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Wikenigma - an Encyclopedia of Unknowns Wikenigma - an Encyclopedia of the Unknown

Methane hydrates

Mehane hydrates - a.k.a. methane clathrates - are an important factor in total global methane levels (see Global Atmospheric Methane Cycleplugin-autotooltip__plain plugin-autotooltip_bigGlobal Atmospheric Methane Cycle

Methane is roughly 80 times more potent as a Greenhouse Gas (GG) than CO2. Over the last 30 years, the measured levels in the atmosphere have been steadily rising, - maintaining a clearly-defined seasonal cycle.

"Methane is an important greenhouse gas, responsible for about 20% of the warming induced by long-lived greenhouse gases since pre-industrial times. By reacting with hydroxyl radicals, methane reduces the oxidizing capacity of the atmosphere and genera…
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They are commonly found in permafrost deposits and on (and under) the sea floor, being a frozen, naturally‐occurring, and highly‐concentrated form of methane linked with water molecules.

For stability, they require low temperatures (typically < 15 °C) and moderately high pressures. When warmed, the trapped methane is released and ultimately enters the atmosphere - where it is a very potent 'greenhouse' gas. This greenhouse effect leads to higher global temperatures which in turn releases more methane from the hydrates. Thus, they may be a profound factor in the case of positive-feedback 'runaway' global warming.

Some climatologists suggest that runaway methane hydrate release was responsible for the 6°C global temperature increase at the end of the Permian period, a rise which is thought to have caused mass extinctions. [ ref. Trends in Ecology and Evolution, volume 18, issue 7, pp358-365, ]

Although the science behind the storage and release mechanisms is well understood, at present the quantity of naturally stored methane hydrate worldwide is unknown. With expert estimates varying by a factor of more than 30 times.

Current mid-range estimates put the global quantity at around 2.4 trillion tonnes of CH4 [ Source : Review of Geophysics Volume 55, Issue1 ]

Together, these uncertainties make accurate calculations of potential global warming models considerably more problematic.

Note :

As far as Wikenigma has been able to determine, none of the widely used computational Climate Models currently take account of methane levels.


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