Climate Change and Agricultural Greenhouse Gas Emissions

Agricultural Emissions

Annual greenhouse gas emissions linked to human activity reached 49 million tons (49 gigatons) of carbon dioxide equivalents (GtCO2e) in 2010, the highest annual amount ever recorded and an increase of 10 GtCO2e (or about 25%) since 2000. The agriculture, forestry and land use sector was responsible for 24% of emissions in 2010 (11.8 GtCO2e); second only to the energy sector. 

In the agriculture sector, emissions from “crop and livestock production” exceeded emissions from “land use, land use change, and forestry, including deforestation.” The contribution of agriculture as a source of emissions varies widely by country due to the efficiency and type of agricultural system. For example, in 2010, emissions from agriculture accounted for 9% of greenhouse gas emissions in the United States; yet accounted for 29% of emissions in developing countries. 

Projected Agricultural Emissions Growth

Population growth and income-driven dietary shifts are projected to increase agricultural emissions by 80% by 2050.

Population Growth- Feeding 2.2 billion more people in 2050

The world population was 7.6 billion in 2017, an increase of one billion people over the last 12 years. Though fertility rates are declining, and are expected to continue declining, the global population is nonetheless expected to grow to 8.6 billion in 2030, 9.8 billion in 2050, and 11.2 billion in 2100. Most of the predicted population increase will be concentrated in Africa and Asia: by 2050, it is estimated that compared to 2017, there will be 1.3 billion more people living in Africa, 750 million more in Asia, and modest growth everywhere else but Europe, where population may decline slightly. To meet food demand, increases in agricultural production are expected to increase emissions from agriculture if production continues along the same emissions trajectory. 

Income-Driven Dietary Changes

Changes in diet will strongly affect future greenhouse gas emissions from food production. Globally, per capita food supply increased from 1961 to 2002; though food supply in developing countries increased by 31%, food supply in developing countries was still lower than in developed countries. Compared to average diet in 2009, the average diet in 2050 will have 15% more total calories, a shift predicated on global economic growth and associated increase in household income. Dietary shifts toward higher calorie consumption, particularly from meat, sugar and fat, would increase per capita greenhouse gas emissions by 32%. 

In developing countries, the rate of growth in consumption of calories from animal-based protein is projected to increase much more quickly than overall calorie consumption (123% compared to 31%). While livestock products provide protein and a wide range of essential micronutrients, production of animal products, especially ruminants, is more emission-intensive than other food sources. Livestock-related greenhouse gas emissions stem largely from enteric fermentation (digestion in ruminants) and manure (manure management on farms and manure left in pastures). Fertilizers and energy used for growing livestock feed also contribute to greenhouse gas emissions. Increased livestock production due to growing demand for meat also has been linked to the destruction of forests and grasslands.

Food Loss and Waste

Approximately 30–40% of all food produced is lost or wasted in the supply chain. In developing countries, most food is lost on farm or during distribution due to poor storage, transportation, and conservation. In developed countries, much more food is wasted in service sectors and at the consumer level.  Food losses occurring at agricultural production phases appear homogenous across regions, representing about one-third of each region’s total food loss and waste, but waste at the consumption end of the supply chain is much more variable; 31–39% of food is wasted in middle- and high-income regions and 4–16% of food is wasted in low-income regions.

Food wasted at the consumer level in industrialized countries (222 million tons) is almost as high as the total net food production in sub- Saharan Africa (230 million tons). The global economic, environmental, and social cost of food wastage is estimated at USD$2.6 trillion, which is nearly equal to the GDP of France. Food loss and waste represents lost income, generates unnecessary greenhouse gas emissions, and wastes both water and land, negatively impacting natural ecosystems. Food loss and waste accounted for about 4.4 GtCO2e/yr., or about 9% of all emissions, according to a 2013 study. This amount includes emissions from the agriculture sector, industry (production of fertilizer), transportation (moving food around), buildings (storage), and energy (refrigeration). 

Reducing food loss and waste can reduce GHG emissions by 0.6–6.0 GtCO2e/yr. A goal of reducing food waste along the food supply chain by about 50% is considered feasible. By comparing food availability and food requirements country by country, experts estimated that up to 14% of emissions from agriculture in 2050 could be avoided by managing food use and distribution better.

Company Investment in Agricultural GHG Mitigation

A trajectory with increasing agricultural emissions will not limit global warming to less than 2°C above pre-industrial levels. To limit global warming to less than 2°C, global greenhouse gas emissions will need to be 40% to 70% lower in 2050 than in 2010, combined with large increases in carbon sequestration. Delay in implementing mitigation efforts will substantially decrease policy and economic options and increase the difficulties of transitioning to a low-emission economy.

Major investments in systemic change to supply chains are necessary to achieve substantial reductions in emissions in agriculture. While public financing is often discussed as a solution in the international community, the private sector was responsible for two-thirds and three-fourths of all mitigation finance globally between 2010–2012. Most likely, both public and private financing will be necessary.

Until recently, many food companies focused on measuring and reducing emissions from operations, for example by reducing their electricity consumption or fuel emissions from transportation and distribution. However, for most food companies, the biggest source of greenhouse gas emissions occurs in the agricultural production portion of the supply chain. In order to meet our collective commitment to limiting warming to 2 degrees, food companies must widen their focus beyond direct operations to work with their suppliers to report and reduce greenhouse gas emissions across supply chains. Reducing emissions from agriculture is both necessary and achievable.