That is actually hard to say, which is one reason scientists are urging that emissions be cut; they want to limit the possibility of any worst-case scenario coming to pass. Perhaps the greatest fear is a collapse of food production, accompanied by escalating prices and mass starvation. Even with runaway emissions growth, it is unclear how likely this would be, as farmers are able to adjust their crops and farming techniques, to a degree, to adapt to climatic changes. Another possibility would be a disintegration of the polar ice sheets, leading to fast-rising seas that would force people to abandon many of the world’s great cities and would lead to the loss of trillions of dollars worth of property and other assets. Scientists also worry about other wild-card scenarios like the predictable cycles of Asian monsoons’ becoming less reliable. Billions of people depend on monsoons to provide water for crops, so any disruptions would be catastrophic