Climate change is hard to hide, but the U.S. Central Intelligence Agency is trying anyway.

Back in 2009, the CIA established a Center on Climate Change and National Security dedicated to researching the implications of rising sea levels, declining agricultural yields and other climate change impacts.

A National Security Archive historian asked the CIA for a copy of any impact studies or reports the center has done in March 2010. But the CIA responded (pdf) this September that such material is quote "currently and properly classified and must be denied in its entirety."

The CIA claims to be concerned about the "protection of intelligence sources and methods, names, official titles, salaries, and numbers of personnel."

But is it a secret that satellites and ground observations show a meltdown in Arctic sea ice that will open new shipping lanes—and security concerns—for the first time in recorded history? To take just one example.

Climate change impacts and their security implications appear almost wherever science looks. In fact, physicist Richard Muller and his group at the University of California at Berkeley confirmed this week that global average temperatures have been rising. Again. That's no secret.

—David Biello

[The above text is a transcript of this podcast.]