Normally, I'd never trust any politician. However, Lawson's assessment is based on that of a cross party report of the House of Lords economics commitee. And don't forget, he was the one who instigated the initial research into global warming, telling the scientists to look for climate change problems. Maggie Thatcher wanted the country to move to nuclear power in order to reduce the nation's dependence on coal mines, so they asked scientists to come up with reasons why nuclear power would be preferable to fossil fuels.
You can't blame the scientists for finding what they saw as potential problems, worthy of further research. It was in their best interests, a bit like priests who tell us to keep funding the churches so that God won't visit his displeasure on us. The more the scientists researched the matter, the more worried they became by what they didn't know. So they started writing reports which intimated that further research was needed into potentially cataclysmic side effects of burning fossil fuels.
This is why I'm so keen to find what all their research has produced. For almost thirty years, scientists have been researching global warming, yet all their reports alway seem to be couched in vagaries, relying on inconclusive data. They might as well join Yvette Fielding on 'Most Haunted' - she spooks the public too, without ever producing proof.