The issues with methane emissions

Livestock methane emissions are contentious as New Zealand looks to how it can do it’s bit in reducing the greenhouse effect and global warming.

With calls to significantly reduce herd sizes there is obviously a lot at stake for farmers – not just their incomes but also their assets.

This information is from Pastoral Farming Climate Research:


Fact sheet Methane emissions, what they say and what is the issue?

With the upcoming Carbon Zero Legislation bound to create discussion about the impact methane emissions have on global warming. This fact sheet is intended to help those involved in that discussion to understand the issue.

It is commonly stated that livestock are responsible for half our greenhouse gas emissions.

This statement is misleading and gives the wrong impression of the extent to which livestock biological emissions are a problem.

Livestock are responsible for half our ‘carbon’ emissions but carbon is not a greenhouse gas. Carbon is a theoretical unit only and is correctly called ‘carbon dioxide equivalent’

All the greenhouse gases are quantified in terms of the amount of warming they are said to cause when compared to CO2. A tonne of methane for example is said to equate to 25 tonnes of CO2 so an emission of 1 tonne of methane is quantified as 25 tonnes of ‘carbon’

The majority of the carbon emissions attributed to livestock are from their methane emissions.

The carbon unit however is highly problematic, as is the concept of trying to equate different greenhouse gases. It is simply not possible because they are too different.

The following statements from well-respected individuals and organsiations demonstrate the problem;

Dr Andy Reisinger Deputy Director NZAGR said of the use of the carbon dioxide equivalent system to quantify methane emissions, that it does not measure the actual warming caused by emissions and ignores the fact that methane does not accumulate in the atmosphere in the same way as CO2. (1)

This is a significant admission. If the carbon unit does not measure the actual warming methane may cause and ignores the fact that methane does not accumulate in the same way CO2 does then it is of no use at all.

ALSO

Motu Economic and Public Policy Research state in their paper Cows, Sheep and Science;

To stabilise the climate, it is necessary to reduce the overall (net) emissions of long-lived climate forcers (CO2) to zero. By contrast, emissions of short-lived climate forcers (methane) do not have to decline to zero; they only have to stop increasing. (2)

AND

Ministry for Environment in its Carbon Zero Consultation document.

Reducing long-lived greenhouse gas emissions (like CO2) to zero and stabilising our short-lived gases, (like methane) which would mean our domestic emissions would not contribute to any further increase in global temperatures. (3)

AND

Dr Jan  Wright (former Parliamentary Commissioner for the Environment)   MANAGING BIOLOGICAL SOURCES AND SINKS IN THE CONTEXT OF NEW ZEALAND’S RESPONSE TO CLIMATE CHANGE

Methane in the atmosphere is short-lived, in contrast with nitrous oxide and carbon dioxide. If the flow of methane into the atmosphere stopped rising, and there were no other greenhouse gas emissions, the temperature of the atmosphere would stabilise in a few decades. (4)

AND

Productivity Commission In its 620 page report Low Emissions Economy methane produced by the belching of sheep and cows – is unsuitable for inclusion in a single-cap ETS due to the difficulty such a scheme would have in driving emissions reductions in a manner that recognises the different atmospheric properties of short and long-lived gases. (5)

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The quotes above demonstrate why it is universally accepted now that long lived gases like CO2 need a different target and policy response to short lived gases like methane.

However it is not possible to state that in order to stabilize the climate carbon emissions sourced from CO2 need to reduce to zero and carbon emissions sourced from methane only have to stop increasing, without concluding carbon is not an equivalence unit. Carbon’s only purpose is to equate the impacts of a number of different greenhouse gases and quantify them using one unit and it fails. One carbon emission is supposed to be the same as another and quite clearly it is not. It is not a credible unit and should not be used.

So the statement that half our greenhouse gas emissions come from livestock is wrong and therefore misleading for two reasons.

1         Carbon is not a greenhouse gas

2         Carbon is not a credible unit and emissions of ‘carbon’ do not reflect the impact an activity may have on global warming.

Putting methane emissions in to perspective’

Livestock emissions of methane when produced from a stable source of livestock do not cause the atmospheric concentration of methane to increase at all.

Most biogenic methane emissions in NZ are produced from a stable source and do not contribute to an increase in atmospheric methane.

Methane emissions in NZ have increased by 4% since 1990. Transport emissions of CO2 have increased by 82.1% since 1990

For full explanation view video The Methane Mistake (7mins)  https://youtu.be/BOJdz_LgDBE

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1 Andy Reisinger, Harry Clark, How much do direct livestock emissions actually contribute to global warming?

2 Motu Economic and Public Policy Research Cows, Sheep and Science 2016 written by Michele Hollis, Cecile de Klein, Dave Frame, Mike Harvey, Martin Manning, Andy Reisinger, Suzi Kerr, Anna Robinson  http://motu-www.motu.org.nz/wpapers/16_17.pdf

3 Ministry for Environment Carbon Zero consultation document http://www.mfe.govt.nz/sites/default/files/media/Consultations/FINAL-%20Zero%20Carbon%20Bill%20-%20Discussion%20Document.pdf

4 Dr Jan Wright Parliamentary Commissioner for the Environment, Climate Change and Agriculture 2016

5 Productivity Commission Low Emissions economy 2018