James Watt designed a new kind of steam engine. Watt’s engine, it’s often said, anachronistically, “kick-started” the Industrial Revolution. As water power gave way to steam power, CO2 emissions began to rise, at first slowly, then vertiginously. In 1776, the first year Watt marketed his invention, humans emitted some fifteen million tons of CO2. By 1800, that figure had risen to thirty million tons. By 1850 it had increased to two hundred million tons a year and by 1900 to almost two billion.
