Thursday, 11 April 2024 09:55

We need to do right by GWP*

Written by  Frank Mitloehner
Frank Mitloehner Frank Mitloehner

OPINION: When Myles Allen, a professor of geosystem science at the University of Oxford, talks, I always suggest it’s worth a listen – particularly when he shares information that can help improve sustainability in the cattle sector.

When he spoke at CattleCon in February, his message – although rooted in complex science and based on complicated mathematical calculations – was as plain as day.

“Emissions … from the U.S. livestock sector have caused very little additional warming since 1990,” he said.

Let’s be clear: We need to ensure we do not increase emissions and reduce emissions as we can. We can gain efficiencies by doing so and help meet increasing demand while limiting environmental impact.

So why is animal agriculture – and particularly the beef and dairy sectors – constantly taking it on the chin for methane emissions? Why do people think giving up animal-source foods will save us from climate change?

There isn’t just one reason, but one important reason is that for a long time, we looked at methane through the wrong lens. Our yardstick for measuring the warming potential of greenhouse gases was GWP100, where methane is treated as if – in Allen’s words – “it’s a form of carbon dioxide” that continues to cause warming indefinitely like CO2 does.

In fact, it doesn’t. Unlike carbon dioxide, a stock gas and long-lived climate pollutant, methane is a flow gas with a short lifespan. True, it is more potent than carbon dioxide, but only for the first decade after it’s emitted. Beyond that, it’s broken down into CO2 and water vapor.

To their credit, Allen and his team at Oxford realised the shortcomings of GWP100 and went to work to develop a metric that gives us a far more accurate picture of the warming caused by methane.

However, it is not without controversy. Heated discussions are arising over the fact that GWP* may be scientifically correct but nevertheless unfair to use.

Certain groups dislike GWP* because it shows that animal agriculture can meet demand and significantly reduce its climate impact by committing to strong methane reductions. Other naysayers believe GWP* gives a pass to developed regions with advanced livestock sectors.

For U.S. farmers and ranchers, and many in other developed regions, production isn’t increasing dramatically because population and corresponding demand for animal-source foods are more stable than they are in developing regions. Thus, GWP* can make high emitters look like they aren’t impacting current temperatures, provided they keep their emissions constant.

On the other hand, many developing regions are experiencing significant human population growth and corresponding increases in demand for animal-source foods to better their nutrition.

To score a GWP* win, these producers must cut emissions at the same time they are being asked to produce more animalsource food to feed rapidly growing populations. Their carbon footprint per glass of milk or ounce of meat is higher than it is for U.S. ranchers and farmers. Thus, increasing output in developing regions will come at a higher emissions price relative to regions that have more advanced animal agriculture systems.

No credible sources debate the physics behind GWP*. No one is advocating that we need to stop worrying about methane or give it a pass. We can embrace GWP* and still work on ways to do better by it.

A one-size-fits-all approach isn’t appropriate as we look to tackle the environmental impact of production in a diversity of regions.

A one-size-fits-all approach isn’t appropriate as we look to tackle the environmental impact of production in a diversity of regions.

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