On 27 September, the Intergovernmental Panel on Climate Change (IPCC) published its Summary for Policymakers of the contribution to its Fifth Assessment Report by its working group on the physical science basis of climate change.
The IPCC report is likely to prompt many governments to take more action to tackle climate change. It is perhaps no surprise then that climate change 'sceptics' who do not want any limit on the burning of fossil fuels, the main source of greenhouse gas emissions, have been mounting increasingly desperate attacks to try to discredit the IPCC summary and to confuse the public and politicians about its contents.
A key element of the 'sceptic' strategy is to provide articles for the opinion pages of national newspapers to create a distorted account of the IPCC findings. A particularly blatant example of this was provided by The Sunday Telegraph on 29 September which published a vitriolic attack against climate scientists by Lord Lawson of Blaby, the chair of the 'sceptic' lobby group, the Global Warming Policy Foundation.
The article was littered with errors and misrepresentations. Lord Lawson started by wrongly calling the Intergovernmental Panel on Climate Change "a politically motivated pressure group", when, in fact, it is an international body, with 195 governments as members, which commissioned 239 independent researchers at universities and institutes in 39 countries to provide the comprehensive and authoritative assessment of the science of climate change.
He also inaccurately stated that the last IPCC assessment report, published in 2007, was "grotesquely flawed". In fact, the IPCC invited the Inter Academy Council to undertake an independent review of its processes and procedures for producing assessment reports after a small but significant error was found within the four-volume report. While the Council did recommend improvements, Lord Lawson neglected to mention that it also considered that "the IPCC assessment process has been successful overall".
Lord Lawson then went on to criticise the IPCC for including among its authors of reports on methods of reducing greenhouse gas emissions some scientists who work for non-governmental organisations. But he failed to admit that scientists from industry are also included among the authors in order to ensure broad expertise.
Next, he asserted that carbon dioxide is not a pollutant because it is "colourless and odourless", but that is unscientific nonsense. A pollutant is any substance that can cause harmful effects, such as carbon monoxide, another colourless and odourless gas.
Lord Lawson then drew attention to recent trends in global temperature, and ignored the fact that there is good evidence that the recent slowdown in the rate of warming of the Earth's surface may be partly due to an increased amount of heat being absorbed by the deeper oceans, which cover two-thirds of the globe. The IPCC report also points to an equal contribution from an increase in the amount of volcanic particles in the atmosphere, which block out some of the Sun's rays, and a cyclical reduction in solar activity.
Lord Lawson erroneously suggested that "the global warming we can expect by the end of the century is probably less than the IPCC has previously predicted: perhaps some 2.7F (1.5C)". However, in its highest emissions scenario, the IPCC report indicates that global average surface temperature is likely to increase by 3.2 to 5.4 centigrade degrees above its pre-industrial level by the last two decades of this century.
Lord Lawson also falsely alleged that the IPCC report's conclusion that it is 95 per cent probable most of the global warming since 1951 is due to greenhouse gas emissions and deforestation was "plucked from the air" and is "mumbo-jumbo". In fact, it is the considered expert opinion of the scientists after considering all of the evidence and research. Lord Lawson may not like the finding, but then he has no scientific knowledge of his own to draw upon.
Again betraying his lack of scientific understanding, Lord Lawson dismissed the possibility that the addition of large volumes of cold freshwater from the melting of the Arctic land and sea ice could disrupt the circulation of the warm and salty waters of the Gulf Stream. But the IPCC scientists know that they cannot rule it out and pretend that there is no risk.
Lord Lawson's suggestion that human society could simply adapt to any future change in global temperature was particularly reckless and complacent. The IPCC report warns that if greenhouse gas emissions continue to grow throughout this century, there is a significant probability of global warming by more than two centigrade degrees, to a temperature that has not occurred on Earth for about three million years, long before modern humans first appeared.
Lord Lawson also described fossil fuels as "relatively cheap and highly reliable", which will be news to households and businesses whose electricity and gas bills have risen steeply over the last 8 years primarily because the UK is becoming more dependent on expensive imports of natural gas.
Finally, Lord Lawson laughably proposed that developing countries would be better off if the world does not attempt to reduce greenhouse gas emissions. In fact, poor and emerging countries, such as China, understand very well that they would suffer first and foremost from the impacts of unmanaged climate change and, further, that the transition to low-carbon economic growth and development offers additional benefits of lower local pollution, greater energy security and more efficient homes and businesses.
Not to beat about the bush, it was morally outrageous for Lord Lawson, with no scientific expertise, to dismiss the huge risks of climate change and to insist that he is a more reliable source of information than the IPCC.
Bob Ward is policy and communications director at the Grantham Research Institute on Climate Change and the Environment at London School of Economics and Political Science.