The U.S. Department of Agriculture (USDA) recently announced a set of voluntary and incentive-based initiatives aimed at reducing greenhouse gas (GHG) emissions in the agricultural sector. The Building Blocks for Climate Smart Agriculture & Forestry initiative expects to reduce U.S. emissions by 120 million metric tons of carbon dioxide equivalent, similar to taking 25 million cars off the road. This effort, made possible through existing authority underneath the Farm Bill, is good news as the agricultural sector accounts for 9% of total U.S. emissions and 13% of global emissions. Most emissions-related datasets do not count emissions from the conversion of forests to agricultural land or energy use as part of the sector’s contribution. These processes are huge contributors of carbon dioxide (CO2), but are accounted for in other categories.
Emissions directly associated with the agricultural sector are mainly methane (CH4) and nitrous oxide (N2O) due to livestock (the natural digestive process of enteric fermentation and manure management) as well as rice cultivation, the management of agricultural soils, and other sources.
Plants and animals sound simple enough to address, right? Not quite; food systems are complex with political, economic, and social interdependencies at their core. A comprehensive approach to reducing emissions while addressing these interdependencies has emerged and it’s called Climate Smart Agriculture (CSA). CSA is being used around the world and resources are now available to help others take this approach. How do the new USDA initiatives incorporate CSA? What makes CSA so smart? Let’s take a look:
Climate Smart Agriculture
CSA consists of three components: sustainably increasing agricultural productivity and incomes; adapting and building resilience to climate change; reducing and/or removing greenhouse gases emissions, where possible. CSA practices offer ways to transform agriculture and build resilience to climate change impacts, especially in smallholder farms and subsistence farming, while also allowing for less intensive techniques to be adopted.
Ok, that sounds great, but what are we really talking about here? Although different measures are often implemented in order to achieve CSA objectives depending on the context, some climate-smart agriculture techniques include:
- Decreased Use of Synthetic Fertilizers. Synthetic fertilizers are nitrogen-based in order to provide more nitrogen and other nutrients essential to increase crop yields, which unfortunately also means that they emit nitrous oxide (N2O). Yet other natural methods of obtaining these nutrients do exist; for example, composting manure and crop residues, “more precise matching of nutrients with plant needs, controlled release and deep placement technologies, or the use of legumes.” These methods allow for natural nitrogen fixation and reduces the need for synthetic fertilizers.
- No-Till. Tillage, often done with plows, is the overturning or loosening of soil to prepare it for seeds. The problem with tilling is that it is energy intensive, it reduces soil fertility and it also releases CO2 that was previously stored in the soil. Low or no-till farming saves energy and maintains soil health while sequestering carbon into the soil.
- Agroforestry. Agroforestry is a system in which trees and crops intentionally share the same piece of land. By integrating and blending forestry and farming together, the trees not only provide essential nutrients to the crops, but also act as a mitigation and adaptation measure by sequestering CO2 and defending against climate variability.
- Crop Rotations. By seasonally rotating the types of crops that are grown on the same piece of land, the use of nitrogen-based fertilizers can be reduced, thus reducing GHG emissions. Continually growing the same type of crop on a plot of land (Monocropping) depletes the soil of nutrients. When nitrogen-fixing bacteria, which is essential for crop yields, becomes depleted it is necessary to use more synthetic fertilizers to obtain this nitrogen.
- Anaerobic Digesters. Anaerobic digesters use agricultural and livestock waste to produce biogas that can be used for generating electricity. Through these digesters, methane from livestock manure is converted into biogas (which although emits CO2 is not as potent as emitting methane which has a global warming potential 25 times that of CO2).
- Soil cover keeping farm residues on top soil. No-till and agroforestry are ways to keep the crop residues on top of the soil. This acts as an adaptation measure as the protective soil cover shields the soil surface from extreme weather. Benefits include keeping the soil cooler and reducing moisture losses by evaporation in warmer conditions while “facilitating rain water infiltration, reducing soil erosion and the risk of downstream flooding” in extremely wet conditions.
Of course, CSA is not a one-size-fits-all approach, thus deployment in a large country in terms of land and economy will look different than smaller and/or developing countries. The U.S. also has long-standing agricultural subsidies in place and has a food system characterized by monoculture, synthetic fertilizers and pesticides, and large-scale cattle facilities, thus the challenges are significant.
CSA in the new USDA initiatives
The Building Blocks for Climate Smart Agriculture & Forestry program is intended to aid in achieving the Obama administration’s commitment to cutting the nation’s GHG emissions by 26-28% of 2005 levels by 2025 by targeting emissions in the agricultural sector. The initiative, which is voluntary and incentive-based, will be focused on the economic and environmental benefits of the CSA. It will also be focused on meeting the needs of producers, assessing progress and measuring success, and building partnerships. In regard to climate change mitigation and adaptation, the initiative uses various CSA techniques, including:
- Decreased Use of Synthetic Fertilizers. To reduce the use of synthetic fertilizers, the initiative emphasizes focusing on the right timing, type, placement and quantity of nutrients, thus not only reducing nitrous oxide emissions, but also providing cost savings through efficient application of fertilizers. The initiative will also promote compost application and the management of organic inputs in order to reduce fertilizer-related nitrous oxide emissions by 10% between 2010 and 2025.
- N0-Till. The initiative plans to add over 40 million acres of no-till farmland, in order to achieve 100 million acres of no-till farmland by 2025.
- Anaerobic Digesters. In order to address the issue of enteric fermentation, the initiative calls for the installation of 500 biogas digester plants over the next ten years.
- Soil cover keeping farm residues on top soil & avoid soil carbon loss. By adding 4 million more acres of rotational grazing by 2025 and supporting improved forage, soils management, the USDA’s Building Blocks for Climate Smart Agriculture & Forestry program will aim to reduce the loss of soil carbon.
The USDA program also emphasizes the importance of reporting emissions-related data. This is key considering 75% of agricultural producers targeted by the Carbon Disclosure Project (CDP) do not currently report their emissions.
Other aspects of the USDA’s new strategy on agriculture include encouraging urban forests, reforest federal areas disturbed by wildfire, insects, or disease, and improve farm energy efficiency. If all of the department’s 10 initiatives are implemented, it will mean a 120 million metric ton reduction in greenhouse gas emissions by 2025, enough to offset the emissions created by powering 11 million homes in 2014.
This initiative is just one step the U.S. can take in addressing greenhouse gas emissions from the agricultural and food sector. Although we welcome the voluntary-based measures, the United States should implement mandatory regulations that address both food production and consumption. With up to 40% of the food supply in the U.S. ending up in the landfill, and organic waste making up the second highest component of landfills (thus resulting in the largest source of methane emissions), simply addressing the supply side of the issue will only get us so far: food wasted also means wasted GHG emissions.