Further glimpses emerged yesterday evening of the parallel universe that climate change ‘sceptics’ are attempting to create in order to further their cause.

In their alternative world, the laws of atmospheric physics do not apply and increasing emissions of greenhouse gases pose no threat to future prosperity and well-being.

At a debate organised by ‘Christians in Parliament’, Lord Lawson of Blaby, who is the ‘intelligent designer’ of this other universe, provided a masterclass in how to avoid an inconvenient dependence on evidence and reasoning when faced with the risks of climate change.

He started by claiming that most climate scientists now agree that the sensitivity of the climate to changes in atmospheric concentrations of greenhouse gases is low. The only trouble is that the Intergovernmental Panel on Climate Change (IPCC), the world’s most authoritative source of information on the subject, does not agree with him.

On 2 November, the IPCC published the Synthesis of its Fifth Assessment Report, concluding that the value of the long-term rise in global mean surface temperature in response to a doubling of atmospheric concentrations of carbon dioxide is likely to lie between 1.5 and 4.5 centigrade degrees.

This means that, in the real world, the global average temperature could be 5 centigrade degrees or more above its pre-industrial level by the end of this century, if annual global emissions of greenhouse gases continue to increase at the current rate.

However, Lord Lawson chose only to accept the low end of the range cited by the IPCC, warming that the report should not be considered “the last word” and instead should be treated as a scientific smorgasbord from which it is possible to pick and choose which facts to accept.

He argued that global temperature would therefore only rise by 2.5 degrees this century compared with pre-industrial, and went on to cite estimates by the IPCC that this would cause damage equivalent to between 0.2 and 2.0 per cent of global GDP.

Significantly, he neglected to mention that the IPCC is very cautious about the credibility of these figures, noting: “These impact estimates are incomplete and depend on a large number of assumptions, many of which are disputable. Many estimates do not account for the possibility of large-scale singular events and irreversibility, tipping points, and other important factors, especially those that are difficult to monetize, such as loss of biodiversity.”

Similarly, Lord Lawson told the audience that there was no evidence of any changes in extreme weather. But in the real world, the IPCC report found: “Changes in many extreme weather and climate events have been observed since about 1950. Some of these changes have been linked to human influences, including a decrease in cold temperature extremes, an increase in warm temperature extremes, an increase in extreme high sea levels and an increase in the number of heavy precipitation events in a number of regions.”

Having declared that climate change could only lead to small risks in his parallel universe, Lord Lawson called for people and ecosystems to simply adapt to future impacts. He predicted that future generations would anyway be much richer than people are today by assuming that economic growth in his alternative world will continue largely unaffected by any impacts of climate change.

However, recent research has shown that climate change can undermine the drivers of economic growth and that unabated emissions could lead to a collapse on living standards.

From the audience, I asked Lord Lawson if he accepted or rejected the following conclusion about the real world from the new IPCC report:

“Without additional mitigation efforts beyond those in place today, and even with adaptation, warming by the end of the 21st century will lead to high to very high risk of severe, widespread, and irreversible impacts globally.”

Lord Lawson remained silent.

But the construction of the parallel universe in which atmospheric physics does not apply allows Lord Lawson to justify his main objection to climate change policies. He is implacably opposed to the UK limiting its consumption of fossil fuels.

He attacked the Climate Change Act, which he wrongly attributed to Ed Miliband. In fact, the Bill was introduced into Parliament almost 12 months before Miliband became Secretary of State for Energy and Climate Change, and was passed in 2008 with overwhelming cross-Party support, as only five Conservative MPs voted against it.

Lord Lawson declared that the UK is acting alone against climate change, and that countries such as India and China are not doing anything to switch away from fossil fuels. This also is not true, as China is already starting to abandon coal for cleaner sources of energy, and new Indian Prime Minister Modi has promised to bring electric lighting to 400 million people without power by 2019 through the installation of solar panels.

And predictably, he complained about wind farms, labelling them the biggest threat to birds in the UK. Many in the audience laughed at this obvious exaggeration. Cats kill more birds each year than wind turbines.

Lord Lawson has enjoyed extraordinary success in rallying climate change ‘sceptics’ since he set up the Global Warming Policy Foundation in November 2009 to campaign against Government policies.

Last month, he persuaded Owen Paterson, who was sacked as environment secretary earlier this year, to deliver a polemical speech on climate change in which he also denied the risks and attacked Government polices to reduce emissions.

However, with the accumulating evidence of the risks of climate change, Lord Lawson and his allies are having a tough time persuading MPs, except for a few Conservative backbenchers and UKIP, to enter a parallel universe where ideology trumps science.

Bob Ward is a Fellow of the Geological Society and policy and communications director at the Centre for Climate Change Economics and Policy and the Grantham Research Institute on Climate Change and the Environment at London School of Economics and Political Science.