Biofuels may not cut aviation contrail GHG emissions, says MIT study

The use of biofuels in jet fuel might not necessarily reduce global warming from contrails emitted by aircraft, according to a new academic study from the Massachusetts Institute of Technology.

The report comes as the UN’s aviation agency ICAO readies final criteria for its CORSIA offset scheme, through which various biofuels will be calculated on the basis of reducing greenhouse gas emissions.

Researchers ran a model based on three different scenarios that impacted the type of contrails generated by different types of fuels.

Last year, NASA said biofuels could reduce the global warming effect of contrails, a cloud-like vapour that magnifies the aviation sector’s contribution to climate change.

However, the MIT said the findings on the impact of biofuels were inconclusive.

“We find that even 67% to 75% reductions in aircraft soot emissions are insufficient to substantially reduce warming from contrails, and that the use of biofuels may either increase or decrease contrail warming—contrary to previous expectations of a significant decrease in warming,” the researchers found.

A baseline scenario based its assumption that the entire US aviation fleet used conventional jet fuel.

In the second scenario the study modelled that the entire aviation fleet operated on paraffinic biofuels which are the types of biofuel currently in production.

The final alternative calculated the carbon footprint based on fleets that use conventional jet fuel but at the same time use cleaner burning engines.