Read an excerpt from al gore's nobel lecture.
last september 21, as the northern hemisphere tilted
away from the sun, scientists reported with unprecedented
distress that the north polar ice cap is "falling off a cliff."
one study estimated that it could be completely gone
during summer in less than 22 years. another new study,
to be presented by u.s. navy researchers later this week,
warns it could happen in as little as 7 years.
what evidence does gore use to support his argument about the dangers of
global warming?