Doing calculations and modeling of climate change is a very big and complicated problem. For modeling there are just not enough sensors to measure tempature around the globe, and modeling interactions between phenomna is nearly impossible.
Also, there are big surprises around every corner, such as discovering the oceans hold 40% more heat than was thought. And, of course, it is impossible to tell what different nations are going to do. So far they have almost ignorned, or if not ignored, have not figured out how to make their goals. And although they have worked hard as India has, they can barely keep up with their grownth.
Not having data, nor computer models, nor super-computers to work with I decided to try the most basic of predictions: extrapolation from existing data by curve fitting. The resulting curve is shown below. To whatever degree this can give a valid predictions it is in the general area of other's calculations. And, the exact prediction is not critical. The salient point is that we are at or near the inflection point of a power curve. From here on the first derivative (slope) of the curve keeps increasing. This means that not only does the temperature increase but it keeps increasing faster, all based on emissions as usual.
And the numbers are simply unacceptable not only at the end of the century but in the next 10 years. Which is where the "green deal" comes in. We either act, around the world, but espically in the nations with high carbon output and in those nations whose ouput is increasing. India is a good model. Or as I have said twice already, continuing what we have been doing or worse (US), we are finished. In other words, like the squeeling microphone in a public sound system one positive feedback, namely more heat causes the heat generated to increase and then to increase faster, the squeeling takes over and we are helples. Or perhaps you could say, if you are going to tame a tiger, you should start young, and we did not do that.
Various commentators blithly say we will have to deal with 3°C heat rise, I would argue that if we go beyond 2° it is too late and there is no way to predict that 1.5° is not too late.
The only rational way to proceed is to go onto a war footing to decrease emission. If you are a billionaire, prepare for a very high incremental tax rate unless you are investing in one of the critical technologiess. Alternatively, you can run away from what engineers call thermal runaway.
The next 10 years will determine the fate of the world.