A Whale of a Climate Story

Save the whale and save the planet from global warming. Who'd a thunk?

The most direct way to slow climate change is to cut emissions of carbon dioxide (CO2) and other greenhouse gases. But that will require rebuilding our energy infrastructure and that's a heavy lift -- it will take changing habits, developing new technologies, and above all time. But we may not have the luxury of time to get there if we want to be assured of avoiding serious climate impacts. So taking as many innovative steps as we can (and as soon as we can) to get the ball rolling is key.

could whales help curb heat-trapping emissions
Whales live for many decades, keeping lots of carbon in their massive bodies and out of the atmosphere. When they die, unlike the carbon released as CO2 into the atmosphere when plants die, whale bodies keep sequestering carbon at the sea bottom. (NOAA)

One thing we can do is to coax the natural systems into absorbing a little extra CO2 from the atmosphere and storing or sequestering it where it can't do its global-warming thing. For example, an approach often touted is sequestering carbon in growing forests or grasslands.

Now Andrew Pershing of the University of Maine, Orono, and colleagues have hit upon a novel idea that probably has Captain Ahab rolling in Davy Jones's locker: bringing back the whale and in the process sequestering carbon in the deep blue sea.

Their idea, which appeared last week in the journal PLos ONE, is based on the fact that very large mammals like whales tie up lots of carbon just as grasses and forests do. How much carbon? Well, Pershing et al estimate that just three average-sized blue whales can remove as much carbon as an acre of grassland. Not bad. What's more, whales have a distinct advantage over grasslands and trees, which release carbon back to the atmosphere as CO2 when they die: whale carcasses tend to sink to the bottom of the sea, effectively removing most of their carbon for thousands of years.

Pershing et al suggest that restoring populations of all whale species to pre-industrial levels could remove up to 160,000 tons of carbon annually. This is comparable to preserving almost 2,100 acres of forest each year. And it doesn't have to be all or nothing either. For example, restoring just the blue whale population to the Southern Ocean would remove 70,000 tons of carbon annually, effectively offsetting the emissions of almost 13,000 Americans.*

But there is the problem of time. Bringing back the whales could take decades on decades, even centuries. The humpback whale, for instance, after shrinking to just 1,400 in the North Pacific before 1966, the year commercial whaling was banned, has some four decades later rebounded to an estimated 20,000. And yet the estimated 42,000 humpbacks that now populate all the world's oceans are a far cry from the pre-whaling estimates of 230,000.

Regardless of how long it would take, you gotta admit: it's a whale of an idea.



* The 13,000 statistic assumes that the average American emits about 20 tons of CO2 a year.

Crossposted with www.thegreengrok.com.