Guest post by Steven Goddard
Cartoon by Josh: http://www.cartoonsbyjosh.com
The climate panic headline this week has been that the warming Arctic is burping out dangerous quantities of greenhouse gas Methane.
Published on Friday, March 5, 2010 by Agence France Presse
Huge Methane Leak in Arctic Ocean: Study
WASHINGTON – Methane is leaking into the atmosphere from unstable permafrost in the Arctic Ocean faster than scientists had thought and could worsen global warming, a study said Thursday. From 2003 to 2008, an international research team led by University of Alaska-Fairbanks scientists Natalia Shakhova and Igor Semiletov surveyed the waters of the East Siberian Arctic Shelf, which covers more than 772,200 square miles (two million square kilometers) of seafloor in the Arctic Ocean. “This discovery reveals a large but overlooked source of methane gas escaping from permafrost underwater, rather than on land,” the study said. “More widespread emissions could have dramatic effects on global warming in the future.”
Methane is 30X more potent a greenhouse than CO2, so this sounds very alarming. Or does it? From the New York Times:
Dr. Shakhova said that undersea methane ordinarily undergoes oxidation as it rises to the surface, where it is released as carbon dioxide. But because water over the shelf is at most about 50 meters deep, she said, the gas bubbles to the surface there as methane. As a result, she said, atmospheric levels of methane over the Arctic are 1.85 parts per million, almost three times as high as the global average of 0.6 or 0.7 parts per million.
The first problem with the statement is that it is incorrect. The average global methane concentration is ~1.8 ppm, (1786 ppb) not 0.6 ppm as seen below in this graph from NOAA:
http://www.noaanews.noaa.gov/stories2008/images/methanetrend.jpg
The author also says that the Arctic is belching out nearly eight million tons of methane per annum.
She estimated that annual methane emissions from the East Siberian Arctic Shelf total about seven teragrams. (A teragram is 1.1 million tons.)
Sounds like a big number – except that burping/flatulating cattle produce ten times more methane than the Arctic. According to the EPA:
Globally, ruminant livestock produce about 80 million metric tons of methane annually
Is 1.85 ppm a large number? Let’s look at an analogy of what a population concentration of 1.85 parts per million really represents. If the population of Wyoming (544,270) represented all the molecules in the atmosphere, there would be only one methane molecule in the entire state. At 1.85 ppm, there would be fifteen methane molecules in New York City, out of population eight million. There would be on average zero in Nunavut, Canada.
I wonder how much methane Taco Bell indirectly generates per annum? I also wonder why so many Arctic/Greenland studies include only the years 2003-2008. Perhaps they are only interested in reporting data from unusually warm years in the Arctic?
Speaking of the Arctic. What is up with this?
http://nsidc.org/data/seaice_index/images/daily_images/N_timeseries.png
Methane, The Panic Du Jour
The climate panic headline this week has been that the warming Arctic is burping out dangerous quantities of greenhouse gas Methane.
Published on Friday, March 5, 2010 by Agence France Presse
Huge Methane Leak in Arctic Ocean: Study
WASHINGTON – Methane is leaking into the atmosphere from unstable permafrost in the Arctic Ocean faster than scientists had thought and could worsen global warming, a study said Thursday. From 2003 to 2008, an international research team led by University of Alaska-Fairbanks scientists Natalia Shakhova and Igor Semiletov surveyed the waters of the East Siberian Arctic Shelf, which covers more than 772,200 square miles (two million square kilometers) of seafloor in the Arctic Ocean. “This discovery reveals a large but overlooked source of methane gas escaping from permafrost underwater, rather than on land,” the study said. “More widespread emissions could have dramatic effects on global warming in the future.”
Methane is 30X more potent a greenhouse than CO2, so this sounds very alarming. Or does it? From the New York Times:
Dr. Shakhova said that undersea methane ordinarily undergoes oxidation as it rises to the surface, where it is released as carbon dioxide. But because water over the shelf is at most about 50 meters deep, she said, the gas bubbles to the surface there as methane. As a result, she said, atmospheric levels of methane over the Arctic are 1.85 parts per million, almost three times as high as the global average of 0.6 or 0.7 parts per million.
The first problem with the statement is that it is incorrect. The average global methane concentration is 1.8 ppm, not 0.6 ppm.
http://www.noaanews.noaa.gov/stories2008/images/methanetrend.jpg
The author also says that the Arctic is belching out nearly eight million tons of methane per annum.
She estimated that annual methane emissions from the East Siberian Arctic Shelf total about seven teragrams. (A teragram is 1.1 million tons.)
Sounds like a big number – except that burping/flatulating cattle produce ten times more methane than the Arctic. According to the EPA:
Globally, ruminant livestock produce about 80 million metric tons of methane annually
Is 1.85 ppm a large number? Let’s look at an analogy of what a population concentration of 1.85 parts per million really represents. If the population of Wyoming (544,270) represented all the molecules in the atmosphere, there would be only one methane molecule in the entire state. At 1.85 ppm, there would be fifteen methane molecules in New York City, out of population eight million. There would be on average zero in Nunavut, Canada.
I wonder how much methane Taco Bell indirectly generates per annum? I also wonder why so many Arctic/Greenland studies include only the years 2003-2008. Perhaps they are only interested in reporting data from unusually warm years in the Arctic?
Speaking of the Arctic. What is up with this?
http://nsidc.org/data/seaice_index/images/daily_images/N_timeseries.png