"We humans emerged as a species about 200,000 years ago. In geological time, that is really incredibly recent. Just 10,000 years ago, there were one million of us. By 1800, just over 200 years ago, there were 1 billion of us. By 1960, 50 years ago, there were 3 billion of us. There are now over 7 billion of us. By 2050, your children, or your children's children, will be living on a planet with at least 9 billion other people. Some time towards the end of this century, there will be at least 10 billion of us. Possibly more. We got to where we are now through a number of civilization-and society-shaping “events”; most notably, the agricultural revolution, the scientific revolution, and—in the West—the public-health revolution. These events have fundamentally shaped how we live, and have fundamentally shaped our planet. Their legacy will continue to shape our future. So we need to look at our growth and activities through the lens of these developments. One of the principal reasons for this growth was the invention of agriculture. The “agricultural revolution” enabled us to go from being hunter-gatherers to highly organized producers of food, and allowed our population to grow. A useful way to think of the development and importance of agriculture is in terms of at least three agricultural “revolutions.” The first took place over 10,000 years ago. This was the domestication of animals and the cultivation of plant types. The second agricultural revolution was between the fifteenth and nineteenth centuries. This was a revolution in agricultural productivity and the mechanization of food production. The third happened between the 1950s and 2000s; the so-called “green revolution.” But there’s another story here: the start of a fundamental transformation—of land use—by humans."