Earth will cross the climate danger threshold by 2026

I won't repeat the article from Scientific American; the author (Michael E Mann) says it better than I can.  You can read it here.  A key discussion in the article is how much global temperatures will rise if atmospheric CO2 doubles from the 280 ppm (parts per million) before industrialisation began to 560 ppm.  His estimate: 3 degrees centigrade.

The first chart below from the article shows different estimates of how much the world will warm based on different lines of evidence.

The second chart shows how temperatures will rise depending on just how sensitive the world's climate is to rising CO2.  In the article, the author points out that reducing aerosols (emitted along with CO2 by burning coal ) will cause global temps to rise.  So ironically, even as China slashes its emissions of CO2 global temps will rise/

Update, September 2026.  

First published in 2014, 12 years ago, Michael E Mann has been proved right.  We are well into the climate danger threshold.  Unprecedented heatwaves and droughts and bushfires in Europe, floods in China and Japan, record heat everywhere.  The so-famous "pause" the denialists talked about (the small black circled inset on the lower chart) was just a blip, as the climate scientists said it would be, and the temperature increase has accelerated.