Bio-Energy Crops Have a Cooling Effect on Cultivated Areas: Research

According to a new study, converting annual crops to permanent bio-energy crops can result in a cooling effect in the areas where they’re grown. Bio-energy crop cultivation covers just 3.8- 0.5 percent of the global total land area, but it has a significant regional biophysical impact, resulting in a global net change in air temperature of 0.08 to +0.05 degrees Celsius

Research Insights:

After 50 years of large-scale bio-energy crop production, researchers discovered that global air temperature drops by 0.030.08 °C, with considerable regional disparities and inter-annual variability.

Depending on the cultivation map and the bio-energy crop type, the biophysical cooling or warming impacts of bioenergy crop cultivation can greatly strengthen or reduce the effectiveness of Bio-energy Crop Cultivation with Carbon Capture and Storage (BECCS) in controlling temperature rises.

On the global scale, large-scale bio-energy crop cultivation has a biophysical cooling effect, but the air temperature change has considerable geographical and inter-annual variability.

Woody crops cause bigger changes in energy fluxes in the cultivated zones than herbaceous crops, and the cooling effect is stronger and healthier across different cultivation maps, according to a study published in Nature Communications.

The researchers looked at the biophysical climate consequences of large-scale bio-energy crops to thoroughly assess their contribution in climate mitigation, led by Jingmeng Wang of Tsinghua University's Institute for Global Change Studies in Beijing.

The researchers used a computer model to estimate the biophysical climate impact of various bio-energy crop development scenarios in the future. The bio-energy crops employed in the study were eucalyptus, poplar, willow, miscanthus, & switchgrass.

Temperature changes in bio-energy crop scenarios could have huge geographical variability and important climatic teleconnections to other parts of the world, according to the study.

Warming effects in Alaska and northern Canada could result in greenhouse gas emissions from thawing permafrost, as well as from the four idealized bio-energy crop scenarios based on the composited cropping map.

Strong cooling effects between 60°N and 80°N in Eurasia may preserve permafrost from thawing and limit methane emissions from wetlands.

The study also highlighted the significance of crop type selection, the original land-use type on which bio-energy crops were expanded, total cultivated area, and spatial dispersion patterns.

Eucalyptus- Higher Cooling Effects:

Growing eucalyptus has more robust cooling effects than growing switchgrass as the primary bioenergy crop, implying that eucalyptus is superior to switchgrass in terms of biophysical cooling.

Switchgrass replaces forests, which has biophysical warming effects as well as the potential to release more carbon through deforestation than converting other short vegetation to bio-energy crops.

As a result, deforestation should be avoided. The overall area under cultivation has an impact on the extent of changes in biophysical consequences.

Eucalyptus has higher cooling effects, while switchgrass has the most warming effects.

The study found that the biophysical consequences of bioenergy crop production not only affect global temperature directly but also have secondary effects on natural greenhouse gas fluxes, which should be considered when considering large-scale BECCS deployment.

(Source: Down to Earth)