Monday, May 03, 2021

Climate Change: Cut methane now

Farmers are our biggest source of climate pollution, being responsible for 48% of our emissions. Three quarters of their emissions come from methane, caused by burping cows and rotting cowshit. Methane is a powerful greenhouse gas, but short-lived; its impact on global temperature over 20 years is 84 times higher than that of carbon dioxide (its impact when averaged over a century is "just" 28 times higher). Which means that if your goal is to reduce temperature and climate change impacts, the biggest short-term benefits come from cutting methane.

How big are those benefits? On Newsroom, Rod Oram reports on a UNEP/NOAA report which suggests they are staggering:

“The benefits that would come from reducing human-caused methane by 40-45 percent by 2030, a level consistent with the Paris Climate Agreement’s goal to keep warming to 1.5°C, are also quantified and they’re enormous. It would avoid nearly 0.3°C of global warming by the 2040s and, each year from 2030 onward, prevent more than 250,000 premature deaths, more than 750,000 asthma-related hospital visits, more than 70 billion hours of lost labour from extreme heat, and more than 25 million tonnes of crop losses globally.”

The Climate & Clean Air Coalition’s website lays out multiple ways to reduce methane from agriculture, fossil fuels and waste management. In agriculture, for example “rapid and large scale implementation of improved livestock feeding strategies” could reduce methane emissions from animals by 20 percent by 2030; and “full implementation of intermittent aeration of continually flooded rice paddies (known as alternate wetting and drying cultivation) could reduce emission from rice production by over 30 percent.”

In New Zealand, 90% of our methane is agricultural. So we could achieve this cut by halving cow numbers. Farmers act as if this would be apocalyptic, but it would merely reduce them back to where they were thirty years ago, before cows started completely destroying our landscape and our rivers. Which also both shows the clear environmental benefits of doing so, and highlights that we would be reversing an apocalypse, not causing one.

(There would also be economic benefits. According to SwissRe the difference between 1.5 and 3 degrees of warming is 10% of GDP. Which is more than the entire agricultural sector).

This goes well beyond what has been proposed by the Climate Change Commission - a 45% cut in methane is at the upper end of their 2050 target, which they seem to have no intention of meeting (can't offend the farmers after all). But it is what's necessary to mitigate this crisis. And any government which doesn't sign up for it is basicly committed to letting coastal New Zealand drown.