Aviation undoubtedly poses a number of threats to our environment. These are, most notably, air pollution, noise pollution, and climate change. And yet the number of flights continues to increase along with passenger demand, as the government considers expanding further the UK’s aviation capacity.
Some of these problems can be mitigated through policy, and progress can be seen already. But others are harder to resolve. This blog will examine the environmental impacts of aviation, the effectiveness of government action so far, and options for further mitigation.
First, aviation produces harmful air pollution that damages public health, including nitrogen dioxide, nitrous oxide, and particulate matter. A 2015 study by the Massachusetts Institute of Technology (MIT) revealed that ozone and particulate matter from aircraft contributed to 16,000 premature deaths annually around the world, with an estimated cost of $21 billion a year. A 2012 paper, also from MIT, found that emissions from UK airports were responsible for 110 early deaths each year.
Second, aviation generates high levels of noise pollution. As well as impairing the quality of life of local residents, noise can also cause health impacts. In a 2015 report, researchers from Queen Mary University found aviation noise had a serious impact on cardiovascular health, psychological well-being, and children’s cognition and learning.
Finally, aviation is a major source of greenhouse gas emissions which contribute to climate change, making up 5.9% of the UK’s total emissions. The Committee on Climate Change (CCC) noted in their recent report that between 2009 and 2014 aviation emissions have been broadly flat. The International Civil Aviation Organisation (ICAO), a UN body, estimates that globally aviation accounts for around 2% of all greenhouse gas emissions, a small but significant portion.
Effectiveness of government action so far
The government’s air quality plan, published in December 2015, focuses mostly on reducing air pollution from road transportation. However, it notes that nitrogen dioxide emissions from aircraft will gradually decrease as the ICAO tightens the regulations that cap emissions during landing, taxi, and take-off. There is also huge potential for innovation in manufacturing to continue developing more efficient engines that emit fewer toxicants into the air.
Changes to the design of aircraft are also able to mitigate noise. From 2017, new ICAO-enforced regulations will require large civil aircraft engines to be at least seven decibels quieter than current designs, with similar regulations for smaller aircrafts to follow in 2020.
Carbon emissions from aviation have been reduced by greater engine efficiency. The ICAO state that engines have become 70% more efficient since the 1970s. Sustainable alternative fuels, such as biofuels (purpose-grown crops) or hydrogen, have also been developed, and have now powered 2,500 commercial flights, according to ICAO figures.
In the UK, the CCC’s analysis suggests that the most cost-effective route to fulfilling the UK’s obligations under the Climate Change Act requires a contribution from aviation. They say that aviation emissions should be no higher in 2050 than they were in 2005. The projected improvements in fuel efficiency will allow for a 60% increase in passenger demand between 2005 and 2050.
Options for further mitigation
Better planning could help to mitigate the impacts of noise and air pollution, by ensuring new airports and runways are not built next to densely populated areas. Construction of new high speed rail links will reduce some of the demand for shorter, internal flights.
Further development of alternative fuels is also possible. ‘Solar Impulse’, a plane powered entirely by solar panels fixed to the aircraft, recently completed a circumnavigation of the world. But solar technology is not currently capable of powering a large, commercial plane.
In a 2009 report, Policy Exchange argued that bio-jet fuels had significant potential to replace standard kerosene jet fuel. They are an advanced biofuel that does not compete with food production and that offers greater life-cycle carbon savings than the first generation biofuels used in road transportation. Moreover, the volume of feedstocks required to meet all EU demand for jet fuel in 2050 is feasible, needing an area of land just slightly larger than Wales.
Ultimately, reducing CO2 emissions from aviation will be dependent on securing an international agreement. Without broad buy-in from the countries with big aviation sectors, there will just be ‘carbon leakage’, whereby emissions are not cut but displaced to countries with less stringent regulations.
The ICAO is expected to agree in Autumn 2016 on a ‘market-based measure’ to cap net emissions at 2020 levels. A market-based measure allows industry to pick from a range of options for reducing emissions. These include levies, offsetting schemes, and emissions trading. However, reports from the talks this week suggest that such an agreement may only be voluntary initially, with an option for a compulsory limit five years later.
Since 2012, the UK’s international aviation emissions have been included within the EU’s Emission Trading Scheme (ETS), which allows carbon emitters, such as airlines, to buy and sell permits for their emissions. As with many environmental regulations, the UK’s future involvement in this scheme is now in question. However, it is worth noting that all EEA countries are currently participants in the EU ETS.
There is strong evidence of aviation’s importance to the UK economy, as it contributed £18 billion of annual economic activity and directly employed 220,000 people in 2013. Reducing demand for air travel, therefore, is likely to carry a significant economic penalty. For this reason, it is essential that a long-term, international solution to the environmental harms of aviation is found, and quickly commercialised.