Greenhouse Gasses Climb in 2007
Sharp Rise Seen in Carbon Dioxide and Methane Levels
Data released for the Annual Greenhouse Gas Index (AGGI) show a dramatic rise in atmospheric levels of carbon dioxide and major increases in methane.
In an annual update of its greenhouse gas index, the National Oceanic and Atmospheric Administration (NOAA) has measured a dramatic rise in the global levels of atmospheric carbon dioxide. This finding was accompanied by an increase of some 27 million tons of methane in the same time frame. These two gasses are seen as primary drivers of global climate change.
Annual Greenhouse Gas Index (AGGI) - The Global Monitoring Division of NOAA's Earth System Research Lab (ESRL) maintains the Annual Greenhouse Gas Index (AGGI). AGGI focuses on four primary greenhouse gasses, carbon dioxide, methane, nitrous oxide, and halogens. The index is an attempt to measure climate forcing or the changes related to the climate closely related to greenhouse gasses being introduced into the atmosphere. Annual climate forcing measures buildup of the gasses since the pre-industrial era before 1750, which is the index's basis. NOAA hopes the index will provide a common guide to measuring the impact of greenhouse gasses that can be easily embraced by the public.
Carbon Dioxide Levels - The primary source of carbon dioxide is the burning of fossil fuels like coal and oil. At current emission levels, the earth's environment can absorb half of this gas. Remaining carbon dioxide can remain in the atmosphere for centuries. The increase seen in 2007 raises the concentration of this greenhouse gas to nearly 385 parts per million (ppm), making it the third highest level enter measured. Historically, carbon dioxide levels were around 280 ppm until 1850.
A Shift in Methane Levels - Scientists saw the first increase measured in methane levels since 1998. This gas is a concern because it is 25 times more effective as a greenhouse gas than carbon dioxide. Methane occurs at much lower levels than those seen for carbon dioxide at about 1,800 parts per billion. At current concentrations, methane represents almost half the impact seen from carbon dioxide.
Sources of Methane - Rapid industrialization and increased emissions from Artic wetlands are likely sources of additional methane. In a press release announcing the annual greenhouse gas index, NOAA scientist Ed Dlugokencky says, ”We’re on the lookout for the first sign of a methane release from thawing Arctic permafrost. It’s too soon to tell whether last year’s spike in emissions includes the start of such a trend.”
Melting permafrost, the permanently frozen ground found in the arctic contains immense amounts of carbon. Scientists are concerned that climate change will warm permafrost, raising levels of methane even higher, spawning a vicious circle of global warming.
 |
 |
 |
 |
