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Methane qualification important

Opinion Piece
Letter

Re: An inconvenient truth about livestock, October 26 column.

It took me a while to find the “most recent” “analysis of international experts”, quoted by Sandra Faulkner. It interested me, as I was keen to read how a biogenic pathway of just 7 percent reduction in methane from ruminant animals could achieve net zero carbon emissions by 2050.

The analysis referred to turned out to be a six-page paper commissioned by NZ Meat Industry Assoc. and Dairy Companies Assoc. NZ by a post-graduate student, Nick Leach at Oxford University. He states “for future warming at or below 1.5°C in 2050” “biogenic emissions must reduce by 7 percent below 2017 levels if all other sources of methane reduce to zero by 2050”. The qualification that all other sources of methane must reduce to nil, not mentioned by Sandra, is important, and at present temperatures, impossible to achieve.

Methane is thought to be one of the prime drivers of the Permian mass extinction around 252 million years ago, when an estimated 95 percent of all species were wiped out. It was thought to have been triggered by volcanic action in Siberia warming the shallow Arctic seas and releasing frozen ice containing methane (Encyclopaedia Britannica).

Currently greenhouse gases are warming those same seas and already we have seen methane levels in the atmosphere increase 143 percent, at least partly due to methane plumes in shallow Arctic seas and melting of permafrost on land.

Nasa stated that in 2012 they saw methane levels over swamps in the Arctic 650 times higher than normal. We cannot stop this leakage unless global temperatures are reduced, and this cannot be done unless GHGs not only stop being emitted but are also removed from the atmosphereI agree with the second point made by Sandra Faulkner that planting plantation forest is not going to solve our emissions problem. In fact, the quickest way of reducing emissions is by reducing methane emissions rapidly. The only methane emissions we can control are those caused by leaking natural gas and those produced by animals.

Bill Hambidge