From 2005 onwards, satellite-based observations found elevated levels of methane (CH₄) in the atmosphere above evergreen forests in tropical regions.

Methane is a very potent greenhouse gas, and intense research effort went into trying to discover the source. Because methane degrades relatively rapidly* in the atmosphere, it's clear that there must be some local production mechanism.

It was suggested that the methane might be being produced by some process involving the plants themselves. (Other known sources for methane production are all anaerobic - i.e. do not occur in the presence of oxygen).

Various explanations were proposed, and many lab tests were carried out on plant specimens - some showing positive results for methane production (in the presence of UV light), others failing to find any.

To date, there is still no agreed explanation for the findings.

The scale of the methane production is also disputed. Some research groups asserting that the effect accounts for as much as 30% of methane in the atmosphere - others claiming the entire subject is the result of erroneous measurements.

See : Wikipedia

Notes :

1) Atmospheric methane typically degrades in about 9 - 12 years, producing another greenhouse gas, CO₂ in the process.

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

Also 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…