Methane is a flow gas, with an atmospheric lifespan of around 12 years. New sources of methane will add warming to our planet for 12 years, but if the emission rate remains near constant over time, methane is destroyed at roughly the same rate that it is produced.
It breaks down into its component molecules, including carbon dioxide, which can then be removed from the atmosphere and recycled through the biogenic carbon cycle. Some sources point to ruminant livestock like cattle and sheep as carbon-heavy food sources due to the methane they emit and the resources needed to raise them.
But if Americans did stop eating meat, what kind of effect would that have on climate change? According to Dr. Mitloehner describes. On the other hand, eating meat places us within the biogenic carbon cycle — and allows us to take advantage of land that would otherwise go unused.
The biogenic carbon cycle allows livestock to turn indigestible plants and otherwise unusable land into an important food source for humans. Smart agricultural practices can help cut down on the impact that raising ruminant livestock can have on greenhouse gas emissions. The pattern is clear — and the opportunities are enormous. With a deeper understanding of the physical scientific basis of climate change and the role technology can play in helping to mitigate it, farmers can proactively contribute to this effort.
There are a variety of ways farmers can decrease the amount of methane produced by their livestock, including:. By continuing to make smart, efficient, environmentally friendly decisions when it comes to the way livestock is raised, the agricultural industry has the opportunity to do more than decrease emissions — it can help combat climate change on a global scale. And by choosing to support those farmers, everyday consumers can contribute to that effort. Farmers and ranchers need sound information and accessible, science-based solutions that benefit their livestock and the environment.
Those solutions need to be readily available to farmers across the globe, with a shared network of information on best practices and ways to adapt them to different countries, cultures and climates.
Is the warming effect of all greenhouse gases GHGs the same? In addition, cows in tropical regions produce less milk and meat, so it takes them longer to get to market. That may be critical going forward as demand for meat is rising in developing countries.
Kebreab, Mitloehner and other UC Davis scientists are looking for ways to make cows more sustainable and less gassy. One way to do that is to make their high-fiber diet easier to digest, so scientists often turn to feed supplements for this purpose. It sounds simple, but finding an affordable and nutritious additive has proved difficult. However, Kebreab has succeeded in finding such a supplement by feeding dairy cattle a plant way off the trough menu: seaweed.
It could be a relatively inexpensive solution for reducing emissions. This type of red seaweed, called Asparagopsis taxiformis , has one big drawback: a wild harvest is unlikely to provide enough of a supply for broad adoption.
Other scientists are looking for ways to grow it to scale, and Kebreab remains hopeful that feed additives hold the most promise. Besides emitting greenhouse gases, another common criticism of beef production is that cows take up nearly half the land in the United States. Overgrazing those lands can degrade soil health and biodiversity.
Yet researchers argue that, managed correctly, cows help restore healthy soils, conserve sensitive species and enhance overall ecological function. Proper cattle grazing management can even help mitigate climate change. However, scientists have also started to look at ways that farmers can reduce the carbon footprint of beef before it reaches the plate. Carbon Brief visited Rothamsted Research — a unique experimental farm in Devon — to find out more about how beef farmers could cut their contribution to climate change.
Cows are ruminants, meaning that their stomachs contain specialised bacteria capable of digesting tough and fibrous material such as grass. The digestive process causes cows to belch out methane — a greenhouse gas that is around 25 times more potent at trapping heat than CO2. The removal of trees causes CO2 to be released into the atmosphere.
In addition, grazing cattle need plentiful supplies of grass — meaning farmers often use nitrogen fertiliser on their fields to stimulate plant growth.
The production of nitrogen fertiliser causes the release of CO2 and the potent greenhouse gas nitrous oxide N2O. In total, emissions from livestock account for around Carbon footprints of meat production. Chart by Rosamund Pearce. Data source: FAO. In Devon, a county in south-west England, agricultural scientists at Rothamsted Research farm are exploring various avenues that could be taken to reduce this figure.
The inputs include cow feed, while outputs include manure, the amount of weight gained by the animals and the run-off of nutrients, such as nitrogen.
This close monitoring allows the researchers to keep a record of the carbon footprint of each animal reared on the farm, explains Graham McAuliffe , a PhD student at the farm and the University of Bristol. He tells Carbon Brief:. The plots represent three typical farming systems used for beef production, McAuliffe says:.
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