Perennial Staple Crops
Reduced / Sequestered
(To Implement Solution)
The dominant agricultural crops are annual—planted, harvested, and replanted every year. Perennials come back year after year, with similar yield and higher rates of carbon sequestration. Many have been cultivated and harvested for millennia, and some are critical to the world’s food supply today, particularly in the tropics.
Staple foods from trees include starchy fruits such as bananas and breadfruit, oil-rich fruits such as avocado, and nuts such as coconut and Brazil. Many legumes are perennial, including pigeon peas, mesquite, and carob. Africa abounds with staple tree crops: baobab, mafura, argan, and more. These trees can take root in forest-farms, multistrata agroforestry, or intercropping systems.
Tropical staple tree crops can reverse erosion and runoff and create higher infiltration rates for rainwater. They can be grown on steep slopes and in a wide range of soils. They require lower inputs of fuel, fertilizer, and pesticides, if any at all.
Today, 89 percent of cultivated land, about 3 billion acres, is devoted to annuals. Lands converted from annuals to perennial staples sequester, on average, 1.9 tons of carbon per acre every year for decades. What’s more, perennial staple tree crops can weather and thrive under conditions that annuals cannot—vital in a warming world.
Perennial staple crops currently grow on approximately 50 million hectares, mostly in the tropics. Their rate of sequestration is high at 3.34 tons per hectare per year. Expand this area by another 61–141million hectares by 2050 and they can sequester 15.4–31.3 gigatons of additional carbon dioxide. Our analysis assumes that expansion only occurs on existing grassland, with no forest clearing. Because their yield is 2.4 times higher than annual staples—at 60 percent of the cost—savings are significant, ranging from US$1.4 to US$3.3 trillion, with an establishment cost of US$83–190 billion and lifetime operational cost of US$848–1922 billion.
Note: August 2021 corrections appear in boldface.