Scientists have discovered that for the last 160,000 years, at least, there has
been a consistent relationship between the amount of carbon dioxide in the air and
the average temperature of the planet. The importance of carbon dioxide in
Line regulating the Earth's temperature was confirmed by scientists working in eastern
Antarctica. Drilling down into a glacier, they extracted a mile-long cylinder of ice
from the hole. The glacier had formed as layer upon layer of snow accumulated year
after year. Thus drilling into the ice was tantamount to drilling back through time.