Greenhouse gas emissions and irrigation water use in the production of pulse crops in the United States

Abstract

Supplying our world’s growing nutrition needs in more sustainable ways has become an urgent global imperative, given the constraints of finite resources and the challenges of accelerating climate change. Pulse crops, which are the dried seeds of legumes such as dry peas, chickpeas, beans, and lentils, play a key role in maintaining affordable, nutritious diets, as they provide high amounts of protein and fiber, and relatively low amounts of fat. As legumes, they are also advantageous from an environmental perspective, because they fix atmospheric nitrogen, thereby reducing the need for added fertilizers. Although some pulse crops are produced in areas that require irrigation, more than 80% of the pulse crop production area in the United States is exclusively rain-fed. In order to quantify eco-efficiency metrics associated with the production of pulse crops in the United States, life cycle assessment techniques were used to calculate “cradle to farm-gate” greenhouse gas emissions and irrigation water use, both on a per unit of production basis. The results demonstrate that pulse crops have low carbon and water footprints relative to most foods, with greenhouse gas emissions of 0.27 kg CO2e/kg and irrigation water use of 0.19 m3/kg, both as national averages across all 2.4 MMT (millions of metric tons) of pulse crops currently produced annually in the United States.

Keywords

• climate change
• food security
• nutrition security
• sustainable agriculture
• pulse crops