A group of United Nations scientists warned Monday that humanity is close to its last chance to prevent the worst of climate change. The Intergovernmental Panel on Climate Change (IPCC) said the world will need to cut carbon pollution and fossil fuel use by nearly two-thirds by the year 2035. The scientists called for an end to new fossil fuel exploration. And they urged countries to stop using coal, oil and gas by 2040. “Humanity is on thin ice and that ice is melting fast,” U.N. Secretary-General Antonio Guterres said. “Our world needs climate action on all fronts everything, everywhere, all at once.” Guterres not only called for “no new coal” but also called for ending its use in rich countries by 2030 and in poor countries by 2040. He called for carbon-free electricity generation in the developed world by 2035. That is the year that nations have to come up with goals for pollution reduction under the Paris climate agreement.