January 17, 2011:
The Surprising Connection Between Food and Climate Change
…We are not bystanders. Each of us is a player in one of the biggest stories ever. Global warming isn’t just happening on the grand scale—to icebergs somewhere out there or in deliberations in capitals of far-off cities. Global warming is happening to us, right here, right now, in very real ways every day. And we, in turn, can be a part of transforming the climate-change story from one of hopelessness to one of renewal, regeneration, and resilience. There are powerful ways to be part of this historic shift: among them, aligning ourselves with a sane food system in our own communities, supporting the work globally to shift toward food sustainability, and honoring those farmers who are—we now can see—among the planet’s real climate heroes.” –Anna Lappé, Diet for a Hot Planet
As many communities around the world are making preparations for the effect that climate change will have on their food security, it is a dangerous oversight to neglect the reverse effect: the impact that our global food system has on the climate.
Food production worldwide is one of the major emitters of greenhouse gases (GHGs) into our atmosphere, including carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). On average, estimates of the contribution of food production to global warming are in the range of 30% of the total anthropogenic (i.e., manmade) GHGs. Some estimates are as high as 50%[1]. This means that in terms of climate change what we eat is more important than what we drive, where we set our thermostat, or what kind of light bulbs we use.
When compared to a carbon dioxide molecule, methane has 72[2] times the warming potential as CO2, and nitrous oxide has 310[3] times the warming potential as CO2. Nitrous oxide is considered to be the most potent and important greenhouse gas of all. All three of these gases are released into the atmosphere from various types of food production and transportation methods, but the industrialized, meat-based food consumed in the west are the most egregious emitters of greenhouse gases.
Because GHGs have a global impact, it does not matter where they are released into the atmosphere. Therefore, it is important to introduce the concept of GHG responsibility instead of just local GHG emissions. Unfortunately, most protocols for assessing a community’s global warming footprint, including the one used by Boulder, do not take this approach. They only account for GHGs that are emitted locally[4]. What is lost is the impact that food choices and consumption have on our contribution to global warming. This is a dangerous oversight because the most cost-effective and fast-acting ways to reduce GHGs in the atmosphere involve food choices that we all make three times a day.
Armed with an understanding of how various foods contribute to global warming, every one of us can immediately, for zero net cost, make significant reductions in our personal responsibility for GHG emissions. As a community, investing in public outreach and education about the impact of food choices on global warming is a far more cost-effective way to reduce GHGs than installing solar panels, compact fluorescents, and insulation.
There are three things to consider when assessing the climate impact of foods: what the food is, how it is produced, and where it comes from. By far the most significant producers of GHGs are meat and dairy products. This is not only because livestock production is the single biggest source of anthropogenic methane, but also because the inefficiency of livestock production has a multiplying effect for carbon dioxide and nitrous oxide creation. The methane comes from two sources: enteric fermentation in the guts of cattle and released via belching, and from anaerobic manure lagoons. As stated earlier, methane has 72 times more global warming effect than carbon dioxide. Also, because methane only remains in the atmosphere for about eight years, as opposed to 100 years for carbon dioxide, reductions in methane made today will have a relatively fast impact on our climate.
Livestock production, particularly beef, is incredibly inefficient. It requires as much as 50[5] calories of input for every calorie of protein output. Therefore, meat production can require massive amounts of land to grow corn and soy to feed cattle. As meat consumption rises, forested areas are cleared for increased capacity. Clearing forests releases sequestered carbon, so the GHG impact is even more severe. Industrial scale corn and soy farms use huge amounts of fertilizer, which is the source of nitrous oxide as the ammonium-based fertilizes react in the soil.
By rethinking the way we approach meat and dairy products in our diet, we can each make a significant reduction in our individual responsibility for greenhouse gases. We can treat these foods as a side dish instead of the main course, and when we do eat them, choose grass-fed, organic and local.
The way food is produced, whether animal or vegetable, is the next consideration. Certainly, the easiest differentiator is the degree to which a food is processed and packaged. Fresh, unprocessed and minimally packaged foods require less energy to get them from the farm to our plates. But a vital consideration is also how the food was grown.
Organic farming methods use no fossil fuel based fertilizers and chemicals, and organic methods return carbon to the soil instead of releasing it into the atmosphere. Conventional farming methods, on the other hand, apply ammonium-based fertilizers which results in nitrous oxide formation—the most potent greenhouse gas. Where organic farming methods rely on a living soil for nutrients and sequesters large amounts of carbon per acre, conventional farming relies on chemicals and releases carbon.
Finally, the distance a food travels from farm to plate, or “food miles,” matters. In the worst case, perishable foods shipped around the world are the biggest offenders of food-mile carbon consumption, as they are most likely air shipped and refrigerated. In the best case, local, in-season produce purchased directly from a farmer has virtually no food-mile based carbon impact. Most likely, these farmers will also use organic methods.
So, a low meat and dairy diet, minimally packaged and processed, purchased from a local organic farmer, is the optimal way to reduce our impact on global warming. This is far easier and less expensive than installing solar panels or buying a hybrid car. And, as added benefits, this diet is also better for our health, better for local economies, better for our water quality, better for animals and biodiversity, and better for the billions of people around the world whose subsistence lifestyle is encroached upon by industrial agriculture.
It is commendable that Boulder County is working to reduce our collective wide greenhouse gas footprint. But we are currently ignoring the most economically viable and technically effective way to go about this. Solar panels and hybrids and home insulation are all good things, but with limited time and resources, we should approach food as the front line to combating climate change. A vital component to our Climate Smart programs should be a “Food Smart” program.
[1] “Livestock and Climate Change”, Robert Goodland and Jeff Anhang, World Watch, November/December 2009
[2] The global warming potential of methane is stated in two different ways relative to time duration. Because a molecule of carbon dioxide remains in the atmosphere for over 100 years, methane is often compared to CO2 over that same period with a warming potential of 25 times that of CO2. However, methane only really lasts 8 years in the atmosphere, so the more relevant time duration of 20 years results in a warming potential of 72 times CO2.
[3] “Production and Mitigation of Greenhouse Gases in Agriculture”, Jenifer Wightman, Cornell University
[4] “The Greenhouse Gas Protocol”, World Resources Institute
[5] “Livestock Production: Energy Inputs and the Environment”, David Pimentel, Cornell University
