By Rosaly Byrd.
When it comes to the environmental impact of agriculture, many scientists, academics, and agriculturalists have different opinions on what is the “greenest” way to produce our food. Because modern agriculture is a complex system with various inputs and outputs depending on what is being produced, environmental impacts are difficult to measure and compare.
Let’s start with agriculture: organic vs. conventional agriculture. What are the environmental impacts of each? Many of you are probably thinking “what, I don’t get it? I thought one of the main reasons for organic farming is to reduce the ecological consequences that are associated with conventional farming”, and yes that is exactly true. We know that organic crops are grown without any chemicals or nitrogen-based fertilizers, therefore preventing chemical runoff into water systems, and also improving soil health. But what about other environmental impacts, specifically greenhouse gas emissions?
- Organic agriculture often uses crop rotation and no-till practices, which are both soil management techniques associated with carbon storage. Monoculture and tillage, techniques that are usually used in conventional agriculture, allow for carbon that was stored in the soil to be released back into the atmosphere, i.e. more CO2 emissions.
- Organic farming tends to use less energy since it doesn’t use nitrogen-based fertilizers that require lots of energy. Nitrogen-based fertilizers are also known for polluting water systems and creating dead-zones in oceans due to run-off.
- Yet the contradictions take root in this: Conventional agriculture results in high yields, which also often means less land and water needed to produce the same amount of a crop that was produced organically. Because of this, many are skeptical about the overall net environmental benefits/impacts of conventional vs. organic farming. Ideally, conventional farming could use more practices associated with organic farming, such as natural fertilizer and conservation tillage, in order to avoid using chemical products but at the same time ensure efficiency.
- The one environmental impact that scientists and academics are in accord is transportation. Greenhouse gas emissions from the transportation of both organic and conventional agriculture make up a large share of crops’ life cycle emissions. Eating local and seasonal vegetables is a wayto reduce the GHG footprint of your diet. Eating fruits and veggies that aren’t in season means they are usually coming from afar– think transportation emissions! Go to your nearby farmers’ market or get involved in a Community Supported Agriculture (CSA) program to make sure you are eliminating unnecessary GHG emissions that come from transporting fruits and vegetables. (Also, remember we are specifically talking here in this post about the environmental impact of these different types of farming, not health impacts!)
Now for you beef-eaters: grain-fed vs. grass-fed cattle. Which way of raising cattle is more harmful to the environment?
- Grass-fed cattle’s grazing helps keep carbon dioxide in the ground. Also, all the environmental impacts of agriculture mentioned above are involved in producing the grain to feed grain-fed cattle. This is almost completely eliminated with grass-fed cattle.
- Grain-fed cattle produce a third less methane than grass-fed due to the way the food is digested
- YET (again there is something else to take into consideration), grass-fed cattle take an extra eight months to grow compared to grain-fed cattle. That means extra water, land use, and waste. According to the Examiner, this is like adding almost one car to the road for every single animal, in terms of GHG. Also, what’s needed to feed grass-fed cattle? GRASS! This means that land converted for grazing, as is happening in the Brazilian Amazon in order to raise cattle. 75% of deforestation is actually a result of agriculture, in particular converting land to for cattle ranching (as well as soy).
- Lastly, methane, a GHG more potent than CO2, is released from enteric fermentation (digestion) from both grass-fed and grain-fed cattle (and actually slightly more so from grass-fed cattle because of the way cattle digest the grass). Enteric fermentation makes up 31% of direct agricultural emissions in the food system.
So what does it all mean? Is it better to eat grass or grain-fed cattle? This is a catch-22. Although grass-fed meat tends to be more efficient in terms of land-use (when forest land isn’t converted to grazing land), in reality, if we really want to reduce total GHG emissions, individuals should reduce the amount of meat they consume per week. The production of 1kg of beef protein requires about 16 times more land than the production of 1kg of soy protein. The NRDC also estimates that if all Americans “eliminated just one quarter-pound serving of beef per week, the reduction in GHG emissions would be equivalent to taking four to six million cars off the road.” In our other articles, “10 Tips for Reducing Your Holiday Environmental Footprint” and “15 Ways to be More Sustainable“, we mention reducing your meat consumption as ways to reduce your environmental impact, and this is the reason why.
For more information on meat, agriculture and the environmental implications, check out the Environmental Working Group (EWG)’s interactive Meat Life-Cycle guide or NRDC’s Eat Green Food Facts, both great tools to learn more about your diet.