The IPCC have published the third and final section of their latest comprehensive review of climate science IPCC Working Group III report: Climate Change 2022: Mitigation of climate change. Drawing on the work of thousands of scientists, the report has taken about seven years to compile and as such potentially the last warning before the world is set irrevocably on a path to climate breakdown. You can read the report here >> https://www.ipcc.ch/report/ar6/wg3/



The IPCC report notes that transport emissions have continued to rise, consistently rising at an average of 2% per annum between 2010 and 2019. 


Whilst the report does not have clear policy recommendations for decarbonising aviation, it does note the importance of efficiency improvements, sustainable biofuels and alternative flight. Unlike the comments on land-based vehicles (in which it notes electrification has large potential to reduce emissions) it argues that electrification could only play a “niche role for aviation and shipping for short trips” and as such decarbonising aviation will be different when compared to other modes of transport. 


The report’s mitigation chapter also includes shifting transport , specifically noting that we should reduce air travel. 


Key findings in relation to aviation include:


  • CO2 emissions mitigation technologies for aviation will be required and these options require more R&D
  • Efficiency improvements (optimised aircraft and vessel designs, mass reduction and propulsion system improvements) can provide some mitigation potential, but technologies will be needed on top of this
  • Increased efficiency alone has been insufficient to limit emissions from aviation and natural gas-based fuels are expected to be inadequate to meet stringent decarbonisation goals
  • “High energy density, low carbon fuels are required but they have not yet been reached on a commercial scale”
  • Advanced biofuels could also provide low carbon jet fuel but need more R&D
  • “The production of synthetic fuels using low-carbon hydrogen with CO2 captured through DACCS/BECCS could provide jet and marine fuels but these options still require demonstration at scale”
  • Electrification has a role in reducing emissions from airport operations

Carbon removals 


Though the report found it was now “almost inevitable” that temperatures would rise above 1.5C – the level above which many of the effects of climate breakdown will become irreversible – the IPCC said it could be possible to bring them back down below the critical level by the end of this century. As expected, the report sets out a significant role for carbon dioxide removals over the next century, saying “the deployment of CDR to counterbalance hard-to-abate residual emissions is unavoidable if net zero CO2 or GHG emissions are to be achieved." Indeed the report features a cross-sector chapter on mitigation options that cut across sectors, including carbon dioxide removal techniques. 


Key findings in relation to carbon removals include:


·       Pathways that limit warming to 1.5C with minimal overshoot earmark up to 780 gigatonnes of BECCS and up to 310 gigatonnes of DACS between 2020-2100

·       CDR fulfils 3 roles: 1. Lowering net emissions in the near-term. 2. Counterbalancing 'hard to abate' residual emissions (E.g./aviation/shipping/industry). 3. Achieving net negative emissions in the long-term if deployed beyond the levels of annual residual emissions

·       The way to enable CDR is: 1. Accelerated research, development and demonstration. 2. Improved tools for risk assessment and management. 3. Targeted incentives and development of measurement methods. 4. Reporting and verification of carbon flows