Subsistence farming dominated life before about 1800.
first in England and soon in many other parts of the world, people began to rise above subsistence. They specialized more narrowly than before in the production of certain goods and they traded with others who also specialized. This led to increased output, as specialists were able to produce more than generalists. Competition in the supply of goods drove innovation, which led to further increases in output. Agricultural production rose dramatically and famine declined. . . .
Since the 1920s, global deaths from drought-related famines have fallen by 99.9%. The reason? Continued specialization and trade, which has skyrocketed the amount of food produced per capita, and has enabled people in drought-prone regions to diversify and become less vulnerable.
In places where trade is restricted, people are forced to remain subsistence farmers. So, when drought occurs, the majority suffer and many die.