Saturday, September 14, 2013

So Much for Accuracy

Oops....
Oops, so much for accuracy...
Bjorn Lomborg's op-ed in the Washington Post writes "Gavin Smith"....

And, indeed, scientists don't attribute every extreme event to climate change -- see the recent report "Explaining Extreme Events of 2012 from a Climate Perspective" in BAMS. And when/if they do, it's only in retrospect after some careful study....

But some people are always going to find it useful to (unjustifiably) allude otherwise....

Added: Even Climate Central goes there with the floods in Boulder:
It will take climate scientists many months to complete studies into whether manmade global warming made the Boulder flood more likely to occur, but the amount by which this event has exceeded past events suggests that manmade warming may have played some role by making the event worse than it would have otherwise been.
Is it really so tough to wait for the studies.... The BAMS report found no causative influence of climate change on last year's midwest drougth, except to the extent higher temperatures increased evaporation rates from reservoirs and soils:
"The implication is that human alteration of the atmospheric composition may have had little effect on the frequency of low-precipitation periods. This leads us to hypothesize that if there are consequential changes to the hydrological cycle driving extreme dryness at seasonal scales, they will not be to rates of input, but to rates of output, via evaporative demand with increased surface warming. However, a recent GCM-based study using improved land surface representation suggests the effects of warming on drought in the central United States will be modest (Hoerling et al. 2012a)."
These causations, or lack of them, are not obvious; it's not too much to ask that an outlet like Climate Centeral, purportedly devoted to accurate reporting of climate change, wait for the scientific studies to appear.

5 comments:

Jon said...

That's an awful lot of dudgeon over Climate Central saying the recent events may have been made worse by manmade warming but we'll have to wait months for scientists to study the question properly. As far as I can tell, you don't actually disagree with that. If you looked and this was the least defensible statement regarding the Boulder flooding you encountered from anyone on the consensus side of the debate over climate change, then apparently the consensus side is doing a pretty good job of refraining from making any definite claims that aren't supported by the evidence.

David Appell said...

Actually, I didn't go looking for those attruting the Boulder floods to climate change, except for Bill McKibben. I came across Climate Central's article afterward.... It won't matter much if they backtrack now -- they have already put the bug in people's ear, unjustifiably. What's wrong with simply reporting the truth -- that no one (yet) knows if this flood was assisted by climate change?

Mike H said...

The issue of attribution is hotly contested. Here for example.

"The answer to the oft-asked question of whether an event is caused by climate change is that it is the wrong question. All weather events are affected by climate change because the environment in which they occur is warmer and moister than it used to be….

The air is on average warmer and moister than it was prior to about 1970 and in turn has likely led to a 5–10 % effect on precipitation and storms that is greatly amplified in extremes. The warm moist air is readily advected onto land and caught up in weather systems as part of the hydrological cycle, where it contributes to more intense precipitation events that are widely observed to be occurring."

Kevin E. Trenberth, senior scientist, National Center for Atmospheric Research
http://link.springer.com/article/10.1007%2Fs10584-012-0441-5

And here on the BAMS report and the difficulty of attributing specific precipitation events.
http://theconversation.com/the-blame-for-rain-is-mainly-done-in-vain-17896

On drought here
http://theconversation.com/global-drought-has-not-increased-but-climate-change-is-still-a-threat-10751

vs here
http://www.skepticalscience.com/Dai_et_al_2010.html

Jon said...

David Appell - ...no one (yet) knows if this flood was assisted by climate change?

Climate Central - It will take climate scientists many months to complete studies into whether manmade global warming made the Boulder flood more likely to occur, but the amount by which this event has exceeded past events suggests that manmade warming may have played some role by making the event worse than it would have otherwise been.

To me, these are not contradictory statements. Differences - CC is more verbose and is willing to hint at what they think is likely to be the conclusion of future attribution studies for this event. Obviously, you feel that it should be verboten to say how you think a scientific investigation is likely to conclude but I really can't see why. A thought experiment - would you have been similarly critical of a scientific journalist in January 1919 who was willing to say he thought it likely that observational evidence would accord with general relativity but that people ought to wait for Eddington's expedition to come back with their measurements before claiming the theory was confirmed?

David Appell said...

Jon: Yes, I do realize that Climate Central *tried* to be good. But they just couldn't resist discussion of a link between this event and climate change. They simply couldn't write something like, "Scientists will be analyzing this event in the coming months to determine its relation to manmade climate change, if any."

I think it matters, because the recent report in BAMS found no link between last year's midwestern droughts and climate change:
http://journals.ametsoc.org/doi/abs/10.1175/BAMS-D-12-00021.1

except to the extent that higher temperatures increased evaporation and hence reduced water supplies in reservoir and in soil. That's not an insignificant connection, but it's also not a cause-and-effect relationship. And I suspect many have been left with the cause-and-effect insinuation as one of the takeaway messages from last year's drought. I suspect I could find such linkages on the Climate Progress blog if I looked.