Annual greenhouse gas emissions from all U.S. vehicles could be absorbed by forests, wetlands and agricultural lands – erasing a fifth of all greenhouse gas pollution, according to new research exploring natural climate solutions for the United States.
Peter Woodbury ’87, M.S. ’90, Ph.D. ’02, senior research associate in the College of Agriculture and Life Sciences, is a co-author on research published Nov. 14 in Science Advances.
The researchers analyzed 21 natural ways to mitigate climate change. They found that adjusting those natural management practices to increase carbon storage and avoid greenhouse emissions could equal 21 percent of the nation’s current net annual emissions. Increased reforestation could be equivalent to eliminating the emissions of 66 million passenger cars, according to the findings.
Improved management of existing croplands has an important role to play, according to the researchers. Woodbury, who led the cropland nutrient management portion of the study, and his colleagues found that many agricultural practices can significantly reduce greenhouse gas emissions.
Widespread adoption of cover crops – plants grown on farm fields when they would normally be left bare – aids in carbon sequestration and improves soil health, crop yields and yield consistency. The researchers also pointed to improved nutrient management practices that apply fertilizer when and where the crop needs it, using precision agriculture techniques.
These improved practices could reduce nitrogen use 22 percent, leading to a 33 percent reduction in field emissions and 29 percent reduction in upstream emissions with additional benefits for soil, air and water quality. In many cases, these practices also improve profitability for farmers.
“We have demonstrated that agriculture and forestry have real potential to both avoid greenhouse gas emissions and also remove carbon dioxide from the atmosphere and store it in plants and soil. At the same time, these practices have many other benefits such as improving soil health and water quality by reducing nutrient pollution of fresh water and the coastal zone,” said Woodbury, who develops models to quantify the sustainability of agricultural and forest ecosystems. Woodbury is a fellow at the Atkinson Center for a Sustainable Future.
The researchers pointed to biochar as one method with high potential, although further research is needed to overcome cultural, technological and cost barriers. In May, Cornell opened the largest pyrolysis kiln of its kind at a U.S. university to study the uses of biochar, a solid, charcoal-like material formed by heating biomass in the absence of oxygen. Biochar can help soil retain water and nutrients, as well as promote drainage when conditions are wet.
The researchers say that, along with reducing the impact of global warming, natural climate solutions have the potential to improve air and water quality, flood control, soil health and wildlife habitats.
Other solutions include: allowing longer periods between timber harvest to increase carbon storage; increasing controlled burns and strategic thinning in forests to reduce the risk of tree-killing fires; and reducing urban sprawl to preserve forests.
“These 21 natural climate solutions are really important because they can greatly reduce greenhouse gas emissions in the U.S. and the world while also providing other benefits including clean water, clean air and biodiversity,” said Woodbury.
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