At a recent meeting someone thrust a small booklet into my hand. Entitled “Reconsidering the Climate Change Act”, it summarised a presentation given on Feb 22nd this year in the House of Commons by the renowned atmospheric physicist Richard S. Lindzen of MIT. And it should be compulsory reading for policymakers, including that huge majority of MPs who voted for the Climate Change Act in October 2008 (as an exceptionally early snow fell over London). The booklet is published by the Campaign to Repeal the Climate Change Act. For a copy, e-mail firstname.lastname@example.org.
The Climate Change Act is expected to cost the British economy an eye-watering £18 billion a year for forty years. And it’s probably unnecessary.
Lindzen makes some key points. The warming we have seen over the last century is less than 1 degree C, which is entirely consistent with natural variation. It is best interpreted as a continuing recovery from the Little Ice Age, preceding a new 21st Century Optimum comparable to the Roman Optimum or the Mediaeval Warm Period. And in fact it seems to have stopped in 1998: there has been no further warming trend for the past fifteen years.
The Arctic Ice is not melting significantly (though reports of its demise have appeared in the press a number of times since the mid-nineteenth century). And long-term changes in sea level are almost within the limits of measurement error, and are utterly trivial compared either to shorter-term sea level changes or the very real and rapid changes at the beginning of the current interglacial.
Anyone who has looked at a graph of global temperatures over the last two and a half million years would see an Ice Age, with short regular spikes to warmer temperatures every 100,000 years or so. We are in such a spike right now, and if that very regular cycle continues, we could expect glaciation to resume in the next thousand years or so. Global cooling is a much more realistic threat to humanity than global warming. A resumption of the glaciation seen 20,000 years ago would decimate humanity. Snowball Earth could be with us soon.
Lindzen points out that a doubling of atmospheric CO2, from the current c. 400 ppm to 800 ppm would probably cause a warming of around 1 degree C. And because the relationship is logarithmic, it would take a further doubling — an extra 800 ppm, not an extra 400 — to raise it another one degree. The rather arbitrary target of “Not more than Two degrees” seems unlikely to be exceeded.
So how come the IPCC is pedalling disaster scenarios? They have to postulate positive feedback effects to amplify the warming and increase the sensitivity of temperature to CO2. Yet these effects have not been demonstrated, still less proved. Meantime studies of the actual relationship between temperature and warming over the last century suggest that sensitivity is actually lower than one degree per doubling — that is, there may actually be negative feedbacks, like increased cloud cover affecting the albedo (reflectivity) of the earth.
The IPCC’s disaster scenario is quite literally speculative, and unsupported by the evidence. It exists in a virtual world of computer models which reflect the prejudices and the inputs of the climatologists who programmed them, and have about as much relevance to the real world as Grand Theft Auto.
The commentariat ridicules Lembit Opik for his obsession with the threat of an asteroid strike, yet they fail to see that their obsession with climate change is equally over-cooked. The Climate Change Act is a catastrophically disproportionate response to an entirely speculative problem.
Climate Change is a threat to humanity first and foremost because of the vast economic damage which our responses to it will do.