A damning international report on mankind's role in climate change should be a wake-up call for urgent action, New Zealand environmentalists say.
The UN Intergovernmental Panel on Climate Change's draft fifth assessment report, released on Friday night, found it was "extremely likely" that humans were responsible for more than half the rise in global temperatures in the last six decades.
The landmark report, the IPCC's strongest warning yet, said if the world could not cap carbon emissions to one trillion tonnes, a budget already half spent, then global warming could not be held to within 2C.
The report said the world's climate would have warmed by at least that much by the end of the century, causing widespread extreme weather, drought and rising sea levels around the world.
The 2000-page report, which had some 250 lead authors and drew on thousands of peer-reviewed articles, updates the IPCC's 2007 report, which stirred controversy after critics found some errors.