The Global Potential of Bioenergy on Abandoned Agriculture Lands

TLDR

Converting forest or food‑agriculture lands to bioenergy threatens climate and food security, while abandoned agricultural lands cover 385–472 million ha—larger than previously reported—offering a potentially less harmful alternative. The study investigates whether using abandoned agricultural lands for bioenergy can avoid the climate and food‑security risks of converting other lands. We estimate the global bioenergy potential of abandoned lands by combining historical land‑use records, satellite‑derived land‑cover maps, and global ecosystem models, finding it to be less than 8 % of current primary energy demand. The mean above‑ground biomass yield is 4.3 t ha⁻¹ yr⁻¹, lower than earlier estimates, and the resulting energy supply would be under 10 % of primary demand in most developed regions but could exceed demand in several African countries with productive grasslands.

Abstract

Converting forest lands into bioenergy agriculture could accelerate climate change by emitting carbon stored in forests, while converting food agriculture lands into bioenergy agriculture could threaten food security. Both problems are potentially avoided by using abandoned agriculture lands for bioenergy agriculture. Here we show the global potential for bioenergy on abandoned agriculture lands to be less than 8% of current primary energy demand, based on historical land use data, satellite-derived land cover data, and global ecosystem modeling. The estimated global area of abandoned agriculture is 385−472 million hectares, or 66−110% of the areas reported in previous preliminary assessments. The area-weighted mean production of above-ground biomass is 4.3 tons ha−1 y−1, in contrast to estimates of up to 10 tons ha−1 y−1 in previous assessments. The energy content of potential biomass grown on 100% of abandoned agriculture lands is less than 10% of primary energy demand for most nations in North America, Europe, and Asia, but it represents many times the energy demand in some African nations where grasslands are relatively productive and current energy demand is low.