A spreading plume of ash from an erupting Iceland volcano shut all British airports and effected air travel across northern Europe. The precautions reflect protocols developed after volcanic ash almost caused two disastrous crashes in 1982.
Iceland leads the list of the greenest nations. The US fell 22 places in the 2010 Environment Performance Index, but the study's researchers say that "murky" data makes the list imperfect.
Mount Redoubt, an active stratovolcano in the state's Aleutian Range, is twitching and belching like someone who just downed a case of Mountain Dew, signs that geologists say tend to precede an eruption.