“Global methane (CH4) concentrations rose in 2007 for the first time in 10 years. Methane, a greenhouse gas is 20 times more potent than carbon dioxide.
Last year alone global levels of atmospheric carbon dioxide, thought to be a primary driver of global climate change, increased by 0.6 percent, or 19 billion tons. However 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 these are things we can control. Earth’s 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).(1)
Methane is increased through the oil and gases that are oozing up from the seafloor. Then bubbles up through the ocean water and finally releases into the atmosphere. This process causes oil slicks to be deposited on the ocean’s surface. When the oil evaporates, a thick black tar remains behind and sinks, becoming part of ocean-bottom sediments again. Methane hydrate—a solid form of methane embedded in glacier deposits—is the catalyst that touches off this warming cycle, Dr. Hill believes.
“As glaciers begin to melt, methane hydrate is expelled from lattices of frozen water molecules.
“When methane hydrate is released, you have a lot of sediment movement. Landslides can occur, and you get big pockmarks in ocean sediments where bubbles of methane come out,” Hill said.
Despite methane’s potential to accelerate global warming, the University of California’s Hill says that no reliable cleanup strategy has yet been developed. (yet-M.Nature’s comment) “We can’t control this particular source of methane,” she said. “The wiser thing to do would be to think about controlling our overall greenhouse gas emissions. There’s a lot more carbon dioxide than methane in the atmosphere.”(2)
1. NASA Measurements Show Greenhouse Gas Methane on the Rise Again October 29, 2008
2. Global Warming Feedback Loop Caused by Methane, Scientists Say -Elizabeth Svoboda
National Geographic News August 29, 2006
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