Agreed, let’s follow the science . . .
Our columnist today is right to note that there are opportunities to reduce greenhouse gas emissions from cows and sheep, some of which are obstructed by New Zealand's 2003 genetic engineering laws. However, he rather ruins his case by first ascribing the term “speculative theory” to issues around livestock emissions. He is also dangerously wrong to suggest climate action should be deprioritised due to Covid-19 and the need to rebuild our economy.
The greatest threat to existing life on Earth and to humanity's future economic wellbeing remains the risk that we do not collectively and rapidly reduce anthropogenic greenhouse gas emissions.
The science that shows our agriculture industry causes just under 50 percent of the warming attributable to New Zealand emissions (if de-forestation is excluded) is solid; the best information on this comes from the work of Andy Reisinger and Sinead Leahy and can be found here.
It also shows that the 100-year GWP (global warming potential) metric used to compare the climate impacts of different greenhouse gases does a decent job in estimating past and future warming; where this metric falls down, and is the subject of vigorous scientific debate, is under ambitious mitigation scenarios where it can give misleading results with respect to the treatment of methane and carbon dioxide. (That is why it is best to use individual gases when estimating contribution to warming.)
In addition to this science discussion, there is an even more complicated discussion around the link between metrics and emissions reduction targets. It is possible that the outcome of this could in future see New Zealand's target range of a 24 to 47 percent reduction in biogenic methane emissions by 2050 revised downwards.
Regarding opportunities to lower emissions on farms, a year ago the Government's Interim Climate Change Committee raised prohibitive regulations around genetics as a potential obstruction; noting a GM ryegrass developed by AgResearch that could reduce both methane and nitrous oxide emissions from grazing animals, but was having to be tested in the US. In August last year our top scientific body, the Royal Society Te Aparangi, joined calls for an overhaul of our genetic engineering laws after finding an “urgent need” to consider how we might use this contentious and evolving technology in the areas of pest control, primary industries and medicine.
• See also August 12, 2019 editorial here.