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An Important Report on Climate and Extreme Events

by Michael Levi
November 18, 2011

The IPCC has issued a special report on “Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation” (SREX). It’s an immensely useful document. Those of us whose research focuses on policy responses to climate change are bombarded daily with new studies that claim to have established that this or that cataclysmic outcome (devastating drought, mass species extinction, hurricanes galore) is a virtual certainty. But I’ve picked through too much bad climate-related work, including in top journals like Science and Nature, to simply accept every peer reviewed paper on faith. Indeed while these studies are often compelling, it’s difficult to separate those that are genuinely solid from ones that rest on less stable ground. That’s why institutions like the IPCC, and reports like this new one, are so valuable.

I take three big messages from from the study. The first is that there are a host of extreme events – particularly much larger numbers of unusually hot days and heat waves – that are virtually guaranteed given current emissions trends. The second is that there are a bunch of other worries – including, most prominently in the report, more intense cyclones – that are quite likely to materialize. The third, though, is that for many of the risks that people often talk about, ranging from greater drought to increased odds of big floods, there remains enormous disagreement that isn’t reflected by some of the more breathless reports about recent scientific work. I don’t want to suggest that this is reason for avoiding action on climate change – fifty-fifty odds of widespread drought is plenty bad for me. Nonetheless, the nuanced parsing of the literature is helpful.

I’d be remiss if I didn’t flag a handful of problems with the study, in part because I think there are some lessons to be learned for future IPCC reports. The SREX exercise was aimed at assisting with adaptation planning. It thus models a wide range of emissions scenarios, one of which is far more benign than anything one might expect given current policy. As a result, some of the conclusions in the report are muddied, since it’s sometimes impossible to tell whether a particular outcome is uncertain because of limited climate knowledge or because the outcome will depend on the emissions path. In many cases, the report elaborates on distinctions between the emissions cases, but it does not do that consistently enough.

The study executive summary is also being released several months before the actual study, which won’t be out until February. Flaws in past IPCC summaries have typically been brushed aside with allusions to the more sophisticated full reports. But the IPCC knows that it’s the first release – in this case the executive summary – that will get all the attention. They should have waited until they could release the whole thing before they went public. Relatedly, the study seems to have been rushed into print so quickly that figure and table captions are in different parts of the document from the figures and tables themselves. That’s a fine format for journal subsmissions, but it makes the study absurdly difficult to read. Some of the travails of the IPCC over the past few years have clearly taught its leaders lessons about how to approach uncertainty, particularly in its summary documents. But they still have some way to go in polishing the operation.

Post a Comment 5 Comments

  • Posted by Jackie

    I disagree with your statement that the IPCC should have waited to release the executive summary until the entire document was released. This is more than just about policy. Rather, it is about saving lives and increasing public awareness that this is not a drill. Lives are now forever being changed and our children will face the worst of it. The situation is an infinite downward spiral which increases with time.

    But as Grocho Marx said “I don’t care about future generations. After all, what have they ever done for me?” And, that seems to be the way it is with most economists, fossil fuel interests, and denialists.

    I work for an environmental firm which has fossil fuel clients. In one sentence they will speak about how as a coal company met its greenhouse gas inventory goal, and the next how they plan to blow up the next mountaintop to remove coal.

    This is the type of disconnect that keeps me up at night, along with that pesty NOAA weather radio that keeps going off because of all these extreme weather events.

    So, it is my hope that the early release of the executive summary makes a light bulb go off in some mother’s head. Perhaps she will realize that she needs to start taking precautions including buying a NOAA weather radio. (Available most electronic stores for about $20 and they make great gifts.) Then she too can have as many sleepless nights as I.

  • Posted by David B. Benson

    Important? Only if it causes enough people to recognize that likely their weathr is going to (continue to) deteriorate.

  • Posted by Mr. Richards

    Well, its people discretion whether to take this events as important report to Climate and Extreme Events. Well for me,I find it important.

  • Posted by Lubomir Mitev

    If you want another report, based on the IPCC one, you can take a look at the Flemish Ministry of Environment, who recently released a local study for Belgium. The main conclusions are that:

    The annual average temperature in Belgium shows continuous increase since the early 19th Century. The average temperature is 2.3 degrees Celsius higher than that in 1830.
    The warmest years in the period analyzed are situated between 1989 and 2000.
    The major increases in temperature have occurred during the Spring and Summer seasons.
    Rainfall has increased an average of 5 mm per decade, with more precipitation observed in Winter and less in Summer.
    Average sea-level has risen on the Belgian coast by 103mm-133mm compared to 1970.

    If you want the graphs they produced, you can check them out at:

  • Posted by Danley Wolfe

    The Durban meetings if anything should hopefully provide a sounder framework and strategy than taken by the U.N./IPCC and climate consensus in the past. Sounder basis for premise -> date -> premise -> conclusions. More and more scientific community and general public if not the politicians will no longer access Kuhnian paradigm shift consensus voting as a basis for spending trillions of dollars and the days of easy money are also over. If not falsifiability a stronger framework based on scientific significance of hypothess testing is needed before saying it a drawn conclusion and even a done deal. The current uncertainty in attribution is much larger than acknowledged and projections of long term doubling / climate sensitivity are lower than IPCC has claimed in the past (for example Schmittner et al, in recent issue of Science find 2 deg versus IPCC 4-6 deg).

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