Advocating for the GWP* metric

A109 Light Utility Helicopter flight with mayor Gisborne City from the air in November 2023.

Opinion

The outgoing, council-going Federated Farmers branch president and vice-president have both now responded to the editorial last Thursday which questioned what science it was that the farmer lobby group was basing its position around biogenic methane emissions on.

In a column on Saturday, Sandra Faulkner claimed that working hard towards a 10 percent methane reduction from livestock by 2050 would mean the sector was committing to do more in the fight against climate change than the rest of New Zealand “from the get-go”.

It seems the Fed has a different view of what “no additional warming” means to the PCE (Parliamentary Commissioner for the Environment), as the modelling he commissioned has biogenic methane reduction requirements ramping up if the world is on track to limit warming to a 1.5C average global rise.

Mrs Faulkner outlined some of the science the Fed was going off then said “many commentators . . . miss (the point) that biogenic methane is not a major contributor in New Zealand or internationally”, without explaining why the science they prefer sees much smaller reductions by 2050 than the 24-47 percent target in the Zero Carbon Bill.

Helpfully Neil Henderson has described the nub of the different perspectives in his column today, with the Fed taking its position from science papers on a new metric for methane emissions called GWP*, rather than the GWP100 (global warming potential over 100 years) metric behind the 24-47 percent target in the Zero Carbon Bill.

In his report Farms, Forests and Fossil Fuels, the PCE says the merits and shortcomings of different metrics for greenhouse gases “remain the subject of intense ongoing debate”. While GWP* provided “a closer correspondence between emissions, radiative forcing and global temperature impacts”, it was likely the GWP100 metric would continue be used for international reporting and accounting “for the foreseeable future”.

So when the Fed suggests “the science” shows farming is not the climate change problem it is made out to be, it should work a lot harder to try to convince us and, more importantly, our politicians and the soon-to-be-established independent Climate Change Commission.

As to the “how dare you” column today, there was no effort from the Fed to “highlight inconsistencies”, just a claim that science was on its side with no explanation. To question the evidence base for the Fed’s position is to encourage debate on this important topic.