The world’s governments must act quickly to develop policies that shift their economies from reliance on fossil fuels to renewable energy, a global report says.

It warns climate change is happening much faster than predicted and many aspects of the Earth’s climate including rising temperatures and frequency of extreme weather events. It calls for ”aggressive mitigation portfolios” to be adapted to help cut greenhouse gas emissions.

The report was published by the University of Copenhagen and contains contributions from some 1,600 scientists, including British economist Sir Nicholas Stern. It warns that if governments set weak emission reduction targets for 2020, it will increase the risk of impacts ”including the crossing of tipping points, and make the task of meeting 2050 targets more difficult.”

Green transport systems, smart energy grids, sustainable farming systems, and a massive investment for renewable energy technologies are among the recommendations the report makes for world governments.