How The Climate Could Rapidly Change

Scientific American excerpts The Fate of the Species:

Each year, the sun shines down on the dark surface of the Indian Ocean, and moist, warm air rises and forms clouds. This rising heat and the moisture form a powerful weather system, a natural pump that pulls up water and moves it in vast quantities hundreds of miles to the mainland. This is the Indian monsoon, which deposits rainfall on thousands of square miles of farmland. About a billion people, most of them poor, depend for their daily bread on crops that depend in turn on the reliability and regularity of the Indian monsoons.
India is a rapidly developing country with hundreds of millions of citizens who want to move into the middle class, drive cars and cool their homes with air-conditioning. It is also a country of poor people, many who still rely on burning agricultural waste to heat their homes and cook their suppers. Smoke from household fires has been a big source of pollution in the subcontinent, and it could disrupt the monsoons, too. The soot from these fires and from automobiles and buses in the ever more crowded cities rises into the atmosphere and drifts out over the Indian Ocean, changing the atmospheric dynamics upon which the monsoons depend. Aerosols (soot) keep much of the sun's energy from reaching the surface, which means the monsoon doesn't get going with the same force and takes longer to gather up a head of steam. Less rain makes it to crops.
At the same time, the buildup of greenhouse gases, coming mainly from developed countries in the northern hemisphere, has a very different effect on the Indian summer monsoons: it acts to make them stronger.
These two opposite influences make the fate of the monsoon difficult to predict and subject to instability. A small influence—a bit more carbon dioxide in the atmosphere, and a bit more brown haze—could have an out- size effect. Lenton believes that the monsoons could flip from one state to another as quickly as one year. What happens then is not a question that Lenton can answer with certainty, but he foresees two possibilities.

Neither potential outcome is good.  I'm afraid we are starting to see a similar possibility for the Corn Belt, but hopefully I am wrong.