Scientific community needs to bridge disciplines to find further solutions to the climate crisis, a new study says

 

POSTED ON Dec 08, 2022

 

Arizona State University (ASU) announced recently that a team of researchers has found that planting grass on poor soil will provide enough biomass feedstock to meet the liquid fuel demands of the U.S. aviation sector.

The researchers said that in finding further solutions to the Earth’s climate crisis it is important that the scientific community bridges disciplines to move past incremental reductions in emissions. ASU’s interdisciplinary team drew expertise from a spectrum of domains: ecosystems sciences, climate modeling, atmospheric sciences, and economics. The research was a culmination of eight years of modeling work and collaboration.

According to the research published in the journal Nature Sustainability, there is a pathway toward full decarbonization of U.S. aviation fuel use by substituting conventional jet fuel with sustainably produced biofuels.

The study found that planting the grass miscanthus on 23.2 million hectares of existing marginal agricultural lands – land that often lays fallow or is poor in soil quality – across the United States would provide enough biomass feedstock to meet the liquid fuel demands of the U.S. aviation sector fully from biofuels, an amount expected to reach 30 billion gallons/year by 2040.

In the study, the researchers used an integrated framework of land assessments, hydro-climate modeling, ecosystem modeling, and economic modeling to assess where and under what conditions across the United States, energy crops used for bio jet fuels could be grown sustainably using criteria that evaluate both environmental and economic performance. 

The team first identified and assessed where marginal agricultural lands already existed in the U.S. They then assessed whether or not one could grow the right energy crops on the land without using additional water. The team then analyzed whether growing energy crop feedstocks on these lands would have detrimental effects on the surrounding climate or soil moisture and predicted the potential productivity of yields of two different kinds of grass – miscanthus and switchgrass – as suitable biomass energy feedstocks.

Finally, the team quantified the amount and the cost of bio jet fuel that would be produced and distributed nationwide at scale. The scientists emphasized that this integrated systems perspective was critical to the study. In the past, research around the potential of biofuels has largely consisted of isolated assessments that have not been well-integrated, for example, overlooking key data on how the altering crop cover influences the surrounding climate.

“When you plant crops over strategically designed areas, the planting of these crops has an impact on the climate,” said Matei Georgescu, co-corresponding author of the study and associate professor in the School of Geographical Sciences and Urban Planning and director of the Urban Climate Research Center at ASU.

To account for land-atmosphere interactions, the research team took outputs from their hydroclimate model to inform their ecosystem model. The team then evaluated the economic feasibility for farmers to grow these grasses. The researchers in their analysis benchmarked the financial returns of the existing uses for the lands they identified – some already are used for growing corn, soy, or various other crops, and others are being used as pasture – against those from cultivating either miscanthus or switchgrass as biomass feedstock.

Growing miscanthus or switchgrass needed to be more profitable to replace the existing use of the land in each area.  In the end, researchers found miscanthus to be the more promising feedstock, and biojet fuels derived from miscanthus can meet the 30 billion gallons/year target at an average cost of $4.10/gallon.

While this is higher than the average price for conventional jet fuel the team concluded it is reasonable when considering biojet’s potential to cut emissions.