Scientists have long warned that failure to halt or significantly slow greenhouse gas emissions would do irreparable harm to the Earth, society and civilization. Crucial thresholds for change are ever nearer — because time has passed and those deadlines are more proximate and because the pace of change is accelerating. The Intergovernmental Panel on Climate Change (IPCC), in the most authoritative assessment of climate change, has released its latest report and the conclusions are grim: Keeping global warming below a critical limit demands "rapid, far-reaching and unprecedented changes in all aspects of society." Immediate action is required, but history gives us little reason to be optimistic.
The IPCC is a scientific body under the United Nations, set up in 1988 to provide authoritative assessments of climate change. It shared the 2007 Nobel Peace Prize with environmental activist and former U.S. Vice President Al Gore. Membership is open to all members of the World Meteorological Program and the U.N. Environmental Program. It does not conduct its own analysis but instead assesses published literature.
After the 2015 Paris climate agreement, the IPCC was tasked with providing a special report to detail impacts of climate change of 1.5 degrees Celsius, what will be required to prevent further warming, and mitigation and adaptation options to deal with those impacts. Nearly 100 authors from 40 countries, along with 133 contributing authors, joined the effort: A 34-page "summary for policymakers" that cited more than 6,000 articles and studies was presented Monday at the 48th Session of the IPCC, which was held in Incheon, South Korea.