A recent paper by Oreskes et al. in the journal Philosophy of Science asserts that “there is a gap between the scale on which models produce consistent information and the scale on which humans act”. While the large scales, such as the global mean, provide the best indicators of the state of earth’s climate, it is on the local scales we feel a climate change, such as floods and extreme weather events. Extreme rainfall is usually local. So how is it possible then, as two new papers in Nature by Min et al. and Pall et al. (discussed here) have done, to attribute extreme precipitation and extreme UK floods to climate change?
First of all, Oreskes et al. emphasize that the reality of mean global warming is essentially undisputed, but that the future impacts on the scale for which humans would have to prepare are still the subject of considerable research, inquiry, and debate. Moreover, they argue that climate models do not give us the information we would need to accurately estimate the costs of adaptation and effectively prepare for the consequences of climate change – successful adaptation to future climate changes depends on whether the models produce realistic projections for regional and local scales.
We have already discussed why climate models are not well suited for providing detailed information about local climate on RC (here and here). It is important to keep in mind that models are only approximate representation of the real world, and that they are only meant to capture the essence of our climate – i.e. the larger picture. There will always be a limit to the degree of detail for which the models fail to produce reliable and useful information, and the interesting question is where this limit is. It’s a question of limitation rather than flaw.
There is a difference between the spatial scales associated with a local point measurement and statistics based on many local values. When looking at the statistics for a large region, one could argue that these studies do not rely on local scales. In fact, Min et al. used leading empirical orthogonal functions (EOFs; a type of principal component analysis) in their attribution analysis for extreme precipitation, implying large spatial scales. Hence, the points raised by Oreskes et al. may perhaps not be directly applicable to the attribution study done by Min et al.
Pall et al., however, involved statistical downscaling to bridge the scaling gap between model and real world. Oreskes et al. paper argues that even with downscaling, our information about local scales is incomplete. Hence, the points raised by Oreskes et al. may be more relevant for the study of Pall et al. – and indeed for several of my own papers (e.g. local temperature scenarios available for viewing in GoogleEarth described in a forthcoming publication).
So, does that mean that downscaling is worthless? No! We already know that the local climate is systematically influenced by many factors, such as latitude, distance from the coast, and altitude. This information can also be utilized in the making of local climate projections – and this is exactly what is done in most downscaling exercises. The question is whether the additional information, such as that provided by the GCMs about future trends, is reliable. If the downscaling involves more than just getting a number for the future, but also evaluation over the past and other diagnostics, then I think there is some value in the downscaling.
I will argue that the uncertainties make it necessary to look at many different methods for downscaling (regional climate models and statistical downscaling) as well as the largest possible range of (sensible) GCMs. Nevertheless, the problems raised by Oreskes et al. are deeper than just looking at more models and more methods. Downscaling future climate involves uncertainties from a range of sources, some better known than others.
Another issue is the attribution of extremes to climate change, and the difficulties associated with these. We have already said that it is impossible to prove that one event is due to a climate change (here). A climate change involves a changing weather pattern, and if one event is part of an emerging new pattern – a trend – then one may with hindsight say that it fits the picture. Time will show.
Obviously, care must be taken, and downscaling studies that do not appropriately account for the real range of uncertainties may risk ‘over-selling’ the results. In the rekognition of the uncertainties, the IPCC Good-Practice-Guidance-Paper on using climate model results offers some wise advice (first bullet point under section 3.5 on p. 10): the local climate change scenarios should be based on (i) historical change, (ii) process change (e.g. changes in the driving circulation), (iii) global climate change projected by GCMs, and (iv) downscaled projected change. By putting the local climate into the context of the larger picture, analyzing the uncertainties, and evaluating the methods in terms of past changes, I think that local climate projections can provide useful information. However, applied inappropriately, downscaling can also be deceptive.
In any case, Oreskes et al. make a strong case for the need of curbing the emission of GHGs. But I also think it is important to increase our efforts in making further progress in terms of our ability to get a clearer picture of how a global warming may affect the local climate and what that may mean for adaptation.
Very substantial subject for the long-term policy decisions. I agree with the insufficient information on local weather changes and also the importance to increase our knowledge.
But isn’t it the time for us to prepare both “adaptation” and “mitigation”? Overstressing the uncertainty would postpone our decision and make our effort “too late”.
It seems to me that the available knowledge today is not sufficient to evaluate the cost-benefit precisely, but enough to give the priority of our options. “No act” is already deleted from the list.
I think “both” is is the key word here. Uncertainty is not an obstacle the way I see it, and we can include that in planning – that is what is done in all risk analysis. Uncertainty is everywwhere, and we deal with it all the time. But that doesn’t stop us… -rasmus
AFAIK the UK government is planning adaptation and mitigation. Although my impression is that adaptation policies are probably more enthusiastically adopted because they are politically easier to sell and can be financed via short term budgets that the democratic process can handle.
From what I can make out, in the change from a Labour government to a largely Tory coalition (right wing), ‘green’ policies have remained intact. Especially when compared to the cuts in many areas. Something for American politicians to learn from?
Interesting timing, week long flood adaptation exercises (Exercise Watermark) this week in the UK:
http://www.bbc.co.uk/news/uk-12661471
A very interesting and timely article. One issue I have is that in any risk mitigation exercise, the first essential step is to bound the risks. If you cannot bound the risks, you cannot allocate resources effectively. Unfortunately, there are many factors that preclude an effective bound on the risks–ranging from uncertainties in downscaling to more fundamental issues such as the uncertainty of climate sensitivity. The consequences of climate change rise dramatically with sensitivity, so unfortunately the extremes of the sensitivity distribution wind up driving risk calculus, even though most of us don’t believe sensitivity is as high as 6-10 degrees per doubling.
Moreover, the extremes of a distribution will always be the most poorly constrained portion, and looking for trends in the extremes is bound to be an even more fraught proposition.
If faced by a risk calculus in my day job, I would take one look and suggest that avoiding the threat is the only viable option. Unfortunately, humanity appears to have taken that option off the table. We have left ourselves no choice but to design for a very different future we can only dimly glimpse.
But shouldn’t we do something even if we are not able to bound the risks effectively?
Even if we have to live in a very different future we should try to keep the differences as small as possible.
Another global indicator that is projected to increase is sea level. I’ve read, in the mainstream media, about various local efforts to plan for sea level rise but these articles only mention the global sea level rise estimates. My question is do scientists have reasonable estimates of how level sea rise will be distributed? If so, is this information being used?
Thank you, Rasmus. Could you comment on how this applies to the drought projections by Aiguo Dai of NCAR, found here:
http://www2.ucar.edu/news/2904/climate-change-drought-may-threaten-much-globe-within-decades
I have used this to illustrate the seriousness of the climate change threat, but I am a little uncomfortable about the methodology. As I understand it, he combined regional projections of rainfall with regional projections of temperature, to obtain regional projections of PDSI, using the means of multiple runs. That would seem to create pretty wide error bars. Still, I suppose it it useful to know the “mean” PDSI produced by the two means of rainfall and temperature. Sorry to be so vague about this – it is because my understanding is so vague.
The discussion is cautious and tries to account for uncertainties, e.g. by looking at an ensemble of 22 computer climate models and a comprehensive index of drought conditions. The analysis also follows the advice in the IPCC Good-Practice-Guidance-Paper on using climate model results: the local climate change scenarios should be based on (i) historical change, (ii) process change (e.g. changes in the driving circulation), (iii) global climate change projected by GCMs, and (iv) downscaled projected change. We do have some information about historical change and we do have a physical picture of process changes. In the end, there are lots of uncertainties, but studies like these go a long way to elucidate the situation – according to the best information that we have. -rasmus
Knox,
The problem is not WHETHER we should do something, but WHAT we should do. If sea level rise is going to be manageable, we can focus efforts on barriers, improved wetlands, etc. If not, we should focus on evacuating low-lying areas.
If increased drought were to be a minor threat, we might focus on improved water retention and farming techniques in existing agricultural areas. If it is as serious or moreso than thought, we will have to develop entirely new food crops.
Severe weather, river flooding, heat waves, drought, sea level rise, increased pests and disease and on and on–we cannot defend against the worst case for every threat. Without a bound on the consequences, we don’t know where to focus our limited resources.
“Adaptation” normally means evolution by natural selection. Evolution by natural selection means that new mutations are selected and the prior species average dies out. Natural selection is always accomplished by mass death. Oreskes, Stainforth and Smith are misusing the word “Adaptation.”
People “accentuate the positive” in adaptation, and emphasize the growth of the new or modified species. That is fine when it was a long time ago and not us. In our own case, Oreskes, Stainforth and Smith are assuming that no natural selection need take place. I suggest that they invent a new word that means what they want to say. “Adaptation” isn’t it.
For Mike (#7):
http://www.google.com/search?q=site%3Arealclimate.org+regional+sea+level+rise
http://www2.ucar.edu/news/2904/climate-change-drought-may-threaten-much-globe-within-decades
doesn’t show the worsening floods in 2008-2010 in northern Illinois.
I agree with Ray Ladbury, the key problem here is to do a decent risk assessment. When you are doing risk management you prioritize risks by multiplying their probability with there expected consequence. In the case of climate change, risks are largely loaded on the worst case hypothesis. This as been supported by a few economics analysis.
Hence, the rational think to do would be to plan for those extreme risks. But a this point, the unknown is very large, which means the worst case is really really bad. So bad that is psychologically unpalatable. Any experience engineer will tells you that in such situation most managers with have a tendency to reject the risk estimation since it is too pessimistic.
We all know what is the typical consequence of such behaviour.
“Safari can’t open the file “esd.google.earthTemp.kmz” because no available application can open it.”
What is this file and what can I do with it?
Mike,
Historically, past sea level changes analyzed by NOAA have shown significant varations in measurement. The highest observed changes have been in the Japanese and Phillipine islands. The greatest sea level decreases have occured in and around Scandinavia. The two areas will proabaly continue to lead due to glacial rebound and tectonic movement.
Other areas of pronounced increases include the east coast of North America and New Zealand, while decreases have been measured throughtout Alaska.
The Pacific Islands need each be considered individually due to different factors affecting each island. Islands such as Guam and Tuvalu have actually shown a decrease in sea level, while others such as Wake, American Samoa, and Tonga have shown shown large increases.
How this information is being utilized, I cannot say. Hope this helps.
In looking at a wide range of possibilities and attempting to weigh uncertainty with preparedness verses cost, I think that the a careful consideration of the precautionary principle provides a basis for adaptation on a regional basis.
Farming practice, localizing food production, flood management, extreme snow events, water management, sewage handling are all important infrastructure areas of consideration. In some of these cases, adaptation in efficiency of handling would benefit us whether we had climate change or not.
That is, in my mind, a good basis for some decision processes. ID deficiency in areas where there is overlap weighed against potential risks to cost/benefit, and focus funding in those areas.
The US Navy Arctic model (Maslowski) sets a different time line. The Navy model at first looks like a simple extrapolation of the decline of ice volume, but there is a supercomputer model behind it – not a global model but a more detailed model of just the Arctic region. Ocean heat is the main driver of ice reduction for sea ice and glaciers that run to the sea. If the Naval model turns out to be right, it effects all the other projections. This ought to be part of bounding the risk. Is there any reason why the Naval model is not included in multimodel studies?
Ray Ladbury: If sea level rise is going to be manageable, we can focus efforts on barriers, improved wetlands, etc.
The total miles of coastline is daunting.
This is really the first time in human history that we have had the opportunity to proactively adapt to future changes. The problem is that downscaled information is never going to have all the answers, yet, there persists this idea that once we have higher-resolution information we will have what we need to act on adaptation. This is simply untrue. Especially when you start looking at variables like extreme rainfall, the projected amounts completely depend upon the downscaling technique and the climate model. That’s not to say downscaling cannot be useful, but sometimes I think it has been oversold to decision-makers and we need to be drawing more heavily on the social sciences to work out how to make decisions that will robust under a range of possible futures.
Rasmus – nice post. I’ve been browsing the Google Earth trajectories, and one puzzle arises (which I can’t resolve as I haven’t gotten to the paywalled paper). A spot check of many of the A1B station scenarios (Red Lodge, Berkeley, Salamanca, Pusan, Sydney, etc.) shows that the rate of increase of temp slows a lot at the end of the century. I don’t recall seeing that in global A1B scenarios (e.g. http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch10s10-5-3.html ). Is that the real outcome, or is it just an artifact of looking at too few stations, or perhaps a smoothing boundary assumption? – Tom
Tom Fid: Good question. I haven’t got to the bottom of this yet, but there are several plausible explanations: (i) some of the simulations in the downloaded models from the CMIP3 ensemble stop early, affecting the whole envelope of results, (ii) the use of common EOFs fail to capture large-scale temperature patters that are too different from the past. So my guess is that it’s a likely artifact. -rasmus
Excuse my ignorance, but are there ways to usefully combine climate models and weather models? Say, for example, use GCM’s to estimate an increase in humidity, then run a weather forecasting model allowing for that increased humidity. Would that return any useful info? I’m sure someone’s thought of this already!
for Edward Griesch: http://www.google.com/search?q=google+earth
The biggest risk in preparing for climate change has nothing to do with climate. The biggest risk is economic. We can predict climate with modest certainty, but we can’t predict future economies and technologies at all (note the unpredicted nature of both the recent economic meltdown and the digital revolution). Given infinite resources and infinite knowledge of future technological developments, we could prepare effectively. But we have neither.
If we prepare for climate extremes by employing high cost / inefficient technologies immediately and lower cost / more efficient technologies emerge in the near future, we risk a significant economic setback – which will appear more pronounced if climate extremes do not materialize. OTOH, if we do nothing and the extremes do materialize, we risk the same result.
We should think of climate change mitigation as an investment for which the fair price and future yield is uncertain but presumed positive. To get the most out of our limited resources, we average in.
Spend heavily on the currently most economically/GHG efficient mitigation technologies (IMO, hybrid transpo and nat gas/nuke electrical gen), and increasingly phase out the most GHG inefficient technologies over time (coal). Spend modestly on implementing barely economically efficient technologies (wind), and sparingly on economically inefficient technologies (solar), but commit research dollars to all promising but economically inefficient technologies (solar, wind, tidal etc). Adjust priorities as technological change demands.
Loosely relevant, but the UK government has been reported to be giving higher priority to get the UK off oil dependency for its energy needs as a matter of national urgency, not provoked by climate change but by ongoing events in the Middle East. It includes getting us on a low-carbon pathway, promoting a national infrastructure for electric vehicles, deadlines for building low-carbon homes, Greenpeace being asked to monitor progress. China is also used as an example of what’s coming in terms of alternative energy sources.
http://www.guardian.co.uk/business/2011/mar/05/oil-uk-energy-sources
Every cloud…, I suppose.
One Event
I think care is needed in claiming that one event can’t be attributed to warming. The example of hurricanes is a good one for saying this. One strong one is neither here nor there in terms of warming. But what of an extended record heat wave? It is one event because we call it so, yet fractional attribution may be possible. What of a multi-decade drought? Again, it is one event because we call it so, but now it is stretching into a timescale over which climate is measured.
It can lead to confusion if the possibility of attribution is dismissed too reflexively.
Came across this story today, and it seems pretty on-point for this thread. Won’t have a chance today to check out the study itself; perhaps someone else will want to bird-dog it for us?
At any rate, Feng et al. say in a new “Climate Dynamics” study that “By the last decades of this century, only small, scattered patches of tundra are expected to remain along the mainland Arctic coast,” replaced by boreal woodland. (Although tundra should persist in the Arctic archipelago and may expand in Greenland as the ice cap shrinks.)
See:
http://www.montrealgazette.com/news/canada/greening+North+climate+change+shrinking+tundra+says+study/4387983/story.html
“. . . mainland [North American] coast,” that is.
http://trove.nla.gov.au/work/36571015#
Making climate change work for us : European perspectives on adaptation and mitigation strategies / edited by Michael Hulme (2010) Cambridge University Press
Aside: public policy by asking the public:
http://www.public-consultation.org/studies/budget_feb11.html
“a decent risk assessment”:
We already have a decent risk assessment. The biggest risk is NOT economic. Sea level rise is irrelevant to the greatest risk. Our own Bart Levenson told us everything we need to know. The greatest risk is the collapse of agriculture due to drought.
Without agriculture, there is no civilization. Without civilization, there is no need for port cities on the seacoast. Without agriculture, there will be no people to populate the cities. It seems to me that at least some of the commenters are in psychological denial of the biggest risk. Sorry, but it is time to concentrate on the biggest risk and forget about minor details like sea level.
“downscaling”: Lack of downscaling gives denialists one more weapon since Dr. Aiguo Dai’s maps show my location as dry in 2008 when we had 3 floods instead of 1. We do not need downscaling to know what to do. What to do is mitigation. We need downscaling to get the present weather right so that denialists will not have this weapon.
@One Anonymous Bloke: GCM’s and NWP models?
http://ecearth.knmi.nl/index.php?n=PmWiki.Visualization
Extremely pessimistic overview of current arctic sea ice formation and disintegration processes and the current sea ice state.
I’m sure the wildlife will adapt to this just fine.
Thank you to those who elsewhere provided links to the recent issue of the Philosophical Transactions of the Royal Society. One of the articles in that issue presents what I found to be an helpful discussion about adaptation strategies.
From the abstract: “. . . In this paper, we show how complexity and uncertainty can be reduced by a systematic approach to categorizing the interactions between decision lifetime, the type of uncertainty in the relevant drivers of change and the nature of adaptation response options. We synthesize a number of issues previously raised in the literature to link the categories of interactions to a variety of risk-management strategies and tactics. Such application could help to break down some barriers to adaptation and both simplify and better target adaptation decision-making. The approach needs to be tested and adopted rapidly.”
http://rsta.royalsocietypublishing.org/content/369/1934/196.full
Arjan #31 Thank you very much. Another mountain to climb :)
Adaptation only means evolutionary adaptation is specialized writings:
http://www.merriam-webster.com/dictionary/adaptation
It is compleely within the usual meanings of the word to refer to human responses to changing climate.
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Live preview works fine for me… on a Kindle, at that. The missing jQuery is something I have noticed too, but it doesn’t seem to break anything visible to us readers.
Adaptation is a myth. We are having some theoretical discussion that has no connection with actual future events, and human responses to it. People will be on the move on a massive scale and that’s about the only adaptive measure that I see happening long-term. But let’s just assume that adaptation is real. What are the options? Turning up your AC, learning how to get out of your car quickly in case of a flash flood; stacking up on canned goods when crops fail; getting to a shelter quickly when that tornado strikes in places where it’s never struck before? I have heard people talking about growing vegetables in their basements. I can’t even believe that anyone would make such a suggestion. Who even came up with the notion of adaptation or resilient communities in the first place? It’s horridly cynical at best (some of us will survive because they can turn up the AC) and dangerously stupid at worst. Someone please debunk the whole notion since that’s apparently necessary.
Live preview works for me [Firefox/Linux].
Rasmus, thank you for your thoughtful, very helpful response (10). It gives me confidence to move ahead with Dai’s study. If his results are even close to being right, we are likely to have great trouble producing enough food by mid-century.
23 jimster,
I share your judgment about priorities, though you could include some other measures.
My list includes much of yours, but I also see (1)reason to look further into stimulating plankton growth in the oceans, and(2)establishing standing forests with water made available by re-distribution of water on a continental basis, at least in North America. (3)Continuing with improvements in insulation has significant quantitive potential. Also of potential large magnitude benefit, is(3)changing away from an electric power generating system where power plants are located in remote areas but are connected by a grid, whereby this practice has caused a massive energy wasting establishment. We also might note that motor vehicles, these being both cars and trucks are second only to electric power generation when it comes to CO2, and these could be vastly improved by rejecting standard automotive practice and insist that cars be aerodynamically efficient like well known airships.
Sorry, my numbering plan got lost in the flow of things.
Edward (13), what is your point (if you have one)?
44 Ron Taylor: See 30.
I endorse 39 Lisa McFadden. What is happening all across the north coast of Africa is stage 1 of GW adaptation, accepting merriam-webster. Notice that Europeans are keeping the Africans out, so far without violence. That will change. Adaptation means killing the excess population, just like in Rwanda. Mitigation is the only reasonable thing to do, but it has to start several decades in the past.
Lisa @ 39 Who even came up with the notion of adaptation or resilient communities in the first place? It’s horridly cynical at best….
Very good point. We personally (unless some real youngsters are reading this) are not personally the ones who will have to “adapt” to high heat, drought and flood and low resources of all sorts.
Do you think maybe we should stop burning carbon like there’s no next generation?
Jimster @ 23, No to natural gas. It is methane and it leaks. Recalculate your economic efficiency of energy sources. The official cost is based on considering some “external” costs, but not the Big One, or else fossil fuel would be priced out of the market by a mile. Compute real costs and put the upfront money into non-carbon power. If nuclear, use thorium molten salt reactors to avoid excessive water use. And by the way outlaw watering lawns. Adapt! Get over your grass!
Instead: 1) mandate net metering everywhere. (meaning those with solar power can sell power to the grid as well as buy it). Make homeowners aware that with solar on the roof to power an electric car in addition to the lights they come out ahead in time. Apartment dwellers,if they object to the up front cost of power, can move closer to work. There’s adaptation for you. 2) Mandate bike racks in addition to handicap parking. Make everyone healthier. Adapt!
3) leave reduced carbon in the ground.
Edward, I had somehdow missed your 30. I doubt that Dai would defend as predictions the results of his analysis for a specific point on earth in a particular year. Rather, I think it is the maps showing decadal averages that are most meaningful. But, in any case, I quite agree that the collapse of agriculture is the great threat, and we should place a high priority on genetic engineering of crops for higher temperatures and drought. There is no assurance that this would be successful. You just can’t develop corn that will grow in the Sahara.
While not the greatest threat, sea level rise will still a big problem, because of the demands adaptation to it will place on resources. We may simply have so many big problems simultaneously that they overwhelm the capacity of civilization to adapt.
Pete Dunkelberg wrote: “We personally (unless some real youngsters are reading this) are not personally the ones who will have to ‘adapt’ to high heat, drought and flood and low resources of all sorts.”
“We personally” are already having to adapt to drought-driven crop failures in the world’s major wheat-exporting nations (Russia, China, Australia) and there is no reason to believe that a comparably devastating drought won’t afflict North America as well, within the lifetimes of even the “real oldsters” reading this blog.
I’m almost sixty. I fully expect to see chronic, world-wide famine settle in, within my lifetime. And perhaps much worse.
Lisa McFadden wrote: “Who even came up with the notion of adaptation or resilient communities in the first place? It’s horridly cynical at best …”
I disagree. Resilient communities, based on locally-generated solar and wind-generated electricity and local sustainable organic agriculture, are the way that human beings will live in the future — if we are to have a future. And of course, they represent not only adaptation but mitigation as well.
Lisa McFadden wrote: “Who even came up with the notion of adaptation or resilient communities in the first place? It’s horridly cynical at best …”
I also disagree with this conclusion. What do we want un-resilient communities? We can either give up or do everything in our power to make sure that the most possible local communities have the best possible chance of surviving the coming collapse. Hope is not cynical. Adapting agriculture to local conditions, building to handle increased heat without air conditioning are just of the few changes we need to make.
jimster@23:
“If we prepare for climate extremes by employing high cost / inefficient technologies immediately and lower cost / more efficient technologies emerge in the near future, we risk a significant economic setback”
History shows that whatever technology is available is used and then when something new comes along, it gradually replaces the the older technology. In fact you actually describe the process quite well!
So why the panic??!
Oh wait a minute, also throughout history there has been resistance to change, with claims that technology would be bad for health, to costly etc.
Meanwhile many decades after it was built the over engineered Forth bridge is still in use, people are still travelling by train despite the initial worries that the speed would make people faint.
And those expensive and inefficient automobiles are now more efficient and cheaper!
See the pattern?
It’s the one you describe and it has been happening since the start of the industrial revolution.
A few people have refered to Dai’s (and by extension Barton’s) predictions about coming drought. These predictions are based on calculations which have shown that many areas having shown an increase in aridity at the same time that rainfall has increased. The predictions are based on a temperature increase resulting in increased evaporation of the increased rainfall. The areas that have supposedly become more arid (based on Dai’s calculations) have not become so. I, for one, am questioning those calculations as they do not correspond to the observed data.
To paraphrase Mark Twain, “News of the death of civilization due to agricultural decline has been greatly exaggerated.”