Sabtu, 16 Mei 2015
CO2 methane up
Carbon Dioxide, Methane Rise Sharply in 2007
Last year alone global levels of
atmospheric carbon dioxide, the primary driver of
global climate change, increased by 0.6 percent,
or 19 billion tons. Additionally methane rose by
27 million tons after nearly a decade with little
or no increase. NOAA scientists released these
and other preliminary findings today as part of
an annual update to the agency’s greenhouse gas
index, which tracks data from 60 sites around the world.
The burning of coal, oil, and gas, known
as fossil fuels, is the primary source of
increasing carbon dioxide emissions. Earths
oceans, vegetation, and soils soak up half of
these emissions. The rest stays in the air for
centuries or longer. Twenty percent of the 2007
fossil fuel emissions of carbon dioxide are
expected to remain in the atmosphere for
thousands of years, according to the latest
scientific assessment by the International Panel on Climate Change.
Viewed another way, last year’s carbon
dioxide increase means 2.4 molecules of the gas
were added to every million molecules of air,
boosting the global concentration to nearly 385
parts per million (ppm). Pre-industrial carbon
dioxide levels hovered around 280 ppm until 1850.
Human activities pushed those levels up to 380 ppm by early 2006.
The rate of increase in carbon dioxide
concentrations accelerated over recent decades
along with fossil fuel emissions. Since 2000,
annual increases of two ppm or more have been
common, compared with 1.5 ppm per year in the
1980s and less than one ppm per year during the 1960s.
Methane levels rose last year for the
first time since 1998. Methane is 25 times more
potent as a greenhouse gas than carbon dioxide,
but there’s far less of it in the
atmosphere—about 1,800 parts per billion. When
related climate affects are taken into account,
methane’s overall climate impact is nearly half that of carbon dioxide.
Rapidly growing industrialization in Asia
and rising wetland emissions in the Arctic and
tropics are the most likely causes of the recent
methane increase, said scientist Ed Dlugokencky
from NOAA’s Earth System Research Laboratory.
”We’re on the lookout for the first sign
of a methane release from thawing Arctic
permafrost,” said Dlugokencky. “It’s too soon to
tell whether last year’s spike in emissions
includes the start of such a trend.”
Permafrost, or permanently frozen ground,
contains vast stores of carbon. Scientists are
concerned that as the Arctic continues to warm
and permafrost thaws, carbon could seep into the
atmosphere in the form of methane, possibly
fueling a cycle of carbon release and temperature rise.
NOAA is dedicated to enhancing economic
security and national safety through the
prediction and research of weather and
climate-related events and information service
delivery for transportation, and by providing
environmental stewardship of our nations coastal
and marine resources. Through the emerging Global
Earth Observation System of Systems (GEOSS), NOAA
is working with its federal partners, more than
70 countries and the European Commission to
develop a global monitoring network that is as
integrated as the planet it observes, predicts and protects.
On the Web:
http://www.esrl.noaa.gov/gmd/aggi
Langganan:
Posting Komentar (Atom)
Tidak ada komentar:
Posting Komentar