Saturday 15 December 2012

No trend in global water vapor, another WUWT fail

Forrest M. Mims III
Forrest Mims is an interesting character. To quote from the introduction to his Science article on amateur science: "Forrest M. Mims III is a writer, teacher, and amateur scientist. He received a Rolex Award for developing a miniature instrument that measures the ozone layer and has contributed projects to “The Amateur Scientist” column in Scientific American. His scientific publications have appeared in Nature and other scholarly journals."

Anthony Watts just published a guest post by Forrest M. Mims III with the title: "Another IPCC AR5 reviewer speaks out: no trend in global water vapor". I have no special expertise in this area, but I am privileged being able to read the article that is discussed. This is sufficient to see that the article and its post are two different worlds. Update: An earlier draft is available (thanks, michael sweet).

First, note that being a "expert reviewer" does not say much. There are over a thousand reviewers, even Anthony Watts himself is an IPCC "expert reviewer". On the other hand, Mims may be an amateur, but did do valued scientific work on UV measurements.

The trend in global water vapor

The post discusses a paper by Vonder Haar et al. (2012) on the NASA Water Vapor Project (NVAP) dataset. The main piece of information missing from the post is that this dataset is only 22 years long. Almost any climatological measurement will not have a statistically significant trend over such a short period, but the story is even weirder.

Just as in the misleading post on homogenization of climate data earlier this year, Anthony Watts again proofs to have a keen eye in finding the best misinformation.

Mims added a list with all the comments of his review. In this list, Watts found this comment:

This paper concludes,

“Therefore, at this time, we can neither prove nor disprove a robust trend in the global water vapor data.”

Non-specialist readers must be made aware of this finding and that it is at odds with some earlier papers.

The complete citation from the Geophysical Research Letters article is:

"The results of Figures 1 and 4 have not been subjected to detailed global or regional trend analyses, which will be a topic for a forthcoming paper. Such analyses must account for the changes in satellite sampling discussed in the auxiliary material. Therefore, at this time, we can neither prove nor disprove a robust trend in the global water vapor data."

In other words, they cannot say anything about the trend, because they have not even tried to compute it and estimate its uncertainty. Especially estimating the error in the trend will be very difficult as the dataset uses different satellites for different periods of the dataset, which invariably creates jumps in the dataset that should not be mistaken for true climate variability or trends.

The paper is thus not at odds with earlier papers. These earlier papers studied longer periods and probably datasets which were more homogenenous and consequently did find a statistically significant trend. There is thus no contradiction.

Sunday 9 December 2012

Changing the political dynamics of greenhouse gas reductions

Photo by Caveman Chuck Coker
, Creative Commons by-nd licence

Another climate conference failed miserably. Maybe we need a completely different system, a system in which forerunners are rewarded and not punished.

A stable, predictable climate is a common good. Climate change is one of the most difficult tragedies of the commons. There are great benefits to using energy and the climate costs are spread almost perfectly to everyone. No single industry or country contributes much to the problem, but some industries and countries do benefit strongly and have a large incentive to halt the negotiations and to spread doubt. This makes greenhouse gas mitigation arguably the most difficult tragedy of the commons.

It is possible to solve such tragedies, the Montreal protocol to curb emissions of chlorofluorocarbons (CFC) to protect the ozone layer seems to work well. The ozone layer is now at its thinnest, but scientists expect that is will start to become thicker soon and return to almost normal levels in several decades. However, in case of the Montreal protocol only the producers of fridges, air conditionings and spray cans were affected. Greenhouse gasses are emitted by the energy, agricultural and building sectors. These are powerful parties and this makes a global treaty difficult. Maybe it is better to solve the tragedy of the commons by allowing countries and regions that want to reduce their CO2 emissions to protect themselves against unfair competition.