Global cooling induced by biophysical effects of bioenergy crop cultivation

Jingmeng Wang,Daniel Goll,Philippe Ciais,Laurent Z X Li,Jinfeng Chang,Thomas Gasser,Xiaomeng Huang,Wei Li,Olivier Boucher,Narayanappa Devaraju

doi:10.1038/s41467-021-27520-0

Abstract

Bioenergy crop with carbon capture and storage (BECCS) is a key negative emission technology to meet carbon neutrality. However, the biophysical effects of widespread bioenergy crop cultivation on temperature remain unclear. Here, using a coupled atmosphere-land model with an explicit representation of lignocellulosic bioenergy crops, we find that after 50 years of large-scale bioenergy crop cultivation following plausible scenarios, global air temperature decreases by 0.03~0.08 °C, with strong regional contrasts and interannual variability. Over the cultivated regions, woody crops induce stronger cooling effects than herbaceous crops due to larger evapotranspiration rates and smaller aerodynamic resistance. At the continental scale, air temperature changes are not linearly proportional to the cultivation area. Sensitivity tests show that the temperature change is robust for eucalypt but more uncertain for switchgrass among different cultivation maps. Our study calls for new metrics to take the biophysical effects into account when assessing the climate mitigation capacity of BECCS.

Highlights

Bioenergy crop with carbon capture and storage (BECCS) is a key negative emission technology to meet carbon neutrality
Based on the composite map, we performed five 50-year simulations with the IPSL-CM model to simulate the biophysical effects of different bioenergy crop cultivation scenarios: a reference scenario (Sref) where grid cells in the BECCS regions are fully occupied by food crops, and four idealized bioenergy crop scenarios (i.e., scenarios with cultivation of different bioenergy crops (Seuc), Sp&w, Smis, and Sswi) where all BECCS grid cells are assumed to be fully covered by a single type of the four bioenergy crops, with the remaining land cover being the same as in Sref
Even though the cultivation area occupies 3.8% ± 0.5% of the global total land area, bioenergy crops exert strong regional biophysical effects, leading to a global net change in air temperature of −0.08 ~ +0.05 °C

Summary

Introduction

Bioenergy crop with carbon capture and storage (BECCS) is a key negative emission technology to meet carbon neutrality. Using a coupled atmosphere-land model with an explicit representation of lignocellulosic bioenergy crops, we find that after 50 years of large-scale bioenergy crop cultivation following plausible scenarios, global air temperature decreases by 0.03~0.08 °C, with strong regional contrasts and interannual variability. Large-scale bioenergy crop cultivation with carbon capture and storage (BECCS) has been identified by integrated assessment models (IAMs) as a major negative emission technology (NET) for removing CO2 from the atmosphere[1,2,3]. We find that large-scale bioenergy crop cultivation induces a biophysical cooling effect at the global scale, but the air temperature change (ΔTa) has strong spatial variations and interannual variability. Compared to the herbaceous crops, changes in the energy fluxes induced by woody crops in the cultivation regions are larger, and the cooling effect is more robust across different cultivation maps

Methods

Results

Conclusion