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Carbon Brief Staff

Carbon Brief Staff

27.03.2011 | 12:00am
ScienceLetters from UK Government’s Chief Scientific Advisor reveal critical view of Lord Lawson’s climate arguments
SCIENCE | March 27. 2011. 0:00
Letters from UK Government’s Chief Scientific Advisor reveal critical view of Lord Lawson’s climate arguments

On the 31st March 2010, the House of Commons Science and Technology Committee heard evidence for an enquiry into the University of East Anglia’s Climatic Research Unit’s E-mails. Present to give evidence were Lord Nigel Lawson, founder of climate sceptic think-tank the Global Warming Policy Foundation, and Sir John Beddington, the government’s Chief Scientific Advisor.

In the same month, Lord Lawson asked John Beddington to review his bestselling book about climate change: ‘ An Appeal to Reason, A Cool Look at Global Warming‘. Beddington obliged, sparking an exchange of official letters between the two over the coming months – released to Spinwatch under freedom of information legislation and seen by Carbon Brief.

The tone of the letters is polite, and Beddington’s criticisms are restricted to the scientific statements Lord Lawson makes in his book.

On some issues – the importance of improved water management for example, he makes clear his agreement with Lord Lawson. However, his assessment of the material in the book which discusses climate science raises serious questions about the validity of the arguments Lawson makes, and his interpretation of scientific material.

The full letters cover twenty separate points. To pick one example of the material covered – when addressing the argument often repeated by Lord Lawson (and more recently by the GWPF – for example here) that “There has been no global warming since the turn of the century”, Beddington writes:

“â?¦short-term temperature trends are meaningless in the context of global warmingâ?¦ In order to see the effects of greenhouse gases, it is necessary to examine the long-term trend, which has clearly been upward (global average temperatures are now about 0.75°C warmer than they were 100 years ago, and the last decade has been the hottest since records began).”

In his letter in May 2010, Lord Lawson responds

“The essence of your point seems to be the assumption that, while the temperature record over 20 years (from 1980 to 2000) is immensely significant, the temperature record over 10 years (the first decade of the 21st century) is of no significance at all. I know of no scientific basis for this seemingly arbitrary distinction.”

Beddington then writes back

“your representation of my argument does not accurately reflect what I wrote. The point I was making is that in order to assess the impact of greenhouse gases on global temperature, it is necessary to consider the long-term (multi-decadal) trendâ?¦. When we consider the record decade by decadeâ?¦it is clear that even allowing for uncertainties in the observations, that last three decades have each been significantly warmer than the previous one ie the error bars do not overlap.”

Lord Lawson also argues in the first chapter of his book that global warming has stopped in this century, with global average temperature higher in 1998 than during any year between 2001 and 2007. Beddington writes

“It is meaningless to compare global average temperature in any two years within a period of a decade or two, because natural climate variability can cause temperatures to fluctuate â?¦ 1998 was an unusually warm year, largely due to a natural climate phenomenon known as an El Niño event.”

Lord Lawson also appears to have misunderstand the nature of key climate feedback processes, writing

I have become increasingly puzzled by the proposition that warming brings about more water vapour, which in turn causes more warming, which then presumably produces more water vapour, and so on ad infinitum. This implies a runaway instability which, if true, would have made the planet uninhabitable long ago.

Beddington replies

The existence of a feedback in the climate (or any other) system does not imply a runaway feedback â?¦ the way in which the planet achieves energy balance is more complex than your simple argument for a runaway instability.

The table below summarises the points covered in the letter, which cover most of the scientific arguments made in An Appeal to Reason.

The scientific material in An Appeal to Reason is based on many of the most common climate sceptic arguments. Many of the arguments in the book have subsequently been repeated by Lord Lawson’s think tank The Global Warming Policy Foundation. The GWPF state in their founding document: “The Object of the Charity is to advance the public understanding of global warming and of its possible consequences.”

Beddington’s is a Professor of Applied Population Biology. He was appointed as Government Chief Scientific Advisor in January 2008. In the letters and supporting documents, he refers to the wider body of scientific work and peer-reviewed literature to correct the claims made by Lawson.

Beddington recently wrote in a blog for the New Scientist entitled ‘We need both scepticism and consensus’:

It is time the scientific community became proactive in challenging misuse of scientific evidence. We must make evidence, and associated uncertainties, accessible and explicable. In a world of global communication, we cannot afford to only speak to ourselves. We must also be confident in challenging the misrepresentation or exaggeration of evidence and the conclusions it leads to. Where significant consensus exists, it must be made obvious.

The letters obtained under FOI can be downloaded here.

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