CMIP5 Projected Global Warming
120
Published 2016-02-21
Data: http://climexp.knmi.nl/plot_atlas_form.py
Impacts are non-linear. The first degree of warming may have been beneficial, or only marginally harmful. The second degree is expected to have a net negative effect. The third degree is expected to have a large negative effect. 4.5 degrees is an "Ice Age Unit" https://xkcd.com/1379/