UN: greenhouse gases at new record
Nov 25, 2008 - Eliane Engeler - The
Greenhouse gases in the Earth's atmosphere
have reached new record highs and show no sign of
leveling off, the U.N. weather agency said Tuesday.
Major greenhouse gases have been increasing
every year since detailed records started being kept
in 1998 and follow a trend of rising emissions that
began with the Industrial Revolution in the mid-18th
The report by the World Meteorological
Organization was released a year before representatives
from major countries meet in Copenhagen, Denmark,
to negotiate a new international treaty to curb greenhouse
gases for 2012 and beyond.
The gases - carbon dioxide, or CO2;
nitrous oxide, N2O; and methane - are produced partially
by natural sources, such as wetlands, and partially
by human activities such as fertilizer use or fuel
"CO2 and N2O are increasing steadily
... and there is no sign of leveling off," said Geir
Braathen, a climate specialist at the Geneva-based
agency. Methane also has been rising, but its growth
had been slowed until last year.
Carbon dioxide was up most in 2007,
the latest year for which figures are available. It
increased to 383.1 parts per million, one-half percent
more than the 2006 amount. Methane and nitrous oxide
rose by lesser amounts, the WMO said.
Nitrous oxide increased by 0.25 percent
over the previous year to 320.9 parts per billion.
Methane concentrations in the atmosphere
soared to the highest annual increase measured since
1998, Braathen said. The gas was at 1,789 parts per
billion last year - a 0.34 percent increase from 2006.
Braathen said that it was too soon to
say what had caused the increases.
The WMO's annual Greenhouse Gas Bulletin
2007 provides widely accepted worldwide data on the
amount of heat-trapping greenhouse gases in the atmosphere.
Studies have shown that human-produced
carbon dioxide emissions heat the Earth's surface
and cause greater water evaporation. That leads to
more water vapor in the air, which contributes to
higher air temperatures.
CO2, methane and N2O are the most common
greenhouse gases after water vapor, according to the
"CO2 alone is responsible for 90 percent
of the greenhouse gas warming over the last five years,"
There is 37 percent more carbon dioxide
in the atmosphere than there was in the mid-18th century,
primarily because of combustion of fossil fuels, the
WMO bulletin said.
A Nobel prize-winning panel of U.N.
scientists has said emissions must level off within
the next 10 to 15 years and then start to dramatically
decline to avoid a rise in average temperatures that
could have catastrophic consequences, such as severe
droughts and flooding.