Why academic researchers should scrutinise the lobbying of climate change ‘sceptics’

A recent exchange of letters has revealed the tactics which so-called climate change ‘sceptics’ from the Global Warming Policy Foundation are using to lobby the UK Government in a bid to stop policies to tackle global warming.

In August 2011, Lord Lawson of Blaby and Lord Turnbull of Enfield, respectively former Chancellor of the Exchequer and former Cabinet Secretary, wrote to the Secretary of State for Energy and Climate Change, Chris Huhne, enclosing a copy of an essay by Lord Turnbull which had been published by the Foundation.

The pamphlet, called ‘The really inconvenient truth or it ain’t necessarily so‘, is riddled with errors of fact about climate change science and policies. Indeed the opening sentence of the Summary claims wrongly that the Climate Change Act commits the UK to “reduce man-made emissions of CO2 by 80 percent from 1990 levels by 2050”, when in fact the legislative target applies to all greenhouse gases, not carbon dioxide alone.

Mr Huhne sent a robust response to Lords Turnbull and Lawson on 18 November, indicating that they were “misinformed” and that their conclusions were “poorly supported by the underlying science evidence”.

Unabashed, the two Lords wrote back to the Secretary of State on 25 November. Their letter, like the pamphlet, contained many misleading and inaccurate statements.

At this point, I thought it would be helpful to provide the Secretary of State with a view from the academic research community. This is what I wrote:

Dear Secretary of State,

 

I am writing to alert you to several significantly misleading and inaccurate statements about the science of climate change that were contained in the letter that was sent to you on 25 November by Lord Turnbull and Lord Lawson from the Global Warming Policy Foundation.

 

It has been common practice for the Foundation to attempt to justify its campaign against the UK’s climate change and energy policies by seeking to undermine the research findings of climate scientists. However, I believe it is important to promote informed public debate about policies by exposing the flaws in the rhetorical arguments put forward by such lobby groups.

 

First, the opening paragraphs of the letter from Lords Turnbull and Lawson disputes the evidence for human influence on the climate, but ignores the following multiple lines of evidence, as recently outlined by a special panel of the National Research Council of the United States National Academies (‘Advancing the Science of Climate Change‘, published in 2010):

 

  • Earth’s surface temperature has clearly risen over the past 100 years, at the same time that human activities have resulted in sharp increases in atmospheric levels of carbon dioxide and other greenhouse gases;
  • both the basic physics of the greenhouse effect and more detailed calculations in atmospheric greenhouse gases should lead to warming of the Earth’s surface and lower atmosphere;
  • the vertical pattern of observed warming – with warming in the bottom-most layer of the atmosphere and cooling immediately above – is consistent with warming caused by greenhouse gas increases and is inconsistent with other possible causes; and
  • detailed simulations with state-of-the-art computer based models of the climate system are only able to reproduce the observed warming trend and patterns when greenhouse gas emissions from human activities are included.

 

Second, Lords Turnbull and Lawson claim that there is “a growing realisation among scientists” that other influences on climate may be more significant than greenhouse gas emissions from human activities, but they neglect to address the following points:

 

  • the climate system varies naturally on a wide range of timescales, but a rigorous statistical evaluation of observed climate trend, supported by analyses with climate models, indicates that the observed warming, particularly since the late 1970s, cannot be attributed to natural variations;
  • satellite measurements conclusively show that solar output has not increased over the past 30 years, so an increase in energy from the Sun cannot be responsible for recent warming; and
  • direct measurements show that the number of cosmic rays, which some scientists have suggested might influence cloud formation and hence climate, have neither declined nor increased during the last 30 years.

 

The report by the National Research Council panel pointed out that “an overwhelming majority of climate scientists” agree that “much of the observed warming since the start of the 20th century, and most of the warming over the last several decades, can be attributed to human activities”. This is in line with the assessment of the UK’s Royal Society which last year concluded: “There is strong evidence that changes in greenhouse gas concentrations due to human activity are the dominant cause of the global warming that has taken place over the last half century”. Indeed, there is not a single credible scientific organisation in the world that currently claims human activities are not the major cause of recent global warming.

 

Third, the letter from Lords Turnbull and Lawson alleges that “there has been no warming trend in the last 10 years”. However, they apparently fail to recognise that an analysis of each of the 32 sequences of 10 consecutive years of global annual temperatures that occurred between 1970 and 2010 shows that only 7 define statistically significant (at the 95 per cent level) warming trends, even though the trend over the entire 41 year period is clearly upwards and statistically significant. Hence, the Lords apparently do not understand that measuring trends from just 10 data points carries the serious risk of failing to detect statistically significant signals amid the noise.

 

Fourth, the Lords suggest the published research shows that even on a ‘business as usual’ pathway for global emissions over the next 100 years, the amount of warming will only be “moderate”, and they complain that there is “no convincing evidence” that equilibrium climate sensitivity could be as much as 3°C. However they are apparently unaware of the many scientific papers on this topic which were reviewed by the Intergovernmental Panel on Climate Change in its Fourth Assessment Report  in 2007. The IPCC concluded that the equilibrium climate sensitivity is “likely to be in the range 2°C to 4.5°C with a best estimate of about 3°C, and is very unlikely to be less than 1.5°C”. This conclusion was based on a wide range of studies drawing on several sources of information, including:

 

  • use of coupled atmosphere-ocean general circulation models;
  • examination of the transient evolution of temperature over the past 150 years;
  • examination of the rapid response of the global climate system to changes in forcing caused by volcanic eruptions;
  • palaeoclimate studies such as reconstructions of the Northern Hemisphere temperature record of the past millennium and the Last Glacial Maximum; and
  • assessment of present climate against large ensembles of climate model simulations.It is, therefore, simply not true that there is “no convincing evidence” for a climate sensitivity of 3°C.Finally, Lords Turnbull and Lawson go on to claim that a paper by Andreas Schmittner and co-authors, published by the journal ‘Science’ on 24 November 2011, “corroborates a low estimate of climate sensitivity”. In fact, the study suggests that climate sensitivity lies within the range of 1.4 and 2.8°C, with a 90 per cent cumulative probability. This estimate was based on a palaeoclimate reconstruction of the Last Glacial Maximum, using proxies such as pollen, and a range of model simulations employing different estimates of climate sensitivity. As the accompanying commentary  by Gabriele Hegerl and Thomas Russon pointed out, this new study is an interesting addition to the literature, but it hardly supersedes all other previous studies that draw on many different sources of information.

 

In short, the letter from Lords Turnbull and Lawson contains numerous inaccurate and misleading claims about the science of climate change. It would be exceedingly unwise to base any climate policies on such a flawed account of the scientific evidence. I hope that all members of the Coalition Government, despite the lobbying by the Global Warming Policy Foundation, will continue to apply a robust and rigorous evidence-based approach to policy-making on climate change, and will draw upon the best available scientific research and analysis rather than the propaganda of campaign groups.
It is clear that the campaign groups, such as the Global Warming Policy Foundation, are lobbying the Government to abandon its climate change policies. In making their case, these climate change ‘sceptic’ groups frequently cite the work of academic researchers. To protect the public interest and promote the integrity of the policy-making process in such circumstances, it is important for researchers to remain vigilant about how their work is being used, and to be proactive in identifying and correcting erroneous portrayals of their findings.

 

Bob Ward is policy and communications director of the Grantham Research Institute on Climate Change and the Environmentat the London School of Economics and Political Science (LSE)