Earth feels impact of middle class
Our most pressing environmental challenge is not how many people the planet can support, but rather how many cellphone-toting, satellite-TV-watching, gas-guzzler driving members of the middle class it can bear. That was the message from Sir David King, former science adviser to the British government, chancellor of the University of Liverpool, and director of research in physical chemistry at the University of Cambridge, who spoke at Harvard’s Science Center on April 17. While global population growth has been important over the last century, as the number of humans climbed from 1.5 billion in 1900 to some 7 billion today, average female fertility has declined to the replacement value of 2.1 births, King said. While a significant increase of some 2 billion people is still expected as today’s children reach childbearing age, lifestyle changes are the greater challenge, he said. The global middle class — defined as those who spend between $10 and $100...