Relocating croplands could drastically reduce the environmental impacts of global food production

Robert M Beyer,Philip A Martin,Fangyuan Hua,Tim Rademacher,Andrea Manica

doi:10.1038/s43247-022-00360-6

Abstract

Agricultural production has replaced natural ecosystems across the planet, becoming a major driver of carbon emissions, biodiversity loss, and freshwater consumption. Here we combined global crop yield and environmental data in a ~1-million-dimensional mathematical optimisation framework to determine how optimising the spatial distribution of global croplands could reduce environmental impacts whilst maintaining current crop production levels. We estimate that relocating current croplands to optimal locations, whilst allowing ecosystems in then-abandoned areas to regenerate, could simultaneously decrease the current carbon, biodiversity, and irrigation water footprint of global crop production by 71%, 87%, and 100%, respectively, assuming high-input farming on newly established sites. The optimal global distribution of crops is largely similar for current and end-of-century climatic conditions across emission scenarios. Substantial impact reductions could already be achieved by relocating only a small proportion of worldwide crop production, relocating croplands only within national borders, and assuming less intensive farming systems.

Highlights

Agricultural production has replaced natural ecosystems across the planet, becoming a major driver of carbon emissions, biodiversity loss, and freshwater consumption
The conversion of nearly half of the world’s ice-free land area to agricultural areas[1] has contributed to three of humanity’s most pressing environmental challenges[2,3]: (i) agriculture is a major source of anthropogenic greenhouse gas emissions[4–6], largely from the release of carbon stored in natural vegetation and soils[7,8]; (ii) agriculture is the main driver of habitat loss, the greatest threat to terrestrial biodiversity[9–12]; and (iii) agriculture is responsible for about 70% of global freshwater consumption[13,14], leading to shortages of potable water in many arid parts of the world[15,16]
We estimate that a complete optimisation of the spatial distribution of croplands would simultaneously reduce the current carbon and biodiversity impacts of global crop production by 71% and 87%, respectively, whilst eliminating the need for irrigation altogether (Fig. 1)

Summary

Introduction

Agricultural production has replaced natural ecosystems across the planet, becoming a major driver of carbon emissions, biodiversity loss, and freshwater consumption. All estimates were derived assuming only rainfed water supply[42]; any configuration of croplands based on them represents a scenario in which no systematic irrigation is required Using these potential yields, we considered all possible spatial distributions of rainfed croplands for which the total global production of each individual crop was the same as at present (see the “Methods” section). The area assumed to be potentially available for agriculture in a grid cell was defined as the area not currently covered by water bodies, land unsuitable due to soil and terrain constraints, urban areas and infrastructure, crops not included in our analysis, pasture lands, and protected areas (see the “Methods” section) Among all such distributions of croplands, we identified those for which global carbon and biodiversity impacts were minimal. On the 20 arc-minute (0.33°) grid used here, this required solving a ~1-million-dimensional linear optimisation problem (see the “Methods” section)

Methods

Results

Conclusion