By Paul Homewood
I was sent this article two years ago, and it is relevant to the debate about the impact of agriculture on GHGs:
The way the public and media perceive the environmental impact of livestock farming can and should change. New research from the University of Oxford and the University of California, Davis has recently debunked some of the oldest and most important myths surrounding animal farming. But can this breakthrough fix the livestock industry’s bad reputation?
The current livestock farming narrative states that ruminants (eg, beef cattle, dairy cows, etc.) produce methane. Methane is a strong greenhouse gas. So livestock is bad for the environment.
In an important presentation for Alltech ONE virtual experienceDr. Frank Mitloehner, professor at the University of California, Davis and air quality expert, has boldly proclaimed a path for livestock farming to become climate-neutral.
Yes, “you heard me right – climate neutral,” says Dr. Mitloehner. He said he wanted, “to take us to a place where we have the effects of livestock farming without being detrimental to our climate.”
3 myths about the environmental impact of animal agriculture debunked
Myth #1: Methane (the most common greenhouse gas, or GHG, in agriculture) acts like other greenhouse gases in the environment.
Reality: The three main greenhouse gases, carbon dioxide, methane, and nitrous oxide, all affect the environment in wildly different ways, especially with regard to their origin, their lifespan in the atmosphere, and their ability to heat up. up globally.
Carbon dioxide and nitrous oxide are called “Storage gas.” Stored gases are long-lived gases that, once released, continue to accumulate in the atmosphere. For example, carbon dioxide has an estimated lifetime in the atmosphere of 1,000 years, which means that carbon dioxide released since 1020 is likely still in the atmosphere today. On the other hand, methane is a “gas flow. “Flow gas is a gas that is short-lived and is removed from the atmosphere at a faster rate. The lifespan of atmospheric methane is about 10 years. This means that a gas stream such as methane will impact the environment in an almost 100 times shorter time than stored CO2.
What caused these gases in the first place? Carbon dioxide gas created by burning fossil fuels. Fossil fuels are used as an energy source to power most homes, vehicles and industry globally. As the chart below depicts, Dr. Mitloehner refers to stored gases like carbon dioxide as a “one-way street” because they only accumulate in the environment over time due to their long lifespan.
Methane It can be produced by different methods, but most commonly, it is produced through rumination in beef and dairy farming (i.e. belching). As a short-lived gas stream, “The only time you actually add new methane to the atmosphere with your livestock is during The first 10 years of its existence or if you increase your herd size,” explains Dr. Mitloehner. The level of methane does not increase if the herd size is constant because the methane is being broken down at the same rate that it is being produced.
“What I’m saying here isn’t at all (is) unimportant methane,” he continued. “While that methane is in the atmosphere, it is trapping heat, it is a strong greenhouse gas. But the real question is, will our herds produce more methane, that is, extra carbon in the atmosphere, leading to further warming? And the answer to that question is no. As long as we have continuous herds or even herds reduction, we won’t add more methane, and therefore not add to warming. And what I just told you is a complete change of story around livestock. “
In addition, carbon dioxide is created from the extraction of fossil fuels that are millions of years old and trapped under the Earth’s surface.
“These long-standing climate pollutants are just being released,” said Dr Mitloehner. “They get into the atmosphere, but there’s no real sink to it in a major way.”
This demonstrates that carbon dioxide and methane are very different gases (stock versus runoff) and have very different lifespans in the environment (1,000 years versus 10 years), but with global warming potential. What about their needs?
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Myth #2: The current method for assessing the global warming potential (GWP100) of greenhouse gases correctly accounts for all the important variables.
Reality: Original method to calculate GWP100 misrepresentation of the effects of short-term flux gases, such as methane, on future warming. The new “GWP*” is an improved and more representative measurement.
The original GWP100 measures introduced by the Kyoto Protocol nearly 30 years ago marked a very positive step forward in assessing global warming. The original documents included many footnotes and warnings to account for the change and unknown values. Dr Mitloehner said: “But the caption was cut off, and people ran after (it). “And in my opinion, it’s a very dangerous situation that has really gotten the livestock industry in a lot of trouble, actually, quite frankly.”
The current GWP100 measurement generates an overestimation of methane’s contributions to global warming. In summary, currently, GWP100 measurements are all standardized to one billion tons of carbon dioxide equivalent. So all non-carbon dioxide emissions are converted by multiplying each gas’s emissions by its 100-year global warming potential value. Methane has a GWP100 value of 28, which means it is 28 times more powerful than atmospheric carbon dioxide.
Unfortunately, this type of calculation completely ignores the fact that flow gases, such as methane, are destroyed after about 10 years and will not continue for the entire 100-year period as described in the GWP100 formula. . Additionally, it underestimates the impact that stored gases, like carbon dioxide, will have on the environment for 1,000 years.
Dr Mitloehner cites Dr Myles Allen from the University of Oxford as a pioneer of a new calculation called “GWP *”. The new GWP* calculation is better for both the gas intensity and the lifetime of the atmospheric gas in its measurements of global warming. This is a new story to explain global warming emissions and Dr Mitloehner said, “you will see it gaining momentum, and it will soon become the new reality”.
Myth #3: To keep up with growing demand and a growing global population, the United States has continued to increase its beef and dairy populations, thereby increasing methane emissions.
Reality: The United States reached its peak in beef and dairy cattle populations in the 1970s and has been decreasing cattle numbers every decade since, resulting in a total decrease of 50 million heads.
Over the past half century, the United States has made tremendous progress to improve efficiency and increase productivity while reducing total beef and dairy cattle populations. In 1950, for example, the US dairy herd peaked at 25 million heads. Today, The dairy herd is about 9 million heads, but the milk production is 60% more. – that’s significantly more milk with 14 million fewer cows!
While livestock numbers continue to increase in countries like India and China, this means that the United States has not increased its methane production – thus not increasing the GHG contribution from livestock – in five decades. via.
https://www.alltech.com/blog/3-myths-debunked-animal-agosystemures-real-impact-enosystem
The first myth of this article really gets to the heart of the matter. As Dr Mitloehner explains, global atmospheric methane stocks will not increase unless livestock herds increase around the world. And even if you get rid of all livestock, the methane reduction is only worth ten years.
Of course there are other factors that are not taken into account here. If we abolish all livestock, how do we replace that food? All types of food production, whether arable or not, are associated with GHG emissions, especially in the use of fertilizers, which would certainly increase without manure.
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