The cost of taking no action to reduce greenhouse gas emissions would be “equivalent to a 3.6% loss of the U.S. GDP in 2100,” said Sir Nicholas Stern in his written testimony to the Energy and Commerce Subcommittee on Energy and Air Quality last week (archived webcast). “We should emphasize, however, that there are many likely, larger, and deeply damaging, effects which will occur after 2100 and these calculations take no account of the effects on the USA of the damages and devastation which occur outside the USA.”

Stern, who authored the 2006 Stern Review on the Economics of Climate Change, discussed the non-economic costs of climate change, as well. Extreme climate change scenarios “involve movements of population, and we know that movement of population means not only the hardship around the movements themselves, but also conflict,” he said at the hearing.

Sherri Goodman, general counsel of the Center for Naval Analysis (CNA) Corporation, asserted the interdependence of climate change, national security, and energy dependence. “Numerous DoD studies have concluded that high fuel demand by combat forces detracts from combat capability, makes our forces more vulnerable, diverts combat assets from offense to supply line protection, and increases operating costs,” said Goodman’s testimony.

Energy is also a security issue at home. “The Defense Department is almost completely dependent on electricity from the national grid to power critical missions at fixed installations,” explained Goodman. “The national electric grid is fragile and can be easily disrupted, as happened in the Northeast Blackout of 2003, caused by trees falling onto power lines in Ohio. It affected 50 million people in eight states and Canada, took days to restore and caused a financial loss in the U.S. estimated to be between $4 billion and $10 billion. As extreme weather events become more common [due to climate change], so do the threats to our national electricity supply.”

A day earlier, two other House committees discussed the newly completed—and still classified—National Intelligence Assessment on the U.S. national security implications of climate change.