Researchers and policy analysts have checked and double-checked future climate scenarios. We know how much carbon dioxide we can emit and still keep the world from getting more than 2ºC warmer, and we can use that number to determine how quickly we need to move away from fossil fuels. We have a variety of routes to get there, most of them involving replacing fossil fuels with the cheapest renewable energy sources: wind and solar power. From there, it's a simple matter of determining how quickly wind and solar use have to increase to get us there.
Wind and solar have become the cheapest sources of new electricity in most countries, and we now have massive economies of scale for their production and installation. We also have decades of experience with managing them effectively. There's little reason to think that these renewables aren't poised for explosive growth.
And yet a new study of the history of renewables shows that only a handful of countries have seen that sort of growth. And even when those countries achieved their goals, they only did so for a brief period.