CSIRO wants to stop methane emissions: but can they get a grant to stop El Nino’s and cap volcanoes?
Tom Quirk sent me a short note to point out that the big rise in global methane almost certainly was man-made — at least up to the mid 1980′s, but in the last 20 years, the culprit for rising methane appears to be volcanoes and El Ninos. (Note the timing of the spikes in the graph below, as methane pours into the atmosphere some years, but barely changes in most other recent years).
Apparently, the man-made emissions in the 70s and 80s were largely due to leaky pipes in the Soviet Union. Natural gas was dirt cheap up til the mid 1970′s. It was so cheap the Russians didn’t bother to plug those flawed pipes. But as prices rose (and after a big nasty explosion in 1982*) they got serious, fixed the pipes and stopped a lot of the out-gassing.
There are many graphs of atmospheric methane levels showing ominous unnatural rises, but the driving forces become so much clearer if we look closely at the annual change in methane levels. — Jo
The true story of the drivers of methane
Guest Post: Tom Quirk
Methane is a greenhouse gas associated with grazing animals and decaying plant material in swamps and marshes. It has been claimed as a factor contributing to global warming because of an alleged warming effect that is assumed by the IPCC to be 21 times more potent as a greenhouse gas than CO2. However, when calculated correctly[i] on the basis of atomic weight, the actual multiplier is only 7 and, moreover , the concentration of methane in the atmosphere is about 200 times less that that of CO2. Methane in the atmosphere is broken down to CO2 and water over a period averaging some 12 years.
The CO2-equivalent contribution of methane from grazing animals is estimated by various Australian government agencies to be 5 to 10% of national emissions of greenhouse gases. However, these estimates also show no increase in methane from agricultural emissions over the last 20 years.
Recent research shows that the increase in atmospheric methane levels since about 1940 can be explained by the dramatic increase in natural gas (fossil methane) use and leakage from badly managed transmission and distribution systems in the Northern Hemisphere[ii]. With the improvement of these systems leakage has been reduced and there has only been a slight methane increase since 1990 – the level has in fact varied with El Ninos and La Ninas (Figure 2) and methane from grazing animals has not made a measureable contribution.
This graph shows how much methane changes year by year over the last 1,000 years:The next graph shows those same annual changes during just the last century:
Grazing animals only release carbon in methane that has been removed from the atmosphere by the pastures they consume. This process, which recycles carbon over the short term, is carbon neutral as methane is broken down in the atmosphere to form CO2 which is recycled to plants with no net additions to the atmosphere. It is the same as the CO2 closed cycle for human energy needs. Indeed, this same closed cycle is recognised to justify biofuels. Accordingly there is no cause for concern about methane from grazing animals.
The contribution that methane might make to future global temperature changes has been overestimated in computer projections. The IPCC scenarios assume that methane contributions to the atmosphere will continue to grow at rates of 12 parts per billion per year whereas for the last 10 years the rate has been less than 3 parts per billion per year (Figure 2). This extreme assumption of 12 parts per billion per year is used in the CSIRO modelling for sea level changes.
The inclusion of methane in the carbon tax regime and the resources devoted to reducing methane from farming practices, are both inappropriate and unnecessary.
[i] Flood, W. 2011, The methane misconceptions. Energy & Environment 22, 233-239,(2011)
[ii] Quirk, Tom, 2010, Twentieth Century Sources of Methane in the Atmosphere, Energy & Environment · Vol. 21, 251-266, (2010) and International Seminars on Nuclear War and Planetary Emergencies, Erice, 19-24 August 2010, 364-374.
[iii] The early part of the twentieth century shows an annual rise in atmospheric methane until the 1920s and then a gentle decline until the 1940s. Town gas or coal gas was first introduced in the early nineteenth century for street lighting and then for home and industrial use. The gas contained 20% to 30% methane. It was distributed by pipes made in sections from caste iron and later steel and joined by flanges that were bolted together with a gasket to prevent leakage. These were not tight seals and there was an estimated 3% to 5% leakage. The rise in atmosphere methane in the nineteenth and early twentieth century may well come from town gas and the fall after the 1920s is simply a reflection of reduced usage of town gas during the depression of the 1930s.
*PS: Funny story about the big gas explosion in Siberia in 1982 — as the tale of the Farewell Dossier goes, the Russians badly needed software from the West to control its pipe network, so (it’s said) the CIA arranged for them to buy a doctored version as a form of sabotage. Others disagree. There is a lot of interesting discussion out there.