• A POSTnote on climate change and aviation will look at the carbon footprint of commercial flights.
  • It will review potential technical solutions and other policy options including carbon offsetting and ways to reduce flight demand.
  • Work on this POSTnote has been completed. You can read Climate change and aviation and Low-carbon aviation fuels online. Updated 24 February 2020.

There is long-standing and often controversial debate around the commercial aviation sector’s response to climate change. Aviation has expanded substantially since the 1990s and is set to double by the mid-2030s. Despite accounting for just 2% of direct global greenhouse gas emissions, it has a disproportionate contribution to climate change, as non-CO2 greenhouse gases and condensation trails released or created at high altitude have a stronger greenhouse gas effect. Combined, these can almost double a flight’s greenhouse effect. Moreover, few ready technical solutions exist for reducing emissions from aviation in the short-term: potential approaches include new aircraft and engine designs, increased operational efficiency, new fuels and electric propulsion systems. Some of these can only provide incremental efficiency gains and have already been exploited, while others are at low levels of technological readiness. Fully-electric aircraft are not expected for long-haul flights for many decades because of the low energy density of batteries relative to jet fuel (making the large mass of batteries needed prohibitive). Hybrid aircraft (using a combination of electric and jet fuel propulsion) may be commercially available from the 2030s or 2040s. New propulsion systems may facilitate the introduction of ‘electric taxis’ (for intra-urban transport) or ‘blended wing’ commercial aircraft designs (whereby the wings and fuselage are integrated, precluding the need for a cigar-shaped cockpit), which are more aerodynamically efficient than conventional designs. 

However, controversy exists around the appropriate balance between reliance on technical solutions and pursuing demand reduction measures for commercial air travel. International approaches to mitigating aviation emissions centre on, often controversial, carbon offsetting schemes. This POSTnote would outline the current and future contribution of the commercial aviation sector to climate change, potential technical solutions to reducing emissions, and potential UK and international policy frameworks for reducing emissions, including through carbon offsetting and demand curtailment.