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Carbon neutral goal won’t neutralise aviation’s climate impact says new report


Latest research shows that the International Civil Aviation Organisation (ICAO) and industry goal of carbon neutral growth in 2020 will not, as the name might suggest, neutralise aviation’s climate impact.

ICAO is meeting this week in Montreal to attempt to conclude 16 years of negotiations on a set of measures to tackle climate-change emissions from international aviation. Even if ICAO and industry were to be successful in stabilising aviation’s CO2 emissions at 2020 levels, which is an established goal, it would not correspond to a stabilisation of aviation’s climate warming impact. The longevity of CO2 already emitted into the atmosphere means that the sector’s climate warming impact will continue to grow long beyond 2020 as CO2 emissions accumulate in the atmosphere faster than they can be removed.

Aviation Emissions against Climate Warming Effect

The report by climate researchers at the Manchester Metropolitan University (MMU) shows that even constant, or ‘neutral’, annual aviation CO2 emissions from 2020 still result in an aviation ‘radiative forcing’ (warming effect) increase by a factor of 1.6 in 2050 over 2020 levels, and by a factor of 2.5 in 2100.

Real and effective measures to achieve the carbon neutral growth at 2020 goal would, the study says, reduce aviation’s radiative forcing in 2050 by 21% over the business-as-usual scenario. Previous research by the MMU has shown that deploying the maximum feasible reductions from technical, operational and biofuels measures, favoured by ICAO and industry, would only reduce aviation’s climate warming impact in 2050 by 9%.

The report concludes that to mitigate aviation’s climate warming impact in 2050 through carbon neutral growth in 2020 will require a basket of measures, including market-based measures, to bridge the gap between what can be achieved by industry and ICAO’s proposed measures, and what is actually needed.

Bill Hemmings, sustainable aviation manager at Transport & Environment, said:

ICAO’s head-in-the-sand approach, focusing on technology, operations and biofuels, falls far short of what is needed for our climate. This robust analysis is compelling and the science is clear: ICAO needs to consider the climate impacts of its CO2 mitigation goals when determining policy in Montreal.”

Analysis has already shown that continuing with the EU Emissions Trading Scheme (ETS) will reduce the 2050 radiative forcing by 19.5%. Achieving a 21% result through carbon neutral growth in 2020 will require ICAO to agree to implement a market-based measure (MBM) which is as effective as the EU ETS in delivering real emissions reductions. Combined with other measures, a global MBM starting in 2012, coupled with technology and alternative fuels, could reduce radiative forcing by around 30% by 2050, but ultimately stabilising the climate impact will require a more ambitious goal. The report did not consider aviation’s non-CO2 effects which will also contribute to a significant increase in radiative forcing nor whether offsets would bring real emissions reductions.

Tim Johnson, Director at the Aviation Environment Federation, said:

Even the modest goal of carbon neutral growth by 2020 will be impossible to achieve without a market-based measure as effective as the EU ETS, which Europe has been pressured to weaken. The international aviation community says it is serious about combatting the harm its industry does to the climate – now it must act to show these words are more than just hot air.”


The name of the report:  MMU: Climate impacts from aviation 2020 Carbon Neutral Goal: stabilized emissions but increasing radiative forcing and temperatures