Valuable new paper on climate catastrophes

A group of scientists have published a paper on the dangers of catastrophic climate change that sets 3°C as a line beyond which we risk climate changes so severe that they could imperil the existence of human civilisation, if not the human species itself:

We have set global warming of 3°C or more by the end of the century as a marker for extreme climate change.

Academic studies have warned that warming above 5 °C is likely to be “beyond catastrophic”, and above 6 °C constitutes “an indisputable global catastrophe”.

These warnings by scientists about the dangers that global warming poses provide an effective counterpoint to the nonsense from economists like Nordhaus that 6°C will only cause an 8.5% fall in GWP (Gross World Product):

Including all factors, the damage equation in the model assumes that damages are 2.1 percent of global income at 3°C warming and 8.5 percent of income at 6°C warming. (Nordhaus, W. (2018). "Projections and Uncertainties about Climate Change in an Era of Minimal Climate Policies." American Economic Journal: Economic Policy 10(3): 333–360.)

Though the topic is heavy, it's not a hard paper to read: it is an overview rather than an analytic or modelling paper. I highly recommend reading it.

The URL is https://www.pnas.org/doi/epdf/10.1073/pnas.2108146119, and it’s Open Access. If you're on social media, please retweet the original URL, since that will raise its visibility. 

Kemp, L., C. Xu, J. Depledge, K. L. Ebi, G. Gibbins, T. A. Kohler, J. Rockström, M. Scheffer, H. J. Schellnhuber, W. Steffen and T. M. Lenton (2022). "Climate Endgame: Exploring catastrophic climate change scenarios." Proceedings of the National Academy of Sciences 119(34): e2108146119.