In 1865, William Stanley Jevons wrote a book called The Coal Question, in which he observed that the use of coal shot up after James Watt improved on Thomas Newcomen's steam engine by making it more efficient. He reasoned that efficiencies in energy-use only created more demand for energy. The Jevons Paradox is one of the big challenges in environmental economics, which is why most environmentalists should focus on the demand side of the problem, rather than the supply side. The Jevons Paradox has been ignored by Amory Lovins, who has predicted that the cumulative energy savings from gains in efficiency since 1975 are 30 times more than the increased supply from renewable energy.^[https://www.greenbiz.com/article/biggest-resource-we-dont-use-qa-amory-lovins-energy-innovator]