Thursday, November 19, 2009

The Robust Science of Methane

Your robust criticism of Matt Cawood (The Land) and Charles Armstrong (NSW Farmers') for misreading a scientific paper invites a reply, if only to congratulate you for your enthusiasm. I endorse your intention to engage the farm community in the issues, and in this same spirit of bridge-building I offer this defence of Matt and Charles:

While they erred in using the Californian figure for methane as a global figure, their crime pales into nothing when measured against the 2006 FAO report called “Livestock’s Long Shadow”, famous only for being an embarrassment for the organization. The use of the 'data' by Animal Liberation and WWF was scandalous. The University of California study of the U.N.’s data, titled "Clearing the Air: Livestock’s Contribution to Climate Change," politely accuses it of almost being ‘junk science’ in the hands of those ideologically disposed to politicise the methane issue.
“For example, the statement that 18 percent of anthropogenic global GHGs is caused by livestock production and that livestock produces more GHG than transportation (FAO, 2007) is based on inappropriate or inaccurate scaling of predictions,” says lead author of the study, Frank Mitloehner. The sleight-of-hand to reach a point where cattle contributed more emissions than the entire global transport industry involved two subtle shifts of the data: 1. The FAO “Long Shadow” Report included in livestock’s list of liabilities the massive clearance of forest in South America and elsewhere to graze cattle. The UCal report notes that the chief source of greenhouse gases from livestock production isn’t the animals themselves but deforestation for livestock production. 2. At the same time, when making the comparison with the transport sector, the FAO report did not take such a whole of lifecycle approach, thus lightening the sector’s load. And making methane look worse.
So, the argument that “methane is such a big problem, we can’t let farmers get off scot free” loses momentum. Where does it represent 18% and compared to what? The truth is that nowhere does it represent 18%. The authors of the FAO report were too quick on the trigger to be credible.
An even bigger credibility problem for those who promote the “Big Methane Problem” syndrome: Cattle may not cause methane increases at all, according to research sponsored by the FAO. “Since 1999 atmospheric methane concentrations have levelled off while the world population of ruminants has increased at an accelerated rate,” it reports at “Prior to 1999, world ruminant populations were increasing at the rate of 9.15 million head/year but since 1999 this rate has increased to 16.96 million head/year. Prior to 1999 there was a strong relationship between change in atmospheric methane concentrations and the world ruminant populations. However, since 1999 this strong relation has disappeared.” Since 1999, there was an atmospheric increase of 0.3 ppb methane/year. This contrasts with the 10.8 ppb/year for the previous time period of 1979 to 1999.
How can this be? No one can explain it. Even Australia’s most senior scientists say “It might be this… It might be that…” What is a farmer to think? How credible does this tangled story sound? "Trust us, we're scientists."
Science claims to be able to tell us what our global methane emissions and our national emissions are, but not our herd emissions. Why? How did they get the global number? By adding up the national numbers? How did they get the national numbers? They have no herd numbers. They estimated it? Based on what? Whose Science? What was the predisposition of the individual scientist who did the estimation? In a report from the very frontiers of methane measurement science, Dr Ed Charmley (CSIRO Livestock Industries) has developed a laser that he shoots over the top of a herd. But he despairs of 100% accuracy. “You’re never going to have a definitive answer, but compared to the way methane is estimated currently, we’re looking for more elegance in the way it’s done.”

More elegance. More Dinkum Science.
Australian farmers won't shirk their duty. But give us something we can believe in.

No comments: