Kiwi cows – climate change champions!

Professor Myles Allen of Oxford University, and a lead author of the October 2018 IPCC report, spoke to a capacity crowd in the Whangarei library tonight.


Professor Myles Allen

His core message for New Zealand was about methane. He debunked prevailing assessments that linked methane CO2 equivalents (e), claiming that it has a significantly different action to CO2.

Here are the consequences for New Zealand extracted from the slide below.

How different emissions contribute to future warming

  • Combined NZ CO2 and N20 emissions in 2020 = about 50 MtCO2-e/year.
  • Reduce CO2 and N20 to net zero  by 2050 in a straight line = 750 MtCO2-e total future emissions by 2050.
  • Not reducing NZ’s methane emissions by 10% by 2050
    = extra 4 MtCO2-e/year of methane in 2050 if emissions stable
    = warming impact of an extra 840 MtCO2-e by 2050.
  • Reducing NZ’s methane emissions by 19% by 2050
    = cooling equal to the removal of 750 MtCO2-e by 2050
  • Climate neutral NZ


Thus net zero carbon in New Zealand can be achieved with a 19% reduction in methane over 30 years alongside reducing CO2 and N20 emissions! That’s 0.63% a year. This could happen through herd reduction, but doesn’t need to, as effective stock and pasture management can easily achieve it. Ben Smith was in the room, and he claims his company has achieved a 30% reduction.

This flies in the face of the popular assertion that we need to reduce our national herd. We certainly need to reduce the environmental impact of the herd, but that can be achieved with regenerative farming practices that focus on soil and ecosystem health. Methane reduction and carbon sequestration are complimentary, as soils rich in carbon create better hydrated pasture, which according to Dr Walter Jenhe, increases transpiration and therefore oxidation of methane (see more about methane in this post).

The challenge is to translate his science into policy that is globally accepted.

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