SINGAPORE — A team from the Chinese Academy of Sciences trekked
across frigid highlands in Tibet to confirm a significant recent
discovery about climate change. They drilled and analyzed five
ice cores from various locations on the Tibetan Plateau to find
that the concentration of black carbon, or soot, in the ice has
increased by two to three times since 1975. At Zuoqiupu Glacier,
on the southern edge of the plateau downwind from the Indian
subcontinent, black carbon deposition rose by 30 percent between
1990 and 2003. What are the implications of these and other
related findings in recent years by numerous researchers from
different countries and scientific agencies? International
efforts to combat global warming focus on cutting emissions of
six greenhouse gases from human activity. A panel of scientists
advising the United Nations has concluded that these gases —
chiefly carbon dioxide, methane and nitrous oxide — are most
likely to be responsible for warming the planet to potentially
dangerous levels. Ye