Hi again! Caroline here, and welcome back to Food for Thought. This is part 2, where we'll be talking about methane and emissions while trying to answer the questions of just how serious are cow burps and who's the real bad guy? QUICK NOTE: If you haven't read part one of this series, start here. This series is designed to be cumulative.
So to start off with, let's talk about methane. Methane is a type of greenhouse gas. Greenhouse gases (GHG's) trap heat in the atmosphere and keep our planet warm. There are natural sources of greenhouse gases (these are called biogenic) and ones that are caused by humans (anthropogenic - the ones that cause all the problems).
Methane (CH4) and carbon dioxide (CO2), are important to understand and differentiate. Methane can be derived from human activities like coal mining and waste decomposing in landfills, but it can also come from natural sources, such as wetlands, termite mounds, and ruminants. Carbon dioxide on the other hand is emitted naturally as part of the carbon cycle, however the largest amount comes from human activity, most notably the burning of fossil fuels.
Methane and carbon dioxide differ widely when it comes to their life span as well as potency. According to UC Davis, while Methane has a warming potency more than 28 times that of CO2, it only stays in our atmosphere for about 12 years and eventually returns to the atmosphere as recycled carbon. Carbon dioxide is less potent but stays in the atmosphere for hundreds or even thousands of years.
Methane is considered a "flow" gas, while CO2 is a "stock" gas. The difference is important. Because methane has such a short lifespan, if a stable amount of methane is emitted over, say, 12 years, that means it is being created and destroyed at the same rate. It would not contribute to *additional* warming after those first 12 years. This is why it's important to decrease methane emissions - because it would have a rapid, nearly immediate decrease in planetary warming compared to CO2. As a stock gas, CO2, once emitted, stays in the atmosphere for thousands of years. For our purposes it is practically permanent, and there is little we can do about CO2 that has already been emitted. (Although...I think restoring soil carbon is a great start. But anyway.)
Let’s take a look at greenhouse gas emissions overall. You might be wondering which sectors in the US contribute the most, and you might be thinking that agriculture has to be up near the top. (I know I did before I looked it up.)
But you can see in this pie chart that it's actually the smallest, with transportation and industry making up the two largest.
Now let's break it down further into JUST methane emissions.
In this pie chart you can see that when it comes to methane, agriculture is responsible for quite a bit. If you combine manure management with enteric fermentation (aka livestock digestion from cows, sheep, pigs, etc) agriculture as a whole is the second largest source at 36%. However, if you combine the different types of fossil fuel emissions, coal mining and natural gas and petroleum systems, you'll see that those account for largest proportion of methane emissions at 38%.
As we'll discuss, methane emissions from livestock and methane emissions from fossil fuels are not created equal. Something else to consider? A new report conducted by the House Committee on Science, Space, and Technology has revealed that "big oil and gas companies have internal data showing that their methane emissions are likely significantly higher than official data reported to the Environmental Protection Agency." This alone is worthy of its own blog post, but what's important to grasp here is that...you guessed it...there's nuance.
But refocusing on agriculture's role in all this, let's go back to enteric fermentation. I mentioned earlier how this refers to livestock digestion, but the major form of it is cow burps, from the beef and dairy industries.
As you remember from the last installment of Food for Thought, cattle are ruminants. And ruminants (cattle, sheep, bison, deer, giraffes, etc) emit methane. There are wild animals emitting methane as well as livestock. And actually, humans and our pets like dogs and cats are also emitting methane, but it is certainly the US's 94 million cattle emitting the most.
But here's something to consider. Cattle are not native to the US, but bison are, and according to estimates there were around 30-75 million bison before the colonists nearly eradicated them. So, let’s say we have twice as many cattle today as there were bison back then. And let’s say cow burps and bison burps are roughly equivalent in terms of methane emission levels. To me, it begs the question: What amount of enteric fermentation emissions is the “natural” biogenic amount in the United States? Does that mean that half the modern amount of methane emissions from cattle just...cancel out? Or should be considered biogenic rather than anthropogenic? Of course, that's a bit overly simplistic as bison and cattle are not a 1:1 comparison, but cattle and bison *on pasture* are pretty darn close.
Since methane emissions from agriculture do account for a large piece of the pie, decreasing them is something scientists are hard at work on. For example, some dairies are implementing "methane digesters" to help prevent gases from escaping and a recent study by research scientists at UC Davis found that adding a bit of seaweed (as seen below) to cattle feed may reduce the amount of methane emissions from cow burps as much as 82%.
One of the hills I will die on is that big corporations need to financially support innovations like this, and help agriculture afford and implement improvements. I'll never forget being at a Sustainability convention and listen to a VP at Starbucks talk about how much they were supporting the dairy industry...with words. Not dollars. Small dairies (the few that remain) cannot afford technology like a methane digester; they are barely scraping by. But they could with a corporate partner. Similarly, many ranchers can not afford an expensive seaweed feed additive to their cow's diets. But if it was subsidized or cost shared in some way, they could.
Photo credit: Allaboutfeed.net
Is your brain melting yet? Hang tight, because now we're going to dive deeper into emissions and try and figure out who the real "bad guys" of emissions are.
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Did you know that grass-finished beef emits more methane than grain-finished?
Did you know that termites have a weirdly high carbon footprint?
Did you know that rice production accounts for 12% of human caused methane?
Did you know that citing statistics without any context is really unhelpful?
I’ve sat around so many dinner tables and heard how meat eating is to blame for climate change. The rancher in me needed to investigate this further, so naturally I got to googling. I found that while the headlines were focused on cow farts - or more accurately, cow burps, like we talked about earlier, the data is really pointing to energy, transportation, and industry. Let me show you.
This is *global* greenhouse gas emissions by sector. And quick note: global stats on emissions paint a bleaker picture for agriculture than US stats, and that's largely because the US is more efficient at raising livestock and crops than other parts of the world. But back to this chart - kind of wild right? Look at how big of a piece of the pie that all the different facets of energy transport takes up! I could go on, but I think it's pretty safe to say that it's just not cow burps that are responsible for greenhouse gas emissions.
Here's another interesting graph. This shows total greenhouse gas emissions broken down by country. Except you'll notice that amongst the countries, there's an outlier- food wastage. It's staggering to even wrap my brain around, but you can see that if food waste were a country, it would be the third largest in emissions, right after China and the US. Mind blowing. You can also see here that cereals and grain account are responsible for the two largest carbon foot prints and food wastage, with meat coming in third. While meat is responsible for quite a bit of carbon emissions up front, very little of it is wasted.
Source: Food and Agriculture Organization of the United Nations (FAO)
Another piece of data I wanted to chase down had to do with global cattle numbers and global methane. If livestock hold such a huge share of responsibility for emissions, these charts should be trending in the same direction, right? Wrong. Did you know that while global cattle numbers have stayed relatively stable at approximately 900 million, global methane keeps going up?
Source: FAS/USDA
Source: FAO
You can also see in the infographic above that despite producing 20% of the world's beef, the US is responsible for about 6% of global emissions from beef. That's because of the efficiency of the beef production system here. Now - a deeper discussion of beef production in the US is the subject of the next Food for Thought, so we won't dig in too deeply yet. But while efficiency is important, it doesn't always mean true sustainability.
Let’s zoom back in to the US again before moving on. Here, methane emissions have actually been decreasing by about 17% since 1990. Meanwhile, cattle numbers have also been going down by 25% since 1975. The US is responsible for raising 20% of the world’s beef however it has significantly lower greenhouse gas emissions compared to Brazil, who is comes in second.
Ok, you ready for more nuance? It’s true that grass fed beef produces more methane than grain finished. But why? The reason is that these cows live longer before harvest (it takes them longer to “finish” aka get fat) so they inevitably will burp more. Furthermore, cows burp more on a 100% grass-fed diet than they do grain. But it's important to keep in mind that that same grass fed beef might be sequestering carbon while on pasture, and offsetting those emissions, while the grain-fed steer might not.
I’ll say it again, it’s not the cow, it’s the HOW. Take White Oak Pastures for example. They conducted a third-party study and confirmed that their operation is carbon negative. Regenerative agriculture, folks!
Credit: White Oak Pastures
Now, this is important: I'm not saying we *shouldn’t* be working hard in agriculture to shrink our carbon and methane emissions. That's why I'm so passionate about responsible grazing and building back topsoil and, hence, carbon in the soil. But at the same time, I think jumping straight to blaming ranchers and meat eaters as "evil" is, at best, unnuanced scapegoating. But if we need a bad guy, I’ve got an idea. Richard Heede, a “carbon accountant,” has spent his life's work finding that just 90 corporations, many of them oil and gas giants, are responsible for most climate change. Am I oversimplifying things? Well, so are people that blame global warming on cow burps.
At this point you might be wondering why I haven’t talked about feedlots, or water, or other beef hot topics beef. Don't worry, we'll be covering all of that coming up. Stay tuned!
Caroline
