Future BS risk.
. . . So how did they do this study? They based the projections on an ensemble output of 17 ‘state-of-the-art’ climate models and looked at two scenarios, RCP 8.5 and RCP 4.5. RCP 8.5 is the so-called ‘business as usual’ which is the track that we have continued to follow in reality for the last several decades. RCP 4.5 is the second rosiest projection that imagines that we'll get serious about cutting our emissions, levels will peak by 2040 and then start going down.
Let me spread a little cheer over your gloom. First, the CO2 emissions have been following RCP 8.5 since WWII, but temperatures are following an RCP 0 track for most of this period, and especially for the last 17 years. Second, the CMIP5 models have been found wanting in several respects. Given the task of simulating cloud and precipitation patterns for a water world with no topographical features to contend with, the models produced the disparate results shown below: (source)
Using the usual average over all of the models for a final projection results in obvious nonsense. Look at the precipitation in the equatorial zones in the bottom row. Anyone who believes that you can average models that produce contradictory droughts and floods to produce a credible prediction of the climate 50 years out deserves all of the angst that unfortunate lack of understanding might bring.