Human effect on climate 'beyond doubt'

Sir John at the Shanghai meeting: "Climate change is the biggest environmental threat"

By environment correspondent Alex Kirby

One of the world's leading climatologists says he is certain that human activities are warming the world.

He is Sir John Houghton, the co-chair of Working Group One of the Intergovernmental Panel on Climate Change (IPCC).

The group's third assessment report on the science of climate change says global warming is happening faster than previously predicted. And it says it is "likely" that pollution caused by humans has contributed "substantially" to the warming seen over the last half century.

Sir John was for years director of the UK Meteorological Office, and is a former chairman of the UK Royal Commission on Environmental Pollution.

He has been co-chairing the working group's meeting in Shanghai, China, which agreed the report. Speaking to BBC News Online from Shanghai, Sir John said: "I don't feel personally there can be any doubt about the human effect on climate.

"The evidence is certainly sufficiently strong for countries to take action based on what we've said.

Oil-producing countries

"It's a highly authoritative report. We're fortunate to have had the best people in the world working on it. Here in China, there've been 99 countries at the meeting, including Saudi Arabia and other oil states. No big country was absent.

"And yet the meeting ended with the report being agreed unanimously.

Washington will ponder the report

"It had been reviewed by governments before we came here, and in fact it's probably one of the most peer-reviewed documents you could ever find."

The new US president, George W Bush, has expressed scepticism about the reality of climate change, though early signs suggest that his administration takes it seriously. Sir John, in any case, believes that Americans will sit up and take notice of the IPCC report.

He said: "I hope the White House will read the report very carefully, and realise that it's been put together by leading scientists. They need to take it very seriously and to begin to lead the world in taking action.

"The technology is there to do something about it. Energy efficiency, alternative energy sources, even carbon sequestration - none of them would cost very much.

Optimistic view

"Industry will see the logic of acting, and although it will need incentives from government it will find itself being prompted by demands from consumers.

"Drastic changes in lifestyle are not what we're talking about. There'll still be cars - but they'll be much more efficient. I'm really optimistic that the report will lead to action, even in the US."

Cars could easily be far more efficient

Asked whether as a scientist he had been taken aback by any of the report's findings, Sir John said in one respect he had.

"I'm surprised at how little it turns out we need to do to the climate to produce a substantial change," he said. "To see the signal of human activity emerge above the noise of natural climate change is in a way a scientific surprise."

And he had some advice for those who still remained sceptical about the phenomenon.

"They should look at the evidence which has been collected by some of the world's leading scientists," he said. "I think there are very few scientists who'd disagree with the IPCC. And most of those who do disagree have not published much.

"I'm sure climate change is the biggest environmental threat that faces the world, and it's linked to so many others. When some of the impacts begin to bite, they'll worsen the poverty in which so many people are already existing."