New
York Times: Although earlier studies had suggested that
after the last ice age, global temperatures rose hundreds of
years before the concentration of atmospheric carbon dioxide
did, new research indicates otherwise. To determine what
Earth's atmosphere and climate were like over the past 800 000
years, scientists have been examining core samples of ice
extracted from Greenland and Antarctica. Air bubbles trapped in
the ice give clues to Earth's past atmosphere, and the ice
itself can indicate the ambient air temperature when it formed.
Because the air bubbles and the ice that trapped them did not
form at the same time, however, it has been difficult to
ascertain the exact relationship between the two. With improved
dating techniques, Frédéric Parrenin of the
University of Grenoble in France and colleagues
have
narrowed the gap previously thought to exist. The findings
are important, writes Justin Gillis for the
New York Times, because climate change skeptics have
been using the earlier data as an excuse to delay action on
global warming by claiming that rising CO
2 levels were not connected with rising
temperatures.
