Methane is a recycled form of carbon

Other scientists form a similar opinion about the outdated form of methane rating. Prof. Bates says that prof. Frank Mithloehner of the University of California, Davis, also supports the use of GWP*.

This researcher emphasized that the CO2 that is a result of the decay of methane from ruminants is not new in the atmosphere, but only gets recycled. The carbon was stored in plants which were then eaten by ruminants.
Mithloehner then followed up by saying that by referencing the GWP* standards, methane produced by ruminants should be treated differently than methane from fossil fuels.

However, the latter can also be percieved as part of a recycling system, it's thousands of times slower than the agricultural system and contributes to the release of extra carbon in the atmosphere.

Another scientist, prof William van Wijngaarden from Canada, confirmed that methane does have a high initial potential compared to CO2 on tonne-per-tonne basis, the slow rate of the world-wide increase of methane in the atmosphere is so small that the yearly contribution to global warmin is only a tenth of that of CO2.

If we only account for methane produced by ruminants, then the global warming factor reduces to 1/77th of that of CO2, causing it to be almost irrelevant in terms of global warming.

Time for change

These are very different scientific findings then compared to that in the previous research.
Prof Bates states that this recent scientific progression in the area of climate change with methane now proves sufficient to be used. He concludes that the government should make an end to using the outdated GWP-system in national methane-bookkeeping, due to the fact that following this system will create unjustified material damage in Irish agriculture.

CO2 equivalent

The fact that different gasses have a different global warming potential, makes the development of a common unit - CO2 equivalent or CO2-e neccessary to add up.

Carbondioxide (CO2) gets a rate of global warming (GWP) of 1, while nitrous oxide (N2O) gets a rate of 265 to 298 times that of CO2 over a period of 100 years.
This article shows the situation with methane (CH4) is way more complex and doest not qualify for a single coefficient.

Since recent the used coefficient for methane (CH4) was 28 times that of CO2, but recent studies show that this could be a negative value in the situation where the speed of biogenic methane reduces with time.

Although the usage of the CO2 equivalent can continue, the contribution of methane should be treated differently.


Irish Farmers Journal

Ruminant methane decision pending – GWP100 versus GWPstar