Speaking at a recent informal seminar with local journaiists in Cape Town, Leahy said climate change had become a polarised and politicised issue in North America as soon as scientific evidence had started to prove it was happening. The Bush administration had tried to control media access to government scientists, with scientists being instructed on what questions to answer. In Canada, the conservative government had had a similar gagging order on government scientists and journalists had had to seek permission from the prime minister’s office before interviewing an expert.

“In some cases political appointees re-wrote scientific reports to suit their agenda,” he said.