Recently , three mysterious craters were discovered in the Siberian permafrost . Alan Weisman : Hot summers caused Earth to spew methane , resulting in explosions . He says airborne methane is more potent in producing greenhouse effect . The last time there was this much atmospheric CO2 was 3 million years ago , when seas were 80 to 100 feet higher . Comment: Such stunning global flatulence is deadly if we do n't embrace green energy .
Recently , three mysterious craters were discovered in the Siberian permafrost . Alan Weisman : Hot summers caused Earth to spew methane , resulting in explosions . He says airborne methane is more potent in producing greenhouse effect . Comment: Such stunning global flatulence is deadly if we do n't embrace green energy .