An in-depth global examination of the links between climate and agriculture reveals the likelihood of an emerging feedback loop whereby, as climate change places more pressure on global food supplies, agriculture will necessarily adopt practices that could increase environmental impacts. This research, published in Scienceincludes extensive expert review, including from the Columbia University Mailman School of Public Health. The article also identifies new agricultural practices that have the potential to increase efficiency and stabilize our food supply in the coming decades.
The authors point out that greenhouse gas emissions from agriculture are now 18 times higher than in the 1960s, and are responsible for about 30% of global warming. Excess fertilizer left on agricultural land is broken down by bacteria into nitrous oxide, a greenhouse gas 300 times more powerful than carbon dioxide. Strategic efforts to reduce the warming effects of agriculture while maintaining high yields are essential for both mitigating climate change and protecting our food supply from its impacts.
“It is important to recognize that agriculture’s impact on human health, from pesticide use to water quality, will almost certainly be exacerbated by climate change,” said Lewis Ziska, PhD, associate professor of Environmental Health Sciences at Columbia Mailman. School of Public Health and co-author.
The research showed:
- Climate change has far-reaching consequences for agricultural practices: increasing water use and scarcity, nitrogen oxide and methane emissions, soil degradation, nitrogen and phosphorus pollution, pest pressure, pesticide pollution and loss of biodiversity.
- Climate and agriculture feedback pathways can dramatically increase agricultural greenhouse gas emissions. Without changes in agriculture, this feedback loop could make it impossible to achieve the Paris Agreement’s goal of limiting global warming to 1.5 to 2 degrees Celsius.
- Existing sustainable agricultural practices and technologies, if implemented at scale, can significantly reduce agricultural emissions and prevent a feedback loop from developing. To achieve this, governments must work to remove socio-economic barriers and make climate-resilient solutions accessible to farmers and food producers.
“We need agriculture, but the future of humanity also requires that we reduce the environmental damage of agriculture,” said co-author David Tilman, a professor at the University of Minnesota College of Biological Sciences. “By evaluating new practices being tried around the world, we have identified practices that appear to increase harvests while reducing damage to the environment. Once these new practices are tested and verified, we need an agricultural bill that pays farmers for both producing food and improving the environment. Enabling better stewardship has enormous benefits for all of us.”
The researchers looked at all aspects of the relationship between agriculture and climate to determine where new practices are most effective. While carbon sequestration is currently a priority, an integrated approach that takes into account agricultural efficiency and pollutants such as nitrous oxide could deliver much greater climate benefits and a more stable future for agriculture. Practices such as the use of precision fertilizers and crop rotation can prevent a feedback loop from developing.”
The team has identified a number of next steps. First and foremost, stakeholders must accelerate the adaptation and cost reduction of efficient and climate-friendly agriculture. Precision agriculture, perennial crop integration, agricultural voltaics, nitrogen fixation and novel genome editing are among emerging technologies that can increase agricultural production and efficiency while reducing the impacts of climate change. They recommend further research into feedback pathways for climate and agriculture and new technologies such as robots on farms.
