250 Methane plumes have been discovered rising from the Arctic Ocean seafloor near west Spitzbergen. The most likely cause is warm water entering the Arctic, destabilizing methane clathrates - methane slush - on the seafloor. The release of methane from clathrates like these has been hypothesized to be the trigger of the Paleocene thermal maximum, the warmest climate since the Mesozoic, the age of the dinosaurs.
By National Oceanography Centre Southampton FishOutofWater
The oceans have been warming rapidly.
Ocean temperatures broke the all time record for warmth for July.
The global ocean surface temperature for July 2009 was the warmest on record, 1.06 degrees F (0.59 degree C) above the 20th century average of 61.5 degrees F (16.4 degrees C). This broke the previous July record set in 1998. The July ocean surface temperature departure of 1.06 degrees F from the long-term average equals last month’s value, which was also a record.
Warming waters are entering the Arctic. The largest sea surface temperature anomalies are in the Arctic. West Spitzbergen is on the far upper right.
By NOAA FishOutofWater
The West Spitzbergen current transports warm Atlantic ocean water into the Arctic ocean. Warmer waters are melting methane clathrates, causing plumes of methane to form offshore of west Spitzbergen
The results indicate that the warming of the northward-flowing West Spitsbergen current by 1° over the last thirty years has caused the release of methane by breaking down methane hydrate in the sediment beneath the seabed.
Professor Tim Minshull, Head of the University of Southampton’s School of Ocean and Earth Science based at the National Oceanography Centre, says: "Our survey was designed to work out how much methane might be released by future ocean warming; we did not expect to discover such strong evidence that this process has already started."
Methane hydrate is an ice-like substance composed of water and methane which is stable in conditions of high pressure and low temperature. At present, methane hydrate is stable at water depths greater than 400 metres in the ocean off Spitsbergen. However, thirty years ago it was stable at water depths as shallow as 360 metres. This is the first time that such behaviour in response to climate change has been observed in the modern period.
Methane clathrates are not just found in the cold deep Arctic. Enormous quantities of methane clathrates are located in the Carolina trough offshore of the Carolinas. Warming oceans could destabilize these huge methane deposits. The quantities of methane stored in clathrates are massive.
The worldwide amounts of carbon bound in gas hydrates is conservatively estimated to total twice the amount of carbon to be found in all known fossil fuels on Earth.
This estimate is made with minimal information from U.S. Geological Survey (USGS) and other studies. Extraction of methane from hydrates could provide an enormous energy and petroleum feedstock resource. Additionally, conventional gas resources appear to be trapped beneath methane hydrate layers in ocean sediments.
Recent mapping conducted by the USGS off North Carolina and South Carolina shows large accumulations of methane hydrates.
A pair of relatively small areas, each about the size of the State of Rhode Island, shows intense concentrations of gas hydrates. USGS scientists estimate that these areas contain more than 1,300 trillion cubic feet of methane gas, an amount representing more than 70 times the 1989 gas consumption of the United States. Some of the gas was formed by bacteria in the sediments, but some may be derived from deep strata of the Carolina Trough. The Carolina Trough is a significant offshore oil and gas frontier area where no wells have been drilled. It is a very large basin, about the size of the State of South Carolina, that has accumulated a great thickness of sediment, perhaps more than 13 kilometers. Salt diapirs, reefs, and faults, in addition to hydrate gas, may provide greater potential for conventional oil and gas traps than is present in other east coast basins.
By USGS FishOutofWater
Global methane levels started rising again in 2007 after a decade of no growth. PDF
Following almost a decade with little change in global atmospheric methane mole fraction, we present measurements from the Advanced Global Atmospheric Gases Experiment (AGAGE) and the Australian Commonwealth Scientific and Industrial Research Organisation (CSIRO) networks that show renewed growth starting near the beginning of 2007.
Arctic warming is also causing carbon rich permafrost to melt, releasing methane to the atmosphere. Huge amounts of carbon are stored in Alaskan and Siberian soils. This methane source may also be contributing to the renewed increase in atmospheric methane levels.
Oil and coal companies are planning a massive lobbying campaign to pressure the Senate to weaken legislation to combat global warming. The companies will argue that global warming is not an immediate problem. However, the discovery of Arctic methane plumes shows otherwise. Immediate action to reduce greenhouse gas emissions is necessary to stop warming oceans from triggering massive releases of methane.
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