Yet another encounter with the ubiquitous phrase "carbon footprint" (hopelessly vieux jeu) and a chance remark by Mrs. Laquedem spurred me to consider the effects of humankind on the other ninety-plus naturally occurring chemical elements. Two years ago I wrote about China using its near-monopoly over the element neodymium as an instrument of foreign policy, so let's start there.
Neodymium is one of the lanthanide series of metallic elements, commonly called "rare earths" although they are neither rare nor earthy. Neodymium's main use is as an ingredient in powerful magnets, including those in earphones. If you're listening to your iPod while you read this, you have some neodymium in your ears right now.
China has been the only supplier of neodymium from 1998 when a rare-earth mine in Mountain Pass, California closed for environmental reasons (here's some talk about that); the California mine reopened a few months ago.
Mining and refining the rare earth metals is a messy business: Bloomberg reports that China's rare earth mines produce five times more waste gas a year than all of the mines and oil refiners in the United States, and that waste gas is part of our neodymium footprint.
What else is in our neodymium footprint? Electric cars, for one thing; a Toyota Prius contains about 2 pounds of neodymium. Wind power, for another; Vestas uses 180 pounds of neodymium in its 3 megawatt wind turbine. Vestas may be efficient: The USGS, relying on an outside source from 2008, said that a wind turbine uses about 1 tonne of neodymium for each megawatt of generating capacity.
One metric ton ('tonne") of neodymium is enough for 1100 Priuses -- but then Toyota sells 500,000 Priuses a year, so it uses about 450 tonnes of neodymium a year, about 1/40 of the world's annual production. Neodymium is also in the Chevrolet Volt engine as well as in its Bose speaker system.
So who knew? When we drive our electric cars through the gorge and look at the wind farms, somewhere in China a hillside is crying because we stepped on it with our neodymium footprint.