> then 4C is unavoidable Is this estimate of yours based on anything or just gut feeling? I like to draw a comparison with world wars. As a fraction of GDP, t

> then 4C is unavoidable Is this estimate of yours based on anything or just gut feeling? I like to draw a comparison with world wars. As a fraction of GDP, the world spent more on WW2 than what is needed to solve climate change. Having such a war was also hard, took real effort, people cheated, pointed fingers, etc. Also, lot of people died. But we did it anyway. So it's an important and interesting question what exactly it takes for countries to go into emergency mode and take action on such a scale. Working it out seems really hard though. To get to something like your "4C" figure, you would have to look at what kind of catastrophes and damage need to happen to force how much investment into a solution (I guess this is very hard, one would consider a number of possible scenarios), how soon we expect such catastrophic consequences to happen at places where a lot of people live, how much action we can reasonably expect they will take, and how much that action will actually help. The people that The Guardian asked presumably also tried to take all of this into account and arrived at less than "3C".