The other global warming

Human civilization will heat up the planet; the glaciers will melt and the seas will rise. It’s a familiar refrain by now, with a familiar solution: stop pumping out the greenhouse gases that trap the sun’s heat.

But even if we bring the greenhouse effect under control, says a Tufts astrophysicist, the earth will warm up anyway, thanks to a completely different source of heat that we create ourselves.


Over the next 250 years, calculates Eric J. Chaisson in a recent paper, the earth’s population will start generating so much of its own heat – chiefly wasted from energy use – that it will warm the earth even without a rise in greenhouse gases. The only way to avoid it, he says, is to rethink how we generate energy.

His paper examines the planet’s growing pool of waste heat, a widespread phenomenon that nonetheless has been little studied as a cause of climate change. Nearly everything that uses or generates energy – chiefly power plants, but also cars, snowblowers, computers, and light bulbs – squanders some energy as wasted heat. And the larger and more energy-hungry the human population grows, the more waste heat remains in our atmosphere.

“What this means for humans is that this is the ultimate limit to growth,” said Dennis Bushnell, the chief scientist at NASA’s Langley Research Center, who urged Chaisson to publish his idea. “As we produce more kilowatts, we have to produce more waste heat.”

Boston Globe