Projections of Future Cropland Abandonment: Impacts to Biodiversity and Carbon Sequestration
Abstract
Cropland abandonment occurs when ecological and economic shifts force farmers to retire lands formerly used to grow food. Without proper management, cropland abandonment can lead to soil erosion, inhibit nutrient cycling, increase wildfire risk, and threaten food security. However, if managed strategically, restoration of these abandoned lands can safely store climate-warming greenhouse gasses and enhance biodiversity. While historical cropland abandonment is well documented, patterns of future abandonment are not well-understood. The first stage of our project examines where croplands are projected to be abandoned globally under several future climate change scenarios, and where abandonment overlaps with important areas for biodiversity and climate change mitigation. We find that cropland abandonment will be widespread in 2050, but the amount and location of abandoned croplands vary by climate scenario. Projected abandoned croplands consistently overlap with areas important to biodiversity and carbon sequestration, highlighting valuable conservation opportunities.
The next stage of our analysis focuses on Brazil, an essential region for global climate change mitigation and biodiversity preservation. Given a conservation budget, our analysis identified regions of Brazil where projected abandoned lands can be managed to maximize benefits for biodiversity and carbon sequestration. Our findings indicate that while patterns of cropland abandonment vary by region, conservation goals can be met by leveraging abandoned lands with existing policy mechanisms. Through our research and analysis, we hope to inform effective policies and management strategies that balance the need for agricultural production with climate and biodiversity goals.
Rasters of abandoned cropland (globally and in Brazil) were generated by processing raw LULC data from Chen et al., 2021 between the years 2015 and 2050. Abandoned cropland was defined as any area currently classified as cropland that has a different land use classification in future projections, with the exception of land that was urbanized. Urbanized cropland was excluded from the analysis as these areas could not support our project goal of evaluating potential areas for natural restoration. Areas of global cropland abandonment were found using a series of raster calculations between future (2050) and current (2015) LULC data. Within Brazil, any area of cropland projected to be abandoned between 2020-2050 (and not urbanized) served as the input to our spatial prioritization.
Code for running these analyses are publicly available on the linked GitHub repositories.