Their argument is not predicated on a 20F+ temp rise globally; their argument is about regions.
Most of the increase in local temperatures are overnight lows in the Winter. I'm not sure there's any peer-reviewed mechanism to suggest that daytime Summer highs will increase 20F+ due to greenhouse gases in any parts of the world.
alt Hacker News
Most of the increase in local temperatures are overnight lows in the Winter. I'm not sure there's any peer-reviewed mechanism to suggest that daytime Summer highs will increase 20F+ due to greenhouse gases in any parts of the world.