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New model examines the link between climate change and animal agriculture

New model examines the link between climate change and animal agriculture

New model explores link between animal agriculture and climate change

A worldwide ban on animal agriculture combined with a shift to a plant based diet would effectively stop the increase in atmospheric greenhouse gases over the next 30 years. This would give humanity more time for ending its dependence upon fossil fuels.

A new model suggests phasing out animal farming over the next 15-years would have the exact same effect as a 68% reduction in carbon dioxide emissions through 2100.(Image credit: Getty Images).

“We wanted to answer a very simple question: What would be the impact of a global phase-out of animal agriculture on atmospheric greenhouse gases and their global-heating impact?” said Patrick BrownProfessor Emeritus in the department biochemistry at Stanford University. Brown co-authored this paper with Michael Eisen (UC Berkeley professor of genetics & development).

Based on the model, published by the open-access journal PLoS ClimateA 68 percent reduction in carbon dioxide emissions by the year 2100 would result from the phasing-out of animal agriculture over the next fifteen years. This would achieve 52 percent of net emission reductions required to limit global temperature rise to 2 degrees Celsius above the preindustrial level, which scientists believe is the minimum threshold necessary to avoid catastrophic climate change.

The changes would stem, the authors say, from the spontaneous decay of the potent greenhouse gases methane and nitrous oxide, and the recovery of biomass in natural ecosystems on the more than 80 percent of humanity’s land footprint currently devoted to livestock.

“Reducing or eliminating animal agriculture should be at the top of the list of potential climate solutions,” Brown said. “I’m hoping that others, including entrepreneurs, scientists and global policymakers, will recognize that this is our best and most immediate chance to reverse the trajectory of climate change, and seize the opportunity.”

Brown is also founder and CEO at Impossible Foods. The company develops alternatives for animals in food production. Eisen serves as an advisor to the company. Both Eisen and Brown will benefit financially from the decrease in animal agriculture.

Unlock negative emissions

Brown and Eisen were not the first to recognize that emissions from animal farming continue to contribute to global warming. But what has not been recognized before, they say, is the much more impactful “climate opportunity cost” – the potential to unlock negativeEliminating livestock from the equation will reduce emissions.

“As the methane and nitrous oxide emissions from livestock diminish, atmospheric levels of those potent greenhouse gases will actually drop dramatically within decades,” Brown said. “And the CO2 that was released into the atmosphere when forests and wild prairies were replaced by feed crops and grazing lands can be converted back into biomass as livestock are phased out and the forests and prairies recover.”

Brown and Eisen used publicly available data about livestock production, livestock-linked emission and biomass recovery capacity on land currently used for livestock support to predict how phasing out global animal agriculture production would affect net anthropogenic or human-caused emissions starting at 2019. They then used a simple climate modeling to predict how these changes might affect the evolution and warming of the atmosphere for the rest of this century.

They looked at four possible dietary options: an immediate replacement for all animal agriculture with a diet that is plant-only; a gradual, but more realistic, transition over 15 years to a global, plant-only diet; and versions in which only beef was replaced by plant-only products.

The scientists assumed that non-agricultural emission would remain constant for each scenario and that land previously used for livestock production would become grasslands, prairies and forests that absorb atmospheric carbon dioxide.

“The combined effect is both astoundingly large, and – equally important – fast, with much of the benefit realized by 2050,” Brown said. “If animal agriculture were phased out over 15 years and all other greenhouse-gas emissions were to continue unabated, the phase-out would create a 30-year pause in net greenhouse gas emissions and offset almost 70 percent of the heating effect of those emissions through the end of the century.”

According to the model, the complete elimination of animal-based farming was projected to have the greatest impact. However, 90 percent of emission reductions could only be achieved by replacing ruminants such cattle and sheep.

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Young people take part in a climate change rally in Washington Sept. 20, 2019. (CNS/Reuters/Erin Scott)

While their paper does not explore the particulars of what a global phaseout of animal agriculture would entail, the authors acknowledge that “the economic and social impacts of a global transition to a plant-based diet would be acute in many regions and locales” and that “it is likely that substantial global investment will be required to ensure that people who currently making a living from animal agriculture do not suffer when it is reduced or replaced.”

But, they write, “in both cases, these investments must be compared to the economic and humanitarian disruptions of significant global warming.”

Change your attitude

Many will be shocked that billions can be persuaded to change to a plant-only diet within 15 year. Eisen counters this argument by pointing out that other revolutions occurred in a shorter time. “We went from having no cellphones to cellphones being ubiquitous in less time than that. Electricity, cars, solar panels – all became common in a relatively short period of time,” Eisen said.

Brown also said that attitudes to food are still changing. “Five hundred years ago, nobody in Italy had ever seen a tomato. Sixty years ago, no one in China had ever drank a Coke. Mutton was once the most popular meat in America,” he said. “People around the world readily adopt new foods, especially if they are delicious, nutritious, convenient and affordable.”

All of the data used by the scientists, as well their calculations, have been made publicly available to allow others to make their own decisions.

“The great thing about science is that, in the end, it all comes down to whether the conclusions are supported by the evidence,” Brown said. “And in this case, they are.”

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