Leaders must act now to prevent irreversible effects of climate change, say scientists

Governments are running out of time to avoid the “severe, pervasive, and irreversible” effects of climate change, leading scientists have said in a United Nations report.

The report said that global carbon emissions must fall by at least 40% by 2050 and to zero by 2100 to maintain warming below 2°C relative to pre-industrial temperatures. It said that dangerous global warming could be avoided but that delaying action would be costly and would increase risks to countries’ economies, global health, and food security.

The report was published in Copenhagen on 2 November by the Intergovernmental Panel on Climate Change, the world body for assessing the science related to climate change.1 2 It brings together findings from three major studies by panel working groups and was presented as the “most comprehensive assessment of climate change …