Major U.N. climate report warns of "extreme" and "unprecedented" impacts

From flood to fire, 2021 has been a summer of extraordinary extremes across the globe — a sign that the impacts of climate change are already widespread and accelerating. Such extremes, and their connection to human-caused climate change, are just one main theme in a landmark climate report released Monday by the U.N.'s Intergovernmental Panel on Climate Change (IPCC).

Written by more than 230 leading scientists from countries around the world, it is part of the IPCC's Sixth Assessment Report — the most significant climate report published in years by the international science community.  The report is a synthesis of work from over 14,000 research citations. It is, in effect, a climate science encyclopedia — a summary of the latest scientific consensus on climate change and what the future portends, through the use of sophisticated climate models and knowledge of past conditions. It is an update on how the Earth's climate and our understanding of it have changed since the last such report in 2013.