How much hotter? What concrete harms will result? How much can that be reduced by different levels of reduction in fossil fuel use? What are the harms from that reduction? How do those harms compare? What are the second order effects and their consequences for all of the above?

Now, let’s step back and accept that nobody actually has reliable answers to most of those questions. Further, nobody actually gets to make global policy choices. Even worse, the people who do make national policy choices don’t seem to make those choices based on collecting the best data and then rationally trying to serve the public interest.

Nether the “humanity will die” and “climate change isn’t real” claims are honest attempts to accurately predict the future. They are strategic attempts to influence public perception in a way that is hoped to lead to specific kinds of policy choice that benefit coalitions of special interests at the expense of most of humanity. Most people would be significantly better off if neither of those buckets of policies were implemented.