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Guest commentary from Geert Jan van Oldenborgh and Rein Haarsma, KNMI
Sometimes it helps to take a step back from the everyday pressures of research (falling ill helps). It was in this way we stumbled across Hansen et al (1981) (pdf). In 1981 the first author of this post was in his first year at university and the other just entered the KNMI after finishing his masters. Global warming was not yet an issue at the KNMI where the focus was much more on climate variability, which explains why the article of Hansen et al. was unnoticed at that time by the second author. It turns out to be a very interesting read.
- J. Hansen, D. Johnson, A. Lacis, S. Lebedeff, P. Lee, D. Rind, and G. Russell, "Climate Impact of Increasing Atmospheric Carbon Dioxide", Science, vol. 213, pp. 957-966, 1981. http://dx.doi.org/10.1126/science.213.4511.957
I just came across an interesting way to eliminate the impression of a global warming. A trick used to argue that the global warming had stopped, and the simple recipe is as follows:
The latest incarnation of the CRUTEM land surface temperatures and the HadCRUT global temperatures are out this week. This is the 4th version of these products, which have undergone a number of significant changes over that time and so this is a good opportunity to discuss how and why data products evolve and what that means in the bigger scheme of things.
Richard Lindzen is a very special character in the climate debate – very smart, high profile, and with a solid background in atmospheric dynamics. He has, in times past, raised interesting critiques of the mainstream science. None of them, however, have stood the test of time – but exploring the issues was useful. More recently though, and especially in his more public outings, he spends most of his time misrepresenting the science and is a master at leading people to believe things that are not true without him ever saying them explicitly.
However, in his latest excursion at a briefing at the House of
Lords Commons in the UK, among the standard Lindzen arguments was the following slide (which appears to be a new addition):
What Lindzen is purporting to do is to compare the NASA GISS temperature product from 2012 to the version in 2008 (i.e. the y-axis is the supposedly the difference between what GISS estimated the anomaly to be in 2012 relative to 2008). A rising trend would imply that temperatures in more recent years had been preferentially enhanced in the 2012 product. The claim being made is that NASA GISS has ‘manipulated’ (in a bad way) the data in order to produce an increasing trend of global mean temperature anomalies (to the tune of 0.14ºC/Century compared to the overall trend of 0.8ºC/Century) between the 2008 and 2012 versions of the data, which are apparently shown subtracted from each other in Lindzen’s figure. Apparently, this got ‘a big laugh’ at his presentation.
However, this is not in the least bit true: the data are not what he claims, the interpretation is wrong, and the insinuations are spurious.