THE world's top climate change expert has dissected The Great Global Warming Swindle, calling it "bad science".
Sir John Houghton, who lives in Aberdovey, Gwynedd, said the television programme, directed by Martin Durkin on Channel 4, "discredited the science of global warming".
Sir John is the former head of the Met Office who chairs the Scientific Assessment Working Group of the Intergovernmental Panel on Climate Change (IPCC).
He said, "Last Thursday's programme purported to debunk the science of Global Warming describing it as 'lies' and an invention of hundreds of scientists around the world, who have conspired to mislead governments, and the general public. The material presented was a mixture of truth, half truth and falsehood put together with the sole purpose of discrediting the science of global warming as presented by the main world community of climate scientists and by the IPCC."
He said the main lines of evidence for human-induced climate change were not addressed in the programme. This includes the growth of carbon dioxide in the atmosphere mainly due to fossil fuel burning and that observations of global warming at the earth's surface are consistent with the increase in greenhouse gases.
"The basic science of greenhouse gases has been known and understood for over 200 years," he said.
Sir John's verdict on the programme's claims were:
The most prominent person in the programme was Lord Lawson, former Chancellor of the Exchequer, "who is not a scientist and who shows little knowledge of the science".
The programme argued that changes in global average temperature over the past 50 years (and as projected for the 21st century) are within the range of natural climate variability, as observed over the last few millennia - not true.
Volcanic eruptions emit more carbon dioxide than fossil fuel burning - not true. None of the large volcanic eruptions over the last 50 years feature in the detailed record of increase in atmospheric carbon dioxide.
The troposphere is warming less than the surface - not true.
The IPCC process stifles debate and is used by scientists to further their own self interest - not true.
Solar influences are the main driver of global average temperature in the 20th century - not true.
Climate models are too complex and uncertain to provide useful projections of climate change - not true.
Sir John said the Academies of Science of the 11 largest countries in the world (the G8 plus China, India and Brazil) gave a clear and urgent message about the reality of global warming and its likely consequences and also endorsed the consensus of the IPCC at the G8 Summit at Gleneagles in 2005.
He said, "This statement by the academies is unprecedented.
"There could not be a stronger statement supporting the work of the world scientific community by the most eminent scientists in the world."
Gordon James of Friends of the Earth Cymru, said the programme was "misleading, inaccurate and damaging".
Mr James said, "I am pleased that someone as eminent as Sir John Houghton has highlighted the inaccuracies in the programme.
"But unfortunately a number of people seem to have been taken in by it, which can be damaging."
But a Channel 4 spokesman said the criticism was not fair.
He said, "All the programme does is put the views forward of a group of very eminent professors, who do not agree with the prevailing consensus of climate change, for various reasons.
"This is one of a series of programmes about climate change that aim to show all sides of the argument."