Michael E. Mann in Scientific American:
If the world continues to burn fossil fuels at the current rate, global warming will rise 2 degrees Celsius by 2036, crossing a threshold that many scientists think will hurt all aspects of human civilization: food, water, health, energy, economy and national security. In my article “False Hope” in the April 2014 Scientific American, I reveal dramatic curves that show why the world will reach this temperature limit so quickly, and also why the recent slowdown in the rate of temperature increase, if it continues, will only buy us another 10 years.
These numbers come from calculations made by me and several colleagues. We plugged values of Earth’s “equilibrium climate sensitivity”—a common measure of the heating effect of greenhouse gases—into a so-called energy balance model. Scientists use the model to investigate possible climate scenarios.
You can try this exercise yourself. The text below explains the variables and steps involved. You can download the climate data here and the model code here. And you can compare your results with mine, which are here. You can also change the variables to see what other future scenarios are possible. One note: the model runs on MatLab software, which can be obtained here.