New study strengthens link between carbon levels and temperature

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.