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…)
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.