Today's Tidbit: Sea Otters Help Us Fight Global Warming

Sea otters are the largest members of the weasel family.

When people started hunting sea otters for their fur, their population fell from roughly 225,000 to about 1,500, until the International Fur Seal Treaty took effect in 1911. Since the international ban on otter hunting, the population has rebounded back to roughly 107,000.

Why does this matter?

Because sea otters eat sea urchins, and sea urchins eat sea kelp, and sea kelp eats carbon dioxide, and carbon dioxide causes global warming. That means that the more sea otters there are, the more kelp there will be to absorb CO2 from the atmosphere.

Although hard to believe, Chistopher Wilmers, among others, estimate that because of existing sea otters, roughly 6.5 million more metric tonnes of carbon is stored in sea kelp than would be otherwise. With carbon futures currently trading at around $15 per metric tonne, this is worth roughly $100 million.

That's $1,000 per otter.

So, the next time you're shopping for an otter coat, remember that if we kill off all the otters for their fur, and the world heats up, you won't have any use for the coat.

References:

• "Do trophic cascades affect the storage and flux of atmospheric carbon? An analysis of sea otters and kelp forests" 2012 article by Christopher C. Wilmers, James A. Estes, Matthew Edwards, Kristin L. Laidre, and Brenda Konar, in Frontiers in Ecology and the Environment, Volume 10, Issue 8.
• Kornev S.I., Korneva S.M. (2004) Population dynamics and present status of sea otters (Enhydra lutris) of the Kuril Islands and southern Kamchatka. Marine Mammals of the Holarctic, Proceedings of 2004 conference
• "Final Washington State Sea Otter Recovery Plan". Washington Department of Fish and Wildlife. Archived from the original on October 18, 2007