When you fill your car's tank, you pay a gas tax. Someday, when you fill your belly with cheese, milk, or steak, you might have to pay another type of gas tax — one levied on the methane and nitrous oxide emitted by the cows that produced or became your food.
Bacteria in a cow's gut help digest what the cow eats. During this process, some of the bacteria emit methane, a potent greenhouse gas. Later on, as the cow's manure decomposes, it emits methane and nitrous oxide, another potent greenhouse gas. Consequently, some have suggested that beef, dairy cattle and other livestock should be included in climate change regulations, whether carbon taxes, cap and trade, cap and dividend, or some other approach. Other animals that emit greenhouse gases through digestion or manure decomposition, such as hogs and sheep, could also be subject to such a tax.
According to the Little Falls Times in New York, a report from the Environmental Protection Agency suggested that one policy option would be a tax on facilities with annual emissions of more than 100 tons of greenhouse gas per year. This could cover operations with more than 200 hogs, 50 beef cattle, or 25 dairy cows. For reference, 100 tons is approximately the annual emission of 17 passenger cars or the energy use by 8 average homes, according to the EPA's equivalence calculator. The annual levy would be approximately $20 for each hog, $87.50 per head of cattle, and $175 per dairy cow (the Madison Daily Leader says that these figures are from the American Farm Bureau Federation).
Via The Daily Climate, an aggregator of climate and environmental science news, I ran across comments from a U.S. senator who is not fond of the idea. "This proposal, which will impact New York from one end to the other, is so absurd that we have to put a stake through its heart immediately. Cows can’t change the way they are," Sen. Chuck Schumer (D-NY) told the Little Falls Times.
There are two big problems with that statement. First, even though cows can't change "the way they are," we can change how many of them we raise by adjusting our diets — choosing legumes instead of beef, or goat cheese instead of cows-milk cheese. We can also change how much methane and nitrous oxide reaches the atmosphere by altering manure management practices; for example, by installing methane digesters like those used at Straus Family Creamery in Marin County, CA.
And second, the hard reality is that neither methane nor nitrous oxide can change the way they are, and they will continue to interact with the atmosphere in an undesirable way. (On a pound for pound basis, each of the gases is far more potent than carbon dioxide: the Fourth Assessment Report of the IPCC assigns methane a warming impact 25 times higher than carbon dioxide, and nitrous oxide one that's 298 times higher.)
Unfortunately, it's likely that such climate-change-curbing actions as a "cow tax" will create short-term economic turmoil. Small, independent farm businesses might have to raise their prices and thus suffer reduced sales, potentially driving many into bankruptcy before they could adapt by installing methane capture systems, switching from cows to goats (which emit far less methane), or establishing value-added businesses like farmstead cheese. Therefore, our policymakers need to identify ways to help meat ranchers and dairy farmers adapt to climate-change regulations, perhaps through low-interest loans, direct subsidies, or an adjustment to price-control regulations, as milk prices are highly regulated in the U.S. If a cap-and-trade program is implemented, then money for transitional programs could be raised by auctioning carbon-emission permits (as opposed to some politicians' plans to simply give away the permits based on historical emissions).
After the jump, I'll explore how the emissions are calculated, alternatives to the "cow tax," and what such a tax might actually cost producers and consumers.
Cattle are a significant source of greenhouse gas in the U.S. and around the world. The EPA's Inventory of Greenhouse Gas Emissions and Sinks estimates that the contribution of dairy and beef cattle through digestion (also known as "enteric fermenation") and manure decomposition is about 2% of the total anthropogenic greenhouse gas emissions in the U.S. If we are going to be serious about tackling the climate change problem, then all human-caused sources of greenhouse gases must be included. Unlike burning gasoline or coal, where it's fairly simple to determine the emissions, it won't be easy to count those of cattle, as they probably vary based on feed, climate, genetics, and more. But we can certainly try.
Let's look at the emissions from milk production. A paper in the academic journal Agricultural Systems calculated the GHG emissions associated with milk production in Ireland. They considered "cradle to farm gate" emissions, so they summed the emissions from the animals, feed production, milk collection, and whatever processing occurs before the milk leaves the farm to come up with a figure of 1.5 kg of greenhouse gas per kg of milk. (Note that these emissions are expressed in "CO2 equivalent", or CO2e, which adds up the CO2 emissions, 25 times the methane emissions, 298 times the nitrous oxide emissions and whatever other greenhouse gases are emitted to obtain the amount of CO2 that would have the equivalent climate effect.)
About half of the emissions (49%) are emitted directly from the cows in the form of methane, as a result of their digestion; 11% of the emissions are related to manure management, which means that the direct contribution of the cows is 0.9 kg of CO2e per kg of milk. With annual U.S. milk production of around 85 billion kilograms, that's a lot of greenhouse gas emissions. (The milk production figure is the December 2008 Livestock, Dairy, and Poultry Outlook.)
We also need to look at how the emissions from cows and their manure compares to the rest of the dairy production chain — the diesel fuel to power the trucks, fossil-fuel electricity to pump and chill the milk — because they will almost certainly be included in cap-and-trade or a carbon-tax system. A few months ago I wrote about an academic paper by Christopher L. Weber and H. Scott Matthews from Carnegie Mellon University in which the authors performed a greenhouse gas life-cycle analysis of the average American's diet. One of their estimates was that dairy products average a life-cycle emission of about 4.2 kg CO2e per kg, making the cows' direct contribution to the overall greenhouse gas emission around 20%, a pretty significant number.
Looking at the overall household diet, Weber and Matthews found that methane emissions from cows made up a sizable contribution of the average diet's greenhouse gas emissions. They calculated that average annual household emission was 8.1 metric tons of CO2e, with about 16% of this derived from the methane emitted during production of red meat and dairy.
Alternatives to the 'cow tax'
While it's true that cows can't change the way they are, or their basic biology — at least not yet — we can change what we eat and how cows are raised.
For example, there are numerous protein sources that have far lower greenhouse gas emissions, like chicken, legumes, goats, pork, kangaroo, and so on. As the figure below indicates, when considering the entire supply chain (emissions from feed production, transportation, and the animals' emissions), poultry has a greenhouse-gas emission factor 8 times lower than feedlot beef, while pork's emission factor is about 4.5 times lower (the sources of the data are listed at the end of the post). Legumes are probably even lower. If climate change regulations ignore the far higher greenhouse-gas emissions from cows, it would be a de facto subsidy to the cattle and dairy industries.
Similarly, there are methods to reduce greenhouse-gas emissions from dairy and cattle farms. Lots of research focuses on determining how an animal's feed influences its methane emissions. For example, Living on Earth interviewed a researcher at the Swedish University for Agricultural Sciences whose team is sampling the emissions of dairy cows; researchers have investigated how different feed regimes affect methane emissions from goats; the USDA has an active study underway on emissions from dairy cows; the New Scientist has a summary of other research; and the U.N. report "Livestock's Long Shadow" discusses some other factors, like the importance of considering the greenhouse gases released in producing an alternative animal feed.
I'm sure that many Ethicurean readers are wondering about the grass versus corn equation. The New Scientist article referenced above cites research by Professor Ermias Kebreab and colleagues at the University of Manitoba indicating that cattle fed only grass had higher methane emissions than cattle fed a mixture of corn and grass. That's interesting, but it doesn't include the emissions required to produce the feed — most corn produced in the U.S. is drenched in petroleum, whereas grass can have a negative carbon impact by storing carbon in its roots. Having a carbon policy that considers the entire supply chain would therefore impose a higher cost on industrial corn than grass, potentially shifting feeding strategies.
A promising technology for reducing manure emissions involves decomposing the manure in an enclosed chamber, capturing the emitted methane, and then burning it to produce electricity or heat for the farmer (or selling it back to the utilities). A dairy with a methane capture system, for example, could receive a tax credit (or something similar) that would offset part of the cow tax and allow lower prices or higher profit. Or it is possible that pasture management strategies or conversion of cropland to forest could sequester significant amounts of carbon, thus canceling out some of the emissions from the cows.
Costs and signals
The newspaper articles I linked to above provide estimates of an annual levy of $175 per dairy cow. Although discussions of dairy costs and prices are made difficult by many layers of government policy (price supports, quotas, and so on) and complex distribution systems, we can look at some numbers to provide a frame of reference. The December 2008 Livestock, Dairy, and Poultry Outlook from the USDA (PDF) estimates that the average dairy cow provided 2,380 gallons of milk (20,467 pounds) in 2008, meaning that a $175 annual tax would amount to about 7 cents per gallon. The USDA has also provided data on operating costs for dairy farms (Report ERR-47) that indicates that a $175 per dairy cow tax would increase operating expenses by a few percent.
Although there are certainly farms and consumers who can't handle a few percentage points increase in expenses or prices, we're not looking at some kind of apocalyptic burden — like prices doubling — that will cause havoc across the entire milk market. Policymakers will need to consider ways to help smooth the transition to a lower greenhouse gas economy.
Finally, one of the frequent points in climate change discussions is that there are currently no penalties for emitting greenhouse gas, and so consumers don't receive direct signals about their emissions. Sure, there are books, reports, articles, and blogs that explain how beef differs from pork or peanut butter and jelly, but it takes extra effort to learn the differences. Having the costs of greenhouse-gas emissions built into the product will bring the difference to the forefront and let market forces work their magic on our product choices and the shape of the economy.
Policies that help our society make the transition to a low-carbon living might be painful to certain producers and eaters in the near term, but the consequences of doing nothing will likely be far worse. It would be helpful if, for a start, politicians learned about the issues instead of giving knee-jerk responses that put one constituency ahead of the what's best for the public.
Data sources: The greenhouse-gas emission factor for wild fish is from Ambio, volume 34 (2005) 635-638; the farmed salmon emission factor is from Aquaculture, 272 (2007) 399-416; emission factors for sheep, beef and pork are from a report prepared for the Belgian Federal Office for Scientific, Technical and Cultural Affairs.