The UN Secretary General Antonio Guterres says the world runs the risk of runaway climate change if it doesn't change course by 2020.
Mr Guterres says he's alarmed by the paralysis of world leaders on what he called the "defining issue" of our time.
He wants heads of government to come to New York for a special climate conference next year.
The call comes amid growing concerns over the slow pace of UN negotiations.
Despite the fact that the world agreed on a plan to tackle climate change in Paris in 2015, Mr Guterres said the world is way off track to achieve the modest goals of the pact.