Working group 1 published The Physical Science Basis of Climate Change on 9 August 2021, which said that, if greenhouse gas emissions are halved by 2030 and net zero by 2050, global warming can be stopped.[2] The report's 234 authors[2] built on more than 14,000 scientific papers and then approved by 195 governments.[4] The summary for policymakers was drafted by scientists and agreed to line-by-line by governments during the 5 days leading up to 6 August 2021.[3]