Politicians were willfully ignoring and misunderstanding the science of global warming, a government adviser said today.

John Ashton, who is the Foreign and Commonwealth Office's special representative on climate change, warned scientists that they could not trust in the honesty of politicians.

Speaking at the start of the climate change conference in Copenhagen, Denmark, Mr Ashton said that the truth could be lost to political expediency or mischief and urged scientists to couch their conclusions in terms that could not be misunderstood or go unheard.

Delegates at the conference will again meet in the city later this year in an attempt to reach an international deal on how to combat global warming.

Mr Ashton, who trained as a physicist before becoming a diplomat, said that researchers had been tremendously successful in analysing climate science but had yet to succeed in making political leaders understand the importance of their discoveries.

"In science the truth is out there. It's there to be discovered. In politics often the truth is whatever is expedient to this or that project," he said in the opening session of the conference.

Urging the scientists to speak the language of politicians, he said: "We need to do this better to stand any chance of keeping climate change on the right side of the last acceptable risk. There has to be much better communication between the world of science and the world of politics."

Of particular concern was the different meaning of the word uncertainty to scientists and politicians. To the former it meant uncertainty over the strength of a signal, to the latter it meant "go away and come back when you're certain".

He said: "There are plenty of people who for reasons of either ignorance or mischief are ready to confuse one type of uncertainty with the other."

Speaking outside the conference hall, he added: "There are plenty of people in the political world who are quite happy to abuse the [scientists' conclusions] to serve political purposes. Politics is a shark-infested sea.

"The more effort scientists put into how their message might be heard, how it might be manipulated and made mischief of, the better."

Mr Ashton also told scientists that if they wanted to be listened to in the current political climate, they needed to show that tackling climate change was an economic opportunity.

"Politicians around the world are going to be focussed on one big thing and that is going to be jobs, jobs, jobs," he said.

"If we want to successfully respond to climate change we have to form it as part of the solution to the economic crisis."

Times recommends

• Energy-saving ideas from switched-on professor
• Rooks are as clever with tools as chimpanzees
• Burping of the lambs blows roast off menu