The carbon footprint of industrial whaling

PORTLAND, Ore. — During the 20th century, industrial whaling activities depleted a storehouse of carbon equivalent to the forests of New England, a new study suggests.

Whales, a group of mammals that includes the largest animals ever to live, are huge repositories of carbon. Individual whales pack on carbon as they grow, typically increasing in weight between 1 and 3 percent each year. In addition to their great heft — a blue whale can weigh around 90 metric tons — whales can store carbon in biomass for well over a century. “In marine ecosystems, whales are like forests,” said Andrew J. Pershing, a biological oceanographer at the University of Maine in Orono. He presented his research February 25 at the American Geophysical Union’s Ocean Sciences meeting.

Industrial whaling — the use of large engine-driven ships to efficiently harvest whales — commenced in earnest around 1900, Pershing noted. That year, he estimates, the oceans held about 110 million metric tons of whales.

Over the course of the 20th century, whaling transferred more than 105 million tons of carbon from living whales into the atmosphere — an amount that equates to about 385 million metric tons of planet-warming carbon dioxide.

Those emissions are small potatoes compared to the approximately 7 billion tons of CO2 emitted by human activities each year. “Whaling did not cause global warming,” Pershing said.

Nevertheless, Pershing noted, the carbon footprint of last century’s industrial whaling is equivalent to that produced by driving 128,000 Hummers for 100 years, or by burning 130,000 square kilometers of temperate forest — an area equivalent to all the forests in New England.

From the Nature Index

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