Crop cultivation and farming was the greatest invention of man. Far more so than fire or the wheel, as it allowed man to spend time thinking, discussing and building communities, and not being forced to survive as a hunter gatherer.
Global warming is a bit of a myth, as the evidence seems to support the fact that we are entering into a new ice age. These are part of the natural cycles of the solar system, and this will cause some major problems and redistribution of wealth.
So what will be the most important industries? Probably the control of pollution and the protection of wealth and advantage. The other two major industries will be the expansion of the current global eugenics projects, and the extension of life for the elites.