In 1955 I had a wonderful opportunity to participate in an expedition to observe a total solar eclipse in Ceylon. Thirty-two years later, in 1987, I was able to return to the eclipse site, and I was asked what did I notice that was different. I mused that Sri Lanka seemed much more crowded than Ceylon had been. That’s right, our tour guide responded. The population had doubled in those three decades. Since 1900 the entire world population has quadrupled. The physical mass of human beings and domesticated animals now makes up 90 percent of the vertebrate mass, up from 0.1 percent 10,000 years ago. The accelerating expansion of technological power, combined with the explosive growth of the world population and unsustainable consumption and production patterns, brings unparalleled challenges for the unity of nations. Already some centuries ago the expanding human population began to change the environment. Today, humans have modified more than 80 percent of Earth’s land surface.
more from Owen Gingerich at The American Scholar here.