Don’t forget about Heathrow

On Monday 13th July, thirteen Plane Stupid activists staged a protest on London Heathrow’s northern runway. The message was simple: there is a choice between preventing climate change and building new runways – we cannot do both. Aviation is incredibly damaging to the climate and its unfettered growth will jeopardise the UK’s chance of meeting its ambitious and legally binding climate targets. The 2008 Climate Change Act stipulates that an emissions reduction of 80% from 1990 levels must be made by 2050. This will not be possible if airports are actively expanded. Together with many other groups, Plane Stupid has been part of the movement campaigning against the third runway at Heathrow since it was first proposed. We have prevented the third runway from being built before, and we will do it again. What is more, we will oppose the expansion of airports everywhere, not just at Heathrow. Put simply, we’re in it for the long haul. And finally: this is about the affluent frequent fliers who fly multiple times a year for short leisure trips. There is sufficient existing capacity to support business flights and family holidays; we just do not need another runway to facilitate the very wealthy jetting off every other weekend to holiday homes and on shopping trips. We have a choice to make, and we want to make sure that that choice is the right one.

credit: Plane Stupid

credit: Plane Stupid

Climate motivations

The primary motivation for the protest at Heathrow was to prevent emissions. However, an expected happy side effect was that it would bring climate change back into the discourse around airport expansion. It was also timed to coincide with the release of the Davies report, the culmination of a three-year review into UK airport capacity. In this report, the Airports Commission notes that “the environmental impacts of aviation are significant” (Airports Commission, 2015: 167), but nevertheless goes on to recommend an expansion of airport capacity in the Southeast. Aviation currently accounts for ~7% of UK emissions, and this is likely to increase, partly because the sector is continually expanding, and partly because emissions from other sectors are decreasing to meet climate targets. Heathrow is currently responsible for more CO2 emissions (16.584 Mt CO2e in 2012) from scheduled passenger flights than any other airport in the world (Southgate, 2013). If total aviation emissions are capped at 37.5 Mt CO2e, as suggested by the Committee on Climate Change and the Airports Commission, aviation would account for 25% of total UK emissions in 2050 (CCC, 2009; AEF, 2015; Airports Commission, 2015). The DfT (2013) estimates that aviation emissions could reach 52.1 Mt CO2e by 2050 if allowed to increase unchecked, though the Davies Report and Committee on Climate Change (CCC) both state that emissions cannot exceed the 2005 level of 37.5 Mt CO2e. Anything higher than this would make meeting our climate targets economically suboptimal and carry a high level of risk (AEF, 2014). This means that while every other industry, and the UK as a whole, must decrease emissions based on a 1990 baseline, the aviation industry is effectively allowed to increase emissions and maintain them at 2005 levels (which equates to a 120% increase on 1990 levels). This means that other sectors would have to reduce emissions by 85% on 1990 levels, a figure which is “at the upper end of what is currently expected to be deliverable” (Airports Commission, 2015: 66), and which the CCC considers a “realistic but ambitious goal”. This is a very ambitious target. To illustrate: according to government statistics, in 2013 the UK transport sector as a whole emitted 157.7 Mt CO2e. Of this, 116.8 Mt was generated by domestic transport (DfT, 2014). This figure has fallen from its peak at 177.9 Mt CO2e in 2007 at a rate of 1.9% per annum on average. At this rate of decline, by 2050, transport would still account for 77.8 Mt CO2e, which is 48% of the total UK target 161.88 Mt CO2e that we must meet under the Climate Change Act (figures from DECC, 2015). This is just the transport sector. There are many other sectors that also emit considerable amounts of greenhouse gases, such as energy generation, heavy industry and agriculture. To think that these remaining sectors combined could emit just 84.08 Mt CO2e is certainly ambitious, even if the emissions cuts achieved increase year on year, as assumed by the successive five year carbon budgets legislated by the 2008 Act.

credit: Plane Stupid

credit: Plane Stupid

The 37.5 Mt CO2e target for aviation does not include the non-CO2 impacts of aviation. Aviation isn’t just an incredibly carbon-intensive mode of transport, it is particularly damaging when you consider the emissions of other greenhouse gases, especially at the heights at which aircraft cruise. Another way of measuring the effect of sources or sinks of carbon to the atmosphere is by their radiative forcing (RF). This is defined by the Intergovernmental Panel on Climate Change (IPCC) as the “change in energy flux caused by a driver, and is calculated at the tropopause or at the top of the atmosphere” (IPCC, 2013: 13). It is expressed in Watts per square meter (W m–2) and can be loosely interpreted as the heating or cooling effect of something, where a positive RF causes warming, and a negative indicates cooling. Lee et al. (2009) estimate that aviation’s RF is 55 mW m-2, excluding the effect they have on high-altitude cirrus clouds, and Kahn-Ribeiro et al. (2007) estimate that aviation alone accounted for 3% of anthropogenic radiative forcing in 2005. Aircraft fly in the stratosphere (generally higher than 15km above the ground), which means that they release pollutants at a level where they would not naturally be found, even at very low concentrations. The stratosphere is very dry. The release of water vapour from aircraft exhausts into the stratosphere therefore catalyses the formation of stratospheric clouds, which have a very strong climate effect. Although uncertainty is relatively high regarding their impact, the IPCC estimate that they have a small positive effective RF (0.02-0.15 W m-2). Emitted particulates and gases such as NOx (shorthand for all nitrogen oxide species) act as ‘cloud condensation nuclei’, which are small particles onto which water condenses. This triggers a chain reaction whereby more and more water condenses onto the growing droplets, until they are so large and numerous that a cloud forms. NOx emissions have also been linked to ozone depletion, which is another serious atmospheric problem. There are many other local environmental ramifications. These include increased noise and air pollution, which cause significant damage to the health, education and welfare of local residents, water pollution and flood risk, and impacts on biodiversity. Although the Airports Commission suggests that the indirect effects on wildlife at the West London Waterbodies RAMSAR site will be minimal, the increased noise and damage to habitats in the local area will likely have unforeseen negative consequences for biodiversity due to the complex interactions within ecosystems.

credit: Plane Stupid

credit: Plane Stupid

“No ifs, no buts”

Plane Stupid is part of a movement that has stopped a third runway at Heathrow before, and it will do it again. In 2009, David Cameron vowed not to expand Heathrow, “no ifs, no buts”. Fast-forward six years, and the party that led the coalition that claimed to be the ‘greenest government ever’ is actively seeking to increase airport capacity in the Southeast, despite the need to reduce carbon emissions. Even the Davies report acknowledges that without “strong action” to reduce emissions in aviation, airport expansion would make it more challenging to meet our climate targets. This is because air travel is the most carbon intensive mode of transport, and it is difficult to change this. Decarbonising the aviation sector is particularly challenging because the required energy density of fuel is so high – to stay in the air, you must keep weight as low as possible, so the fuel used must supply a lot of energy per unit of volume. This means there are few practical alternatives to petroleum-based fuels.

Davies examines two options to limit aviation emissions: an overall carbon cap at 37.5 Mt CO2e, or carbon trading to limit emissions to the same level. They suggest that a “substantial package of measures would be needed [at Heathow], including for example the same carbon price [as in the CCC report] and significantly higher biofuels usage, plus a range of operational efficiency improvements, all of which represent technologies or practices understood today but as yet to be implemented on a wide scale” (Airports Commission, 2015: 139). Biofuels are frequently heralded as the primary carbon-limiting solution for aviation, but government figures suggest that these may account for just 2.5% of fuel use by 2050 (DfT, 2013). The new generation of biofuels is not yet commercially viable, and comes with a whole host of other associated environmental issues, such as the trade off between food vs. fuel production on productive agricultural land. The operational efficiency improvements mentioned, such as air traffic management, can reduce emissions slightly, but the emissions savings from increased efficiency will likely be quickly offset by higher numbers of flights (Bows-Larkin, 2013).

The primary way to reduce emissions from aviation, and of the UK, is by reducing demand. Historically, massive efficiency improvements and technological advances were made in aviation in the 1950s and 1960s, with additional improvements in the 1990s-2000s (IEA, 2012). This offset the surge in demand somewhat. However, historical trends may not continue as diminishing marginal returns are achieved and the easiest mitigation options (the ‘low-hanging fruit’) are adopted first. Indeed, according to the Aviation Environment Federation (2014), fuel efficiency improvements have plateaued. Either way, rising demand is projected by e.g. Kahn-Ribeiro et al. (2012) to offset any savings made by future efficiency improvements and technological change. Many authors, such as Anable et al. (2012) and Bows-Larkin (2013) suggest that demand management (read: reduction) is the most feasible way of reducing aviation’s emissions. It is a difficult truth to stomach, but the truth is that we must now dramatically curb demand for aviation, and that means eliminating unnecessary flights. Oh, and not building any new runways.

The Airport Commission’s carbon trading argument hinges strongly on some key assumptions. They assume a carbon price of £330/tonne in 2050 to cap emissions at 37.5 Mt CO2e, while the CCC (2009) assumes that £200/tonne could reduce demand increases to 115%. Contrast these with the current European carbon price, which reached a maximum of €32 (£22.6) per tonne in 2006, and the benchmark price which was trading at €7.3 (£5.2) per tonne in May this year (Chestney, 2015). The European Emissions Trading Scheme (EU ETS) covers just a quarter of EU flights because it only includes flights within the EU (AEF, 2014); the remaining 75% either originate or terminate outside the EU and are not included. Although the International Civil Aviation Organization (ICAO) has accepted the inclusion of aviation in a global market-based emissions reduction mechanism from 2020, the slow progress and reluctance of governments and industry to include aviation in global carbon and climate policy like the Kyoto protocol suggests that it might take a while to for aviation carbon trading to – errr – take off. With this in mind, it looks increasingly unlikely that a high enough carbon price will be achieved in time for 2050.

credit: Thomas Nugent [CC BY-SA 2.0 (], via Wikimedia Commons

credit: Thomas Nugent [CC BY-SA 2.0 (, via Wikimedia Commons

Frequent fliers

Flying is predominantly a preserve of the wealthy. 70% of flights are taken by the richest 15% of the UK population, and globally, only 5% of the world’s population have ever flown. This underlines the point that flying is a luxury, unaffordable for the masses, that entrenches the existing inequality created by climate change. The poorest people (both globally and within countries) are likely to be hit hardest, and hit first, by climate change. The poorest countries are least resilient to the negative effects of climate change, which include increased flood risk, sea level rise and extreme weather events. The nature of these effects will disproportionately affect people who rely on natural systems for their livelihoods, such as farmers, indigenous forest peoples and fishers. Low-lying countries like Tuvalu, the Maldives and Bangladesh are among the poorest in the world, and rising sea levels will decimate the economies of these nations, and by extension, the livelihoods of their citizens. Meanwhile, airport expansion is being driven by demand for short haul flights to destinations favoured by affluent frequent flyers. A 2013 HACAN report found that 20-25% of flights from Heathrow are short haul. Further, nine of the top ten destinations are short haul, and the most distant of these is New York. The remaining nine are all British or European destinations, with Dublin and Edinburgh ranking second and sixth.

Contrary to what the government might want you to believe, business and trade are not driving demand. Business flights are in decline, and have been since the beginning of the century. This is partly a result of better technology: for instance videoconferencing is on the increase, so there is less and less need for businesses to send representatives in person. Airfreight is an expensive and inefficient method of transporting goods, and 80% of international freight is moved by sea (Kahn-Ribeiro et al., 2012). Airfreight is highly sensitive to economic indicators like GDP, which demonstrates that it is only economically viable in a ‘healthy’ economy. The argument based on the benefits of Heathrow for cargo movements is therefore highly flawed.

The carbon price argument means that demand falls because it costs too much to fly. This means that the inequity associated with aviation would be increased, rather than reduced – the richest who fly most will still be able to afford it, while the those who fly only occasionally will be priced out. The Davies commission report consistently highlights the need for increased connectivity, benefits to passengers and the local economy, but really, they are proposing building this new runway for the rich. An elevated carbon price would mean airlines would pass costs on to passengers, prices for airline tickets would soar (excuse the pun) and the average person would be priced out of the market.

credit: Plane Stupid

credit: Plane Stupid

There is no credible case for airport expansion in the Southeast. London is the top market in the world by origin and destination measures (Airports Commission, 2015) and has no fewer than five airports (or six if you include ‘London Southend’). It is ludicrous to propose that we need additional airport capacity. The drive for expansion is part of the government agenda to maximise profit, with little regard for our environment, social justice, or ability to prevent disastrous climate change. The only thing that building more runways will do is to line the pockets of those brokering the deals. Airport expansion will prevent us from meeting our climate targets, which are already going to require a concerted effect to hit. The choice is simple: a future, or a quick buck for the rich. We felt compelled to act in order to make sure the scales are tipped in the right direction.


Aviation Environment Federation (2014) Airports Policy Briefing: Airport expansion and climate change

Aviation Environment Federation (2015) Climate Change and Aviation (online) available at: accessed 20/07/15

Bows-Larkin, A. (2013) Pathways to low-carbon international transport: a comparison of shipping and aviation. In: Paper delivered at the Low Carbon Shipping Conference, London

Bows-Larkin, A. (2014) All adrift: aviation, shipping, and climate change policy. Climate Policy, (ahead-of-print) 1-22

Chestney, N. (2015) EU carbon market expects price rise for first time in four years. Reuters. Published 26th May 2015, available online at accessed 24th July 2015

Committee on Climate Change (2009) Meeting the UK aviation target – options for reducing emissions to 2050

Department for Transport (2013) UK Aviation Forecasts. DfT, London

Department for Transport (2014) Total Greenhouse Gas emissions from transport (ENV04) Transport, energy and environment statistics (Statistical dataset). DfT, London

Dessens, O., Anger, A., Barker, T., & Pyle, J. (2014) Effects of decarbonising international shipping and aviation on climate mitigation and air pollution. Environmental Science & Policy 44 1-10

IEA (2012) Energy Technological Perspectives 2012: Pathways to a clean energy system. International Energy Agency, Paris

IPCC (2013) Summary for Policymakers. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., Qin, D., Plattner, G.-K., Tignor, M., Allen, S.K., Boschung, J., Nauels, A., Xia, Y., Bex, V. & Midgley, P. M. (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA

Kahn-Ribeiro, S., Kobayashi, S., Beuthe, M., Gasca, J., Greene, D., Lee, D.S., Muromachi, Y., Newton, P.J., Plotkin, S., Wit, R.C.N. & Zhou, P.J. (2007) Transportation and its infrastructure. In: ‘Mitigation of Climate Change’ Fourth
Assessment Report Working Group III, Intergovernmental Panel on Climate Change. Cambridge University Press, UK

Kahn-Ribeiro, S., Figueroa, M. J., Creutzig, F., Dubeux, C., Hupe, J. & Kobayashi, S. (2012) Energy End-Use: Transport. In: Global Energy Assessment – Toward a Sustainable Future. Cambridge University Press, Cambridge, UK and New York, NY, USA and the International Institute for Applied Systems Analysis, Laxenburg, Austria

Southgate, D. (2013) Aviation carbon footprint – Global scheduled domestic passenger flights – 2012

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About shakkka

Londoner, climate scientist, extremist. All views are my own.

One response to “Don’t forget about Heathrow”

  1. bsteel2014 says :

    Reblogged this on Sutton Greens and commented:
    Meanwhile down at Heathrow a very important battle is again being fought by a few brave activists, taking on the might of the powerful and destrcutive airport expansion lobby. Support them!

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