Agriculture’s Contribution to Climate Change

Agriculture’s most damning contribution to climate change is the release of carbon held in the soil, primarily from deforestation and land clearing. This is euphemistically referred to as “changes in land use” and exposes soil organic carbon to oxygen in the air, converting it to carbon dioxide. Since the dawn of agriculture 10,000 years ago or more, land clearing and degradation have resulted in 320 billion tons of emissions, 155 billion tons of which were released between 1850 and 2010. Two and a half trillion tons of carbon are currently held in the top meter of soils around the world, with an additional 560 billion in living aboveground biomass and detritus. Together these amount to six times the amount of carbon currently in the atmosphere. As of 2012, the rate of emissions from land clearing was 0.9 to 1.7 billion tons per year.

At present, most climate change impacts on agriculture are undesirable, except in some high-latitude regions. Food prices are projected to rise by as much as 84 percent this century. Declines of agricultural productivity of 15 to 30 percent are projected by 2080 in Africa, South Asia, and Central America. Chinese staple crop production suffers at 40 percent loss at 4 ° C. In some countries this could reach 50 percent loss of agricultural productivity, and in some regions agriculture will likely become impossible.

Further Learning: Reducing Agricultural Emissions

We can reduce carbon emissions from soil by slowing or ending land clearing and wetland drainage for agriculture, preventing erosion and reversing the degradation of agricultural soils, and reducing tillage. We can reduce fossil fuel emissions by reducing the use of mechanized equipment and cutting back on chemical nitrogen fertilizers, which are energy-intensive to manufacture. Likewise, we can reduce methane emissions by changing the way we farm.

Further Learning: Agroecological Intensification vs Industrial Food System

Clearing land for agriculture is responsible for 15 to 18 percent of human emissions today. Yet scientists and policy makers are concerned that we will need to increase food production substantially to feed a population of nine billion by 2050. In order to meet our needs without sacrificing more carbon-storing natural ecosystems, we’ll have to improve our yields on the farmland we already have— a challenge called agricultural intensification.

Sadly, industrial agriculture’s gains in yield have come at a huge social and ecological cost. This includes climate costs such as emissions from the manufacture and use of synthetic nitrogen fertilizers. For decades farmers, activists, and researchers have advocated for alternative agroecological production systems that can maintain these impressive yields without sacrificing people or ecosystems. Their arguments are being taken more and more seriously. In its 2013 report, Wake Up Before It Is Too Late: Make Agriculture Truly Sustainable Now for Food Security in a Changing Climate, the United Nations Conference on Trade and Development came out strongly in favor of agroecological intensification and strongly opposed to the industrial food system.

Source:

• Toensmeier, Eric (2016-02-22). The Carbon Farming Solution: A Global Toolkit of Perennial Crops and Regenerative Agriculture Practices for Climate Change Mitigation and Food Security. Chelsea Green Publishing. Kindle Edition.