New methane metric: the cattle is a climate ally

Oxford professor Myles Allen is the planet's leading methane climate scientist. His scientific contributions on the functioning of this gas are recognized by the global scientific elite, including the IPCC (AR6, chapter 7).

Last week, he participated in the Josué de Castro International Conference on Food Security, in a panel entitled the social role of meat - but also debating the "climatic" role of livestock farming.

The focus of his presentation: the need to review methane calculation standards and the treatment of livestock in the climate agenda.

For Allen, the methane calculation metrics and their applications to assess meat sustainability are “outdated” and “misguided”.

First, we treat methane as if it were CO2. Each additional molecule of CO2 emitted causes the atmosphere to heat “basically forever.” Methane, in turn, survives for 10-12 years in the atmosphere. After this period, it withdraws from the air, eliminating its environmental impact. The GWP100, the most influential metric for calculating methane warming, does not correctly recognize this subtraction.

Second, we treat the cattle as if it were an oil company. Once the oil is extracted from the ground, the methane is eliminated. After 10-12 years, the methane breaks down into CO2, and remains in the atmosphere for 100-1000 years. The cattle, in turn, is a filter: it consumes the CO2, captured by photosynthesis from the pasture, which will be digested producing methane, which will soon return to the same CO2 molecule that resided in the atmosphere before.

Put the variables together and we have an equation that is very different from the popularized image of livestock farming. Instead of being a fundamental problem for climate warming, livestock farming can, with productivity gains, be a fundamental agent for "cooling" the atmosphere.

How to fix the problem?

Allen presents two proposals.

The first: Brazil should, at COP30, request changes to the "outdated" methane measurement standards that harm livestock farming and still dominate IPCC guidance, due to lobbying or prejudice against meat.

The second: create a payment service for livestock farmers for actions that reduce methane emissions. If stopping production to plant forests "generates credit", increasing livestock productivity should also generate credit, as the climate effect is equivalent.

None of this, however, will move forward without an important preliminary: it is necessary to overcome the strident catastrophism that still predominates in the debate on livestock and meat; and, in its place, position the rigor and credibility of the best science.

Daniel Vargas, Professor da FGV EESP e da FGV Direito Rio