Context:
Converting annual crops to perennial bioenergy crops can induce a cooling effect on the areas where they are cultivated, according to a new study.
Relevance:
GS-III: Environment and Ecology, GS-III: Agriculture
Dimensions of the Article:
- Energy crops
- Bioenergy crops and cooling effect
Energy crops
- Energy crops are low-cost and low-maintenance crops grown solely for energy production by combustion (not for food).
- The crops are processed into solid, liquid or gaseous fuels, such as pellets, bioethanol or biogas. The fuels are burned to generate electrical power or heat.
- The plants are generally categorized as woody or herbaceous.
Bioenergy crops and cooling effect
- Researchers found that global air temperature decreases by 0.03~0.08 °C, with strong regional contrasts and inter-annual variability, after 50 years of large-scale bioenergy crop cultivation.
- Cultivation area under bioenergy crops occupies 3.8 per cent ± 0.5 per cent of the global total land area, but they exert strong regional biophysical effects, leading to a global net change in air temperature of −0.08 ~ +0.05 degrees Celsius.
- The biophysical cooling or warming effects of bioenergy crop cultivation can significantly strengthen or weaken the effectiveness of bioenergy crop cultivation with carbon capture and storage (BECCS) in limiting the temperature increments, depending on the cultivation map and the bioenergy crop type.
Impact of this effect
- Large-scale bioenergy crop cultivation induces a biophysical cooling effect at the global scale, but the air temperature change has strong spatial variations and inter-annual 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 stronger and healthier across different cultivation maps.
- Cultivating eucalypt shows generally cooling effects that are more robust than if switchgrass is used as the main bioenergy crop, implying that eucalypt is superior to switchgrass in cooling the lands biophysically.
- Warming effects in Alaska and northwestern Canada may cause greenhouse gas release from thawing permafrost, from the four idealised bioenergy crop scenarios based on the composited cultivation map.
- Strong cooling effects in Eurasia, between 60°N and 80°N, may protect permafrost from thawing or reduce methane emissions from wetlands.
-Source: Down to Earth Magazine
