UN: Concentrations of greenhouse gases hit record

GENEVA
(AP) — Global warming gases have hit record levels in the world’s
atmosphere, with concentrations of carbon dioxide up 39% since the start
of the industrial era in 1750, the U.N. weather agency said Monday.

The
new figures for 2010 from the World Meteorological Organization show
that CO₂ levels are now at 389 parts per million, up from about 280
parts per million a quarter-millenium ago. The levels are significant
because the gases trap heat in the atmosphere.

WMO
Deputy Secretary-General Jeremiah Lengoasa said CO₂ emissions are to
blame for about four-fifths of the rise. But he noted the lag between
what gets pumped into the atmosphere and its effect on climate.

“With
this picture in mind, even if emissions were stopped overnight
globally, the atmospheric concentrations would continue for decades
because of the long lifetime of these greenhouse gases in the
atmosphere,” he said.

Negotiators
from virtually all the world’s nations will gather later this month in
South Africa to try to agree on steps to head off the worst of the
climate disruptions that researchers say will result if concentrations
hit around 450 parts per million.

That
could happen within several decades at the current rate, though some
climate activists and vulnerable nations say the world has already
passed the danger point of 350 parts per million and must somehow undo
it.

The
WMO said the increase of 2.3 parts per million in CO₂ in the atmosphere
between 2009 and 2010 shows an acceleration from the average 1.5 parts
per million increase during the 1990s.

But
there are seasonal fluctuations, too. During the summer growing season,
plants absorb carbon dioxide from the atmosphere. In winter, the
concentration of CO₂ rises as vegetation and other biomass decompose.

Since
1750, WMO says, atmospheric concentrations of CO₂ have risen 39%, those
of nitrous oxide have gone up 20 percent and concentrations of methane
jumped 158%.

Its report Monday cites fossil fuel-burning, loss of forests that absorb CO₂ and use of fertilizer as the main culprits.

SOURCE: The Associated Press