Archives for 2010

Gilbert Plass was one of the pioneers of the calculation of how solar and infrared radiation affects climate and climate change. In 1956 he published a series of papers on radiative transfer and the role of CO2, including a relatively ‘pop’ piece in American Scientist. This has just been reprinted (as an abridged version) along with commentaries from James Fleming, a historian of science, and me. Some of the intriguing things about this article are that Plass (writing in 1956 remember) estimates that a doubling of CO2 would cause the planet to warm 3.6ºC, that CO2 levels would rise 30% over the 20th Century and it would warm by about 1ºC over the same period. The relevant numbers from the IPCC AR4 are a climate sensitivity of 2 to 4.5ºC, a CO2 rise of 37% since the pre-industrial and a 1900-2000 trend of around 0.7ºC. He makes a lot of other predictions (about the decrease in CO2 during ice ages, the limits of nuclear power and the like), but it’s worth examining his apparent prescience on these three quantitative issues. Was he prophetic, or lucky, or both?
[Read more…] about The carbon dioxide theory of Gilbert Plass

Continuation of the open thread. Please use these threads to bring up things that are creating ‘buzz’ rather than having news items get buried in comment threads on more specific topics. We’ll promote the best responses to the head post.

Knorr (2009): Case in point, Knorr (GRL, 2009) is a study about how much of the human emissions are staying the atmosphere (around 40%) and whether that is detectably changing over time. It does not undermine the fact that CO2 is rising. The confusion in the denialosphere is based on a misunderstanding between ‘airborne fraction of CO2 emissions’ (not changing very much) and ‘CO2 fraction in the air’ (changing very rapidly), led in no small part by a misleading headline (subsequently fixed) on the ScienceDaily news item Update: MT/AH point out the headline came from an AGU press release (Sigh…). SkepticalScience has a good discussion of the details including some other recent work by Le Quéré and colleagues.

Update: Some comments on the John Coleman/KUSI/Joe D’Aleo/E. M. Smith accusations about the temperature records. Their claim is apparently that coastal station absolute temperatures are being used to estimate the current absolute temperatures in mountain regions and that the anomalies there are warm because the coast is warmer than the mountain. This is simply wrong. What is actually done is that temperature anomalies are calculated locally from local baselines, and these anomalies can be interpolated over quite large distances. This is perfectly fine and checkable by looking at the pairwise correlations at the monthly stations between different stations (London-Paris or New York-Cleveland or LA-San Francisco). The second thread in their ‘accusation’ is that the agencies are deleting records, but this just underscores their lack of understanding of where the GHCN data set actually comes from. This is thoroughly discussed in Peterson and Vose (1997) which indicates where the data came from and which data streams give real time updates. The principle one is the CLIMAT updates of monthly mean temperature via the WMO network of reports. These are distributed by the Nat. Met. Services who have decided which stations they choose to produce monthly mean data for (and how it is calculated) and is absolutely nothing to do with NCDC or NASA.

Further Update: NCDC has a good description of their procedures now available, and Zeke Hausfather has a very good explanation of the real issues on the Yale Forum.