Thu 29 Jan 2015 – Whereas there is a portfolio of opportunities for decarbonisation in the short and medium term for shipping, this is not the case for aviation and so demand management will be required to address the sector’s rising emissions. These are the conclusions of a study published in the journal Climate Policy by Alice Bows-Larkin of the Tyndall Centre for Climate Change Research. The paper explores the similarities and differences between the shipping and aviation sectors in the context of avoiding a 2 degrees C temperature rise and finds that a reliance on global market-based measures to deliver the required CO2 cuts will likely leave both at odds with the overarching climate goal.
The paper presents analysis from the International Energy Agency that shows aviation and shipping CO2 grew by 78-83% between 1990 and 2010, a period when global CO2 growth from the aggregate of other sectors grew by closer to 40%. By 2010, it says, CO2 emissions from aviation and shipping were of a similar magnitude to those from the entire continents of either Africa or South America.
Referencing studies elsewhere, a range of scenarios for international aviation CO2 show rises up to 515% between 2000 and 2050, although more typical figures are around 220%. For any sector to do less than the average places considerable pressure on others to mitigate more in the effort to avoid 2⁰ C, says the paper.
The author challenges the view that measures such as emissions trading can deliver a satisfactory outcome for international aviation and shipping to play their fair part in delivering on 2⁰ C and that they allow the sectors to grow as much as demand for their services requires. Firstly, she says, if a strict global carbon cap was in place, the carbon prices necessary to achieve an urgent and rapid cut in CO2 would have to be substantially higher than those countenanced by policy makers. Secondly, waiting for a scheme to begin, with a probable phase-in period on top, would still mean a global growth in CO2 that would consume more than a fair proportion of the available carbon budget given emissions need to reach a peak, the author estimates, by 2020.
The industry’s target of a net CO2 cut of 50% by 2050 from 2005 falls substantially short of the 80% cut necessary to remain within a 2⁰ C budget, “even with trading functioning successfully,” argues Bows-Larkin.
“The rapidity with which the CO2 budget is being consumed requires immediate cuts in CO2 growth rates across all sectors. As long as aviation and shipping are outside of a global and strictly bound trading scheme, 2⁰ C implies CO2 growth rates need to be near zero by 2015 to 2020.”
Technology and operational change will not be sufficient to deliver such a shift in the aviation sector in the short term, although this could be the case for shipping, she says, where opportunities exist to use a range of potential alternative fuels and low-carbon technologies, as well as ‘slow-steaming’, in which slowing the speed of ships can deliver immediate cuts in CO2.
For aviation, this implies a need for demand-side intervention, at least in developed nations, she recommends. “Policies that could intervene include a moratorium on airport expansion, the implementation of an individual carbon quota scheme to include flights or, if considered feasible, additional price mechanisms to curb growth to the extent required to stay within the budget.”
Adds Bows-Larkin: “Technologies to cut CO2 in the required timeframe are few and far between. Nations where per capita flying as well as growth rates are high have no option but to consider constraining growth in the short term, until fuel efficiency improvements or the use of biofuel can more than offset the CO2 produced by a further rise in passenger-km.”
For aviation, pinning so much hope on emissions trading to meet the 2⁰ C challenge is misguided, she concludes.
‘All adrift: aviation, shipping, and climate change policy’ paper
Tyndall Centre for Climate Change Research
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