19 March 2012

Rewriting the Academic Literature

 

[UPDATE: Jeff Masters graciously responded to my email invitation to comment with this reply just received by email:
Hi Roger, thanks for the note. As you point out, my discussion of Bouwer's excellent paper was too short and potentially misleading. When I discuss his paper in the future, I will include the sentence,

"Studies that did find increases after normalization did not fully correct for wealth and population increases, or they identified other sources of exposure increases or vulnerability changes or changing environmental conditions. No study identified changes in extreme weather due to anthropogenic climate change as the main driver for any remaining trend."
 Thanks Jeff!]

Writing in the popular meteorology magazine Weatherwise on disasters and climate change, Jeff Masters of the Weather Underground has decided to rewrite what the academic literature says to be more favorable to what he would like it to have said.

Masters (mis)characterizes a 2011 literature review by Laurens Bouwer as follows:
A 2010 paper in the Bulletin of the American Meteorological Society by Netherlands researcher Laurens Bouwer titled, “Have Disaster Losses Increased Due to Anthropogenic Climate Change?”, looked at 22 disaster-loss studies worldwide, published between 2001 and 2010 All of the studies showed an increase in damages from weather-related disasters in recent decades. Fourteen of the 22 studies concluded that there were no trends in damage after correcting for increases in wealth and population, while eight of the studies did find upward trends even after such corrections, implying that climate change could be responsible for the increased disaster losses.
Does Bouwer conclude that eight of those studies actually "[imply] that climate change could be responsible for the increased disaster losses"?  Actually, no. Bouwer concludes exactly the opposite to what Masters attributes to his paper.

And here is what Bouwer actually says (here in PDF):
Studies that did find increases after normalization did not fully correct for wealth and population increases, or they identified other sources of exposure increases or vulnerability changes or changing environmental conditions. No study identified changes in extreme weather due to anthropogenic climate change as the main driver for any remaining trend.
 Here is what Bouwer concludes on the full set of 22 papers that he reviewed :
The studies show no trends in losses, corrected for changes (increases) in population and capital at risk, that could be attributed to anthropogenic climate change. Therefore, it can be concluded that anthropogenic climate change so far has not had a significant impact on losses from natural disasters.
It is of course perfectly acceptable for people to challenge data and analyses on the possible relationship of human-caused climate change and disaster losses, and ideally they will do so in the academic literature. But when existing peer-reviewed studies are fundamentally misrepresented in popular discussions, no one's interests are served.

7 comments:

Roddy said...

Roger, a hesitant pedant here, venturing into disaster loss / extreme weather territory. But you only learn by sticking your neck out.

Masters didn't say that Bouwer said '... implying that climate change could be responsible'. Masters said that according to Bouwer 2010, 8 out of 22 studies found trends after correcting for wealth and population, which is correct, and Masters said that this implies '.... that climate change could be responsible'. Which is certainly a potential implication, and indeed the question in the title of Bouwer's paper.

So while Bouwer found that incorrect normalisation or 'false' (variability) trends or other specific reasons explain these 8 studies, which Masters omitted to say, he did immediately go on with:

'In all 22 studies, increases in wealth and population were the “most important drivers for growing disaster losses.” Thus, it is still controversial whether or not climate change is increasing disaster losses. There is too much year-to-year variability in the weather and disasters to tell. Extreme events, by their nature, are rare, making it tough to study them.' Which isn't terrible, although you'd dispute controversial.

Fundamental misrep?

His summary on tornadoes:

'In summary, there is not enough evidence to judge whether or not climate change is affecting severe thunderstorms and tornadoes in the United States. Recent research indicates the possibility that the future climate may see an increase in severe thunderstorms, but much more work needs to be done. Until we have better evidence to the contrary, the extraordinary tornado season of 2011 will have to be regarded as a natural atmospheric freak occurrence.'

Roger Pielke, Jr. said...

-1-Roddy

Thanks, but this statement of yours is not correct:

"Masters said that according to Bouwer 2010, 8 out of 22 studies found trends after correcting for wealth and population, which is correct"

Not all of the studies corrected for both wealth and population (which is what Bouwer means by "did not fully correct for wealth and population increases")

Also, 2 of the 8 cited found no trends over the full record, but trends in a shortened subset, and properly conclude that there is no evidence for overall trends.

Of the other 6, all are incomplete normalizations.

Thanks!

Roddy said...

I knew this was risky. *sticks neck out again*

Bouwer: 'The general approach taken in these studies is to correct or normalize (Pielke and Landsea 1998) the original economic losses for inflation and changes in exposure and vulnerability that are related to growth in population and wealth.'

and indeed 20 of the 22 attempted a normalisation along these lines? - adjusting for changes in exposure related to growth in p&w ?

'Most of the 22 studies have not found a trend in disaster losses, after normalization for changes in population and wealth (Table 1). However, eight studies have identified increases:'

ok, I see Masters replaces the careful and more general 'increases' with 'upward trends', I wasn't savvy enough to spot that.

Thanks.

Roger Pielke, Jr. said...

-3-Roddy

Yes, the details matter ... However, rather than mis-parse Bouwers, Masters could have just cited the recent IPCC SREX report.

Laurens said...

Well, is the SREX really less ambiguous?

"Long-term trends in disaster losses adjusted for wealth and population increases have not been attributed to climate change, but a role for climate change has not been excluded (high agreement, medium evidence)"

See: http://www.ipcc-wg2.gov/SREX/images/uploads/SREX-SPM_FINAL.pdf

Roger Pielke, Jr. said...

-5-Laurens

Thanks ... certainly more ambiguous that the initial draft language ;-)

Kip Hansen said...

Thank you, Roger, for correcting Jeff Masters misleading misrepresentation on disaster damages and climate change.

All too often these somewhat subtle (but, at the same time, huge...) misrepresentations are allowed to slide.

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