Turn down the heat: why a 4 degrees warmer world must be avoided (climate change)

This report provides a snapshot of recent scientific literature and new analyses of likely impacts and risks that would be associated with a 4` Celsius warming within this century. It is a rigorous attempt to outline a range of risks, focusing on developing countries and especially the poor. A 4`C world would be one of unprecedented heat waves, severe drought, and major floods in many regions, with serious impacts on ecosystems and associated services. But with action, a 4`C world can be avoided and we can likely hold warming below 2`C.