Question to the Department for Transport:

To ask His Majesty's Government what assessment they have made of whether the combustion of synthetic fuels or biofuels of similar chemical composition to fossil kerosene has the same net radiative forcing effect as burning fossil kerosene when used as aviation fuel.

Aviation has climate impacts from both CO2 emissions and other (non-CO2) emissions, that need to be addressed. The impact of CO2 emissions can be quantified, while scientific evidence suggests that non-CO2 impacts from aviation currently represent two thirds of the net effective radiative forcing (ERF). However, this is not a fixed number and is scenario dependent, and there are large uncertainties that exist over the magnitude of non-CO2 impacts on the climate.

Sustainable aviation fuels (SAF) can deliver significant greenhouse emission savings. Scientific evidence suggests that SAF could also have a positive impact in reducing non-CO2 emission impacts. Recent research indicates that SAF can produce 50-70% fewer soot particles, which could reduce the overall warming effect of contrails.

Through the Jet Zero Strategy, we aim to address non-CO2 emissions by better developing our understanding of their impacts and potential mitigations.