April 25, 2008
NOAA Reports Annual Increase of Greenhouse Gases
Researchers from the National Oceanographic and Atmospheric Administration Earth System Research Laboratory (ESRL) reported new data that shows a higher than usual average increase in carbon dioxide levels over the last 30 years.
The recently released report from NOAA scientists is an annual update to the agency's greenhouse gas index, which tracks data from 60 regions around the world. Concentrations may have increased by as much as 0.5% from 2006 to 2007.
CO2 levels jumped by 2.4 parts per million (ppm) from 2006 to 2007, compared with the average annual increase of only 1.65 ppm between 1979 and 2007.
It's not the increase in CO2 levels that concerns researchers. It's the fact that the rate of increase over time along with fossil fuel emissions has been accelerated.
Global concentration of CO2 reached almost 385 ppm, compared to pre-industrial carbon dioxide levels, which hovered around 280 ppm until 1850. Human activities pushed those levels up to 380 ppm by early 2006, they said.
Methane levels also increased between 2006 and 2007. Methane is 25 times more potent than carbon dioxide, although less of it exists in the atmosphere, making methane's overall climate impact nearly half that of CO2.
"Looking at the curve, there is a sign that methane is showing some increase," commented Geir Braathen, senior scientific officer with the World Meteorological Organization, who was not involved in the NOAA publication.
"But the mechanism behind that would be uncertain; and it's too early to say if this is the start of a new increase or not.
"We will need several years of increase before we can state that there is a rising trend."
The new data could be due in part by melting permafrost, growth of industrialization in Asia or drying of tropical wetlands, but the burning of coal, oil, and gas, known as fossil fuels, is the primary source of increasing carbon dioxide emissions researchers said.
"We're on the lookout for the first sign of a methane release from thawing Arctic permafrost," scientist Ed Dlugokencky from NOAA's Earth System Research Laboratory. "It's too soon to tell whether last year's spike in emissions includes the start of such a trend."
Image Caption: NOAA engineer Paul Fukumura-Sawada captures air near NOAA's Mauna Loa Observatory in Hawaii, using one of many methods to measure carbon dioxide and other greenhouse gases in Earth's atmosphere. Credit: NOAA
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