atmospheric budget.
It is OK to leave out such large factors as you build a theoretical model used for teaching purposes, but we have gotten to the point where it is time to do some real world engineering calculations to support real world decisions. Leaving such major factors out of real world engineering means that you get the wrong answer. Thus, RP's post and comments was a teaching exercise, and not something that is useful in the real world.
Our decision support models are not adequate to support any kind of a real world, climate policy decision/ or agreement. All of our decision support models leave out big factors that will bite us. I am not sure that no climate agreement is worse than a climate agreement based on models that do not reflect real world conditions such as Arctic carbon releases.
And, expect extreme weather events to destroy our capital resulting in a negative discount rate. We have started spending to repair extant, but vulnerable infrastructure. We will repeatedly repair and repair because the rational solution of abandon and rebuild is not politically feasible. We will waste resources repairing and patching, until we do not have the the resources to either repair or to build new.
+1 (at least) for Aaron.
I think a critical part of our evolving understanding of this mess we've created with both energy sources and climate change is how all the "parts" of these vast systems of systems interact. I put "parts" in quotes because viewing them that way is a purely human conceit, and it's just one more way in which the universe doesn't accomodate our preconceptions.
Some (most? nearly all?) of this need to play catch up with reality is understandable and stems from the inherently conservative nature of science. That's not a criticism; I shudder to think what mistakes humanity would have committed without that governor on our enthusiasm.
As for the basic question -- focus on CO2 or the "other things" first, I'm not convinced we know enough to answer it accurately. Every time I've convinced myself the answer is A, I read something that makes a compelling case for B.
The fact that millions of people crucially depend on glacier melt water should not be dismissed. I mean that the number is not hundreds of millions or billions.
It is also true that two billions of people in total live in catchments of rivers (including Ganges and Changjiang=Yangtze) which have glaciers in their "headwaters" in Asian highlands, and that a large fraction of the people depend on water of the rivers. If the climate of Asian highlands change considerably, it will have some effects in lives of people downstream.
But, it is a popular misconception that river water comes just from a locality which is conceived by people as its "headwater". A river is a system that integrates rainfall and snowmelt (also glacier meltwater) all over its catchment.
Hmm, a quick stroll through Google Scholar seems to indicate that this issue is getti8ng a fair amount of attention. Note the last sentence in particular in the abstract of this recent paper:
"Reversible and irreversible impacts of greenhouse gas emissions in multi-century projections with the NCAR global coupled carbon cycle-climate model"
"The legacy of historical and the long-term impacts of 21st century greenhouse gas emissions on climate, ocean acidification, and carbon-climate feedbacks are investigated with a coupled carbon cycle-climate model. Emission commitment scenarios with zero emissions after year 2100 and 21st century emissions of 1,800, 900, and 0 gigatons of carbon are run up to year 2500. The reversibility and irreversibility of impacts is quantified by comparing anthropogenically-forced regional changes with internal, unforced climate variability. We show that the influence of historical emissions and of non-CO2 agents is largely reversible on the regional scale. Forced changes in surface temperature and precipitation become smaller than internal variability for most land and ocean grid cells in the absence of future carbon emissions. In contrast, continued carbon emissions over the 21st century cause irreversible climate change on centennial to millennial timescales in most regions and impacts related to ocean acidification and sea level rise continue to aggravate for centuries even if emissions are stopped in year 2100. Undersaturation of the Arctic surface ocean with respect to aragonite, a mineral form of calcium carbonate secreted by marine organisms, is imminent and remains widespread. The volume of supersaturated water providing habitat to calcifying organisms is reduced from preindustrial 40 to 25% in 2100 and to 10% in 2300 for the high emission case. We conclude that emission trading schemes, related to the Kyoto Process, should not permit trading between emissions of relatively short-lived agents and CO2 given the irreversible impacts of anthropogenic carbon emissions."
What's being suggested sounds to me like it amounts to such a trade.
Michael, could you do me the favor of re-stating your position? There's been so much back-and-forthing I'm not sure I have it correctly. Thanks.
No offense, but after I read the Wendell Berry quote I knew everything else would have to be a relative downer, so I stopped there.
The more Wendell quotes the better, and some Robinson Jeffers and John Muir wouldn't hurt the cause either.
Regarding the number of people living downstream of glacier freshwater resources, Kaser et al (PNAS, 2010) have an interesting approach. From their abstract:
"By comparing monthly glacier melt contributions with population densities in different altitude bands within each river basin, we demonstrate that strong human dependence on glacier melt is not collocated with highest population densities in most basins."
Basically, its about location, location, location. The Indus and Ganges and Ibasins have large populations (211M and 449M, respectively), but mostly at lower elevations where the glacier contribution to streamflow is moderated by rainfall and snowmelt inputs.
Kooiti, I don't know if your second comment was aimed at me but I'll say this anyway: I don't think millions of people losing an important source of water is a minor issue but it is a far smaller problem than if billions are threatened and I'm fed up with what is, in some quarters, a *systematic* exaggeration of the likely impacts of climate disruption. These people aren't saying that billions of people rely on rivers whose headwaters happen to be in the Asian highlands; they say (or strongly imply, which is in some ways worse, because it suggests that they know it's bunk) that ice-melt from the Asian highlands supplies billions of people with all or most of their water. Last month, Tim Flannery warned of 'two billion people in Eastern and South asia without water due to the loss of the Himalayan glaciers'. This month, The Asia Society released a video in which Bill McKibben and Orville Schell strongly imply the same thing. In July, Syed 'Never Said 2035' Hasnain warned that future reductions in ice-melt from glaciers and permafrost in the Himalayas and on the Tibetan Plateau 'will be a big catastrophe for the entire communities there, which are more than 1.5 to two billion people, which are directly dependent on these water resources'. A 2010 'factbook' from Wetlands International: '... more than 2 billion people in South, Southeast and East Asia rely on glacial melt water.' The Worldwatch Institute, 2009: 'Glacial melt provides as much as 70 percent of the summer flow for the [Greater Himalayan] region's 10 major river systems, supplying a large share of the water needs for an estimated 3-4 billion people downstream.' These are big players in the climate game. They have privileged access to governments, which take their views very seriously. But they're talking rot.
As for a changing climate in the Asian highlands having some effect on the lives of those living downstream, isn't the net effect likely to be beneficial? Less ice-melt arriving when it's not really needed (Pakistan excepted) and more snow-melt arriving when it is needed? I can't remember where I read that and would be grateful if you could point me towards any relevant research.
(Incidentally, your first comment wasn't there when I posted mine.)
Vinny, broadly speaking we would also expect less snowfall as the glaciers recede. Even with constant precipitation, that will lead to big trouble in the dry season, but as we are seeing here in the western U.S. reduced snow may also be linked to reduced precipitation. Even if it's not, a bigh reduction in glaciers and snow will mean big trouble for places without an ability to store enough water to get through the dry season (where that correlates with the summer high glacial melt season, which isn't everywhere). Note that the Chinese have a crash program to create such an infrastructure, while others in the region are in no position to do so. Also note that groundwater isn't immune from these changes.
I agree that overstatements aren't good, but are you equally bothered by the understatements of other climate-related problems?
If everybody bends over backwards to be fair, what is left is pretty scary.
So I recommend everybody bending over backwards to be fair.
SB: 'I agree that overstatements aren't good, but are you equally bothered by the understatements of other climate-related problems?'
Not equally, no. On this side of the pond, the exaggerators have far more influence than the understaters and, when faced by relentless, officially sanctioned doom-mongering, much of it implausible, there's an irresistible temptation to try to redress the balance by understating the problem. (I might have been guilty of this every now and then.) Also, exaggerating science while claiming science as your authority (as many NGOs and individual activists do, ad nauseam, no matter how misstated or cherry-picked their claims) is far more irksome than simple ignorance.
Vinny, note that Michael has to keep repeating the point that science (or at least the public understanding thereof) has a tendency to understate the problem. Is it clear to you why this has to be the case?
Speaking of the Himalayan region, these recent <a href="http://search.japantimes.co.jp/cgi-bin/eo20101209mr.html>results</a> on its climate history are interesting. Let's push our luck, right?
In the last couple of years I recall seeing reports of rapid drying/desertification up on the plateau, although I don't know if these were more than anecdotal. What I kinow isn't just anecdotal is the extensively documented drying to the northeast of the plateau.
As noted above, the Chinese are in the process of putting in place an extensive water storage infrastructure to catch run-off from the plateau. It's interesting to see how a society essentially run by people who trained as engineers responds to the impending crisis, whatever else one might want to say about the Chinese government.
SB: 'Is it clear to you why this has to be the case?'
Yes and no. Proper science should neither understate nor overstate. It should give a range (when appropriate) and tag the extremes with probabilities.
But I know what you're trying to say and, yes, I do get it. But how much prudent and methodologically correct scientific caution gets you from millions to billions?
Then there's proper science being routinely abused by governments and (other) activists. Civilization doomed unless... Mankind doomed unless... Even the planet itself doomed unless...
I'm sick of it. There's no scientific justification whatsoever for saying, again and again and again, that the extinction of Himalayan glaciers would leave billions short of water. Nor is it likely, let alone certain, that meteorological drought will affect half of the world's land surface by 2100 (or half of the world's surface, if you believe The Times). Sea-level rise? A bummer for a few places, yes, but how far should six billion people go to allow Tuvalu's 11,000 to continue living on an international dole? A loss of global agricultural capacity because rainfall moves around a bit? Horseshit.
There's no common sense in the climate 'debate'. Climate disruption is but one future disruption among many and, given the vast disruptions caused by other factors in the last century, AGW's tiny trends are unlikely to loom large on a global scale in the next. If they do - well, we'll deal with it and thank our gods that worsening weather was all we had to cope with.
Slow down a moment, Vinny. Did you see Kooiti's comment where he attributed the problem to a conflation of snow and glaciers? As I noted, in the real world they don't tend to be separate. That said, people need to be precise in order to avoid confusion, and some people have been careless.
BTW, you might want to check out the situation in the northern Andes, where the precip changes have already happened and the run-off dependent regions are looking at complete desolation when the glaciers finish melting.
Australia in the last five years is a good example of how you can get overall drought even with an increase in the hydrological cycle. Note that both extremes do a fine job of trashing agriculture. Note also these recent observations of a drop in global NPP. Due to the shortness of record we can't tell for sure if this will continue (or more accurately if the drought trend driving it will), but it is very much consistent with the drought projections you complain about.
I should add that by now studies of past climate (in particular the mid-Pliocene and -Miocene warm periods) tell us with good certainty the sort of climate state we're headed toward if CO2 levels go up and stay up. If they go up fast enough we have some risk of locking in a repeat of the PETM, which I would prefer to avoid.
But beyond that, since we are pushing the climate system much harder than was the case even leading up to the PETM, we have a risk of entirely unnatural feedbacks like the "compost bomb." These could push us into a PETM-like excursion very quickly, and under those circumstances I suspect the fact that we still have a bunch of ice in place will cause things to go very badly for us. Notice that I haven't even mentioned ocean acidification.
But I'm glad your intuition tells you that this stuff can't be a very large problem. It's just that I hear differently from scientists.
Steve, I don't think that there won't be very large problems here and there. I do think that there'll probably be larger problems and that continually hyping climate change as the greatest threat to civilization, mankind and the planet is daft - mostly factually daft, because such extreme hype has no scientific basis and ignores other aspects of human history (our viciousness, our resilience), but also, from your point of view, tactically daft. Chicken Little etc.
Anyway. Specifics. In which sense do snow and ice not tend to be separate? Snow melts first, which means it arrives in the most populous areas before glacial melt - months before, in the case of Greater Himalayan melt-water. Sad though a drier Andes might be, it has no particular relevance to long-term snow-melt trends on the Top of the World. Any pointers to relevant recent research about those? A review-paper would be better than a one-off and something that includes projections of monthly river-flows in the most populated areas would be terrific. If the paper says that snow-melt will probably decrease overall or will arrive at the wrong time or will be a temporary manifestation of a gradual but catastrophic reduction of the snow-pack - that's fine with me. I just want to know where the science is at.
NPP, Australia and drought. I'm stale on all that. I'll just say that I do understand how more rainfall doesn't always mean less NPP - and also how less NPP doesn't always mean less agricultural productivity.
The Pliocene. Pass.
Compost bombs. Informed conjecture about worst-case possibilities for particular biomes is useful as a planning tool but it's not a snapshot of the future of everywhere (or even of that particular biome). In this particular case, I can't even see how the papers mentioned in that press release could have anything more than a very local significance - but then they're pay-walled. Do you have links to the full papers?
(Checkword: 'barkengs'. How unkind!)
More on future drought for the U.S.
'I'll just say that I do understand how more rainfall doesn't always mean less NPP...'
Er, 'more NPP...'.
"I just want to know where the science is at."
"The Pliocene. Pass."
Sure, Vinny.
Thank you, Joe. I have read the paper of Kaser et al. Though their "population index" is just a crude index, my order-of-magnitude guess of "millions of people" seems confirmed. I think they somewhat (though not very much) under-estimate importance of glaciers as water resouces in monsoon regions. With glaciers, people can hedge against interannual variation of precipitation. Kaser et al. used climatological (30-year average) monthly data, so they could not account for interannual variations.
Post a Comment