Sir, During the past two weeks in Bali there has been a virtual obliteration in the media of any distinction between “climate change” (an observed reality) and “catastrophic man-made warming” (a disputed theory). This elision has been driven by celebrities, ecowarriors, demonstrators, bureaucrats and politicians. In the interests of sanity, may I draw attention to a few facts?

In distant ages, global temperatures swung violently between uninhabitably cold and warmer than now. Since the end of the Little Ice Age in the 18th century they have been recovering unevenly at about 0.7C per century.

It is scientifically credible that man has been making an added contribution to this warming since the Industrial Revolution, though we don’t know how much, and there are many unexplained discrepancies, including the 1940-1975 cooling, the stabilisation of temperatures since 1998 and the failure of some significant phenomena to replicate the IPCC’s models.

The effects of the Sun, water vapour, geothermal exchanges, aerosols, unreliable data series, oceanic and terrestrial carbon absorption, currents, volcanoes, etc are all crucial but as yet little understood. These elements interact in complex and mysterious ways. Chaos theory rules.

It is therefore time to end false certainties and denunciation of those scientists (and countries) that question the consensus. Taxpayers’ money would be best spent on independent research, clean water, forest protection, improved land use, flood defences and disease prevention rather than on pre-emptive avoidance, regardless of cost, of an unlikely disaster that — if it does occur — is probably beyond mankind’s control.

Lord Leach of Fairford

London EC3

Sir, In the Kyoto treaty and during the Bali discussions, critics have avoided the big gorillas in the room — China and India.

In 2004 (from which date the most comprehensive numbers presently available), the world output of industrial CO2 emissions was 27.2 million tons, of which the US produced 6 million tons and China and India produced 6.4 million tons.

Recent studies have China now dramatically surpassing the US in CO2 emissions. But much has been made in Bali of per capita emissions, where the US is still denounced as the biggest offender. But of course China and India have populations about eight times that of the US.

Let’s assume that the US reduces its CO2 emissions to 5 million tons. This means that, on a per capita basis, India and China would be entitled to emit a remarkable 40 million tons of CO2 emissions, this without regard to the emissions of the rest of the world. Let’s hope that what we are seeing is rather a part of long-term global temperature cycles.

Neil Gaffney

Chicago

Sir, It is surprising that the letter from chief executives of leading engineering institutions (Dec 18) makes no reference to the actual and potential capacity of nuclear power.

Surely our country’s diminishing record of expertise in this vital source of carbon-free energy deserves to attract all the technical skills we can muster, particularly with regard to the treatment of nuclear waste.

Jestyn Angus

Great Whittington, Northumberland

Explore Letters

• Feedback