Thu April 5, 2012 Shake It Off: Earth's Wobble May Have Ended
Ice Age The last big ice age ended about 11,000 years ago, and
not a moment too soon — it made a lot more of the world livable,
at least for humans. But exactly what caused the big thaw isn't
clear, and new research suggests that a wobble in the Earth
kicked off a complicated process that changed the whole planet.
Ice tells the history of the Earth's climate: Air bubbles in ice
reveal what the atmosphere was like and what the temperature
was. And scientists can read this ice, even if it's been buried
for thousands of years. But when it comes to the last ice age,
ice has a mixed message. The conventional wisdom is that carbon
dioxide increased in the atmosphere starting about 19,000 years
ago. Then the ice melted. The logical conclusion? The greenhouse
effect. But the Antarctic was getting warmer even before CO2
levels went up. So which came first in the Antarctic, warming or
CO2? "The problem is, [the Antarctic is] just one spot on the
map, and it'