Conservation Comment: Climate change is about science, not politics

We need to act now when it comes to climate change, writes Brit Bunkley. Photo / 123rf

OPINION:

Ruminant emissions and their “excessive” land use make up a significant portion of global greenhouse emissions. Guardian columnist George Monbiot suggests that “pasture-fed beef and lamb have by far the worst impacts, three or four times worse … than beef raised intensively on grain. Harmful as this is … raising a kilogram of beef protein releases 113 times more greenhouse gases than growing a kilogram of pea protein”.

Of course, we have to eat. But the meat and milk from animals fed entirely by grazing provide just 1 per cent of the world’s protein while using more than three-quarters of the world’s habitable land, according to Oxford’s Our World In Data. This is land that could be wilded for carbon sequestering or producing plant-based food.

This is a very difficult proposition since agriculture, our primary export industry, produces up to nearly half of New Zealand’s emissions. The OECD reported in 2017 that livestock agriculture is a major factor in New Zealand, producing the “second-highest level of emissions per GDP unit in the OECD and the fifth-highest emissions per capita”.

But land use is only part of the equation. Livestock farming produces 50 per cent of our nitrous oxide, which has 298 times the warming impact of CO2. Methane burped by cattle and sheep produces up to 120 times more warming power than 1 tonne of CO2.

Yet, a new metric, “global warming potential star” (GWP*), has been developed by Oxford University scientists. Depending on how it is viewed, methane gets more credit for being a short-lived pollutant. It has been suggested that the climate damage of methane had previously been “overstated by three to four times”.

On the other hand, environmental scientist Matthew Hayek stated that “industry influences the type of questions you’re going to ask”. Scientists may frame their research questions to be more favourable to industry.

The new GWP* also cuts both ways. Duke University climate scientist Drew Shindell proposes that the old metric severely underestimated its heating power in the short-term: “With this rise has come significant warming over and above that caused by CO2.”

Almost as soon as you stop releasing the gas, its contribution to global heating stops. Effective action against climate collapse needs to be urgent and fast to prevent temperatures and Earth systems from crossing tipping points. Therefore, cutting methane is not less important, but more important.

With the early signs of climate change bearing down on us, we need to get the science right and not turn it into a political football. The political right, while claiming that our small population justifies their inaction, has been bullying the Government into backing down on methane emission controls. We need to pull our weight and do the right thing. The climate is not waiting.