Aviation Emissions and Climate Change – An Overview

6.3% of British CO2 emissions were from aviation in 2005.  This translates to around 13% of Britain’s climate change effect being from aviation (domestic and international).

[In fact, if UK citizens are considered, leaving the country and then returning, rather than just departing flights from UK airports, the figure is more like 16 -17% of the UK’s climate change effect being from aviation].

Aviation accounts for around 2% of the CO2 emissions globally.  That is just the CO2 only.

The UK’s aviation accounts for around 0.1% of global CO2 emissions.

Aviation contributes around 3.4% of the EU’s CO2 emissions.

50% more emissions from global aviation expected by 2020, assuming fuel efficiency improves by 50%

240.7m passengers used British airports in 2007.  In 2007 this was forecast to rise to 470m by 2030.  In January 2009 the DfT forecast UK national passenger demand, unconstrained by airport capacities, to rise from 241mppa in 2007 to 465mppa in 2030.  There are a range of forecast figures with different assumptions in the DfT January 2009 UK Passenger Demand and CO2 Forecasts.

1.2 tonnes of CO2 (approximately) are emitted for each economy passenger return London-New York flight

What is the real climate impact of flying and what can we do about it? (BBC info)

28th May 2009    The BBC has produced an excellent page, setting out a great deal of information on the climate change impacts of aviation.   Well worth a look. It is at: http://www.bbc.co.uk/bloom/guides/flying.shtml

Click here for more…

If flying expands as much as the UK Government predicts …

Government’s climate Change Policy

The Government has a climate change target to cut overall UK carbon emissions by 80% between 1990 and 2050.  Its own research states that this will be impossible if aviation is allowed to carry on expanding at the present rate.  For aviation to be allowed to emit as much CO2 in 2050 as it did in 2005, most other sectors of the UK will have to cut their emissions by 90% by 2050.  The independent Tyndall Centre for Climate Change Research estimated that, unless aviation emissions were controlled effectively, with business- as-usual growth, they could account for up to half of the UK’s total emissions target by 2050, cancelling out savings made by individuals and other industrial sectors.  .

Aviation’s contribution to climate change globally

What % of the UK’s carbon dioxide emissions are from aviation?

Do planes produce more CO2 than other modes of transport?

Air travel can contribute a high proportion of any individual’s carbon footprint, as a plane journey takes so little time to cover a huge distance.  Though the emissions of CO2 per person per kilometer by plane may be only slightly worse than the same journey by car (excluding the doubling due to radiative forcinc), not many people bother to drive 10,000 miles to their holiday destination, or if they did, it would take them weeks rather than hours.  It is quick and easy by plane, with the same amount of carbon being emitted in a couple of hours of plane trip, as would take weeks by car.

The charts on page 41 shows the emissions of CO2 per passenger kilometre.   CE Delft concludes that CO2 emissions by aircraft are anything from 3 to 10 times higher than rail for medium distance journeys of 500km. For longer journeys of 1,500km, air is a little better in terms of emission per passenger km, but still about 2 to 6 times worse than rail.

There is a lot of useful information in the article below, from Travel Weekly, 19.1.2007 

Aviation and Climate Change – a Q&A guide

Aviation and climate change: Q&A guide
(19 January 2007)

Ryanair claims to be Europe’s “greenest, cleanest airline”. UK environment minister Ian Pearson calls the carrier “irresponsible”. Who is right?

It depends on your point of view. Ryanair operates a fleet of predominantly new aircraft that produce significantly less carbon dioxide than older models and is committed to a continual fleet renewal programme as it expands.

Aircraft fuel efficiency improved 20% in the past decade and almost 5% in the last two years, according to the International Air Transport Association, cutting emissions by a comparable amount.  The latest Boeing and Airbus models should bring further improvements.

Carriers such as Ryanair, and tour operators’ charters, also fly with more bums on seats than traditional airlines, so the emissions per passenger are lower – and area fraction of those produced by long-haul business and first-class passengers.

However, Ryanair is expanding rapidly, as are other airlines. It aims to double in size by 2012, so its total emissions will soar above improvements in fuel efficiency.

But it is Ryanair’s threat to boycott the European emissions trading scheme that provoked the environment minister’s outburst.  The Government has put all its eggs on aviation emissions in this one basket, which airlines are set to join in 2011.

They will trade carbon dioxide allowances with other industries and have to pay out if they want to expand.

Ryanair boss Michael O’Leary also delights in challenging all things green. He referred last week to “environmental hysteria” and said: “People are being scammed.” O’Leary enjoys the publicity and other carriers are happy to see him take the flak.

There are different figures for air travel’s contribution to climate warming.  What is it and what is the problem?

Aviation accounts for 2% of worldwide CO2 emissions, and 3.4% of the European Union’s.

UK air travel is responsible for 0.1% of the world’s total emissions, so airlines point out it would make little difference if everyone stopped flying.  However, flights do produce 5.5% of total UK CO2 emissions [6.3% in 2005] – reflecting the importance of Heathrow as a hub and the number of over-flights.

The problem is that air travel is the fastest-growing source of greenhouse gases and its expansion risks undermining progress in reducing emissions in other areas.

The international Kyoto Protocol of 1997 commits EU members to cut CO2 emissions by 8% below the level of 1990 by 2012.  The UKGovernment has acknowledged a need to cut emissions by 60% by 2050.  In fact, scientists suggest a 90% cut may be needed, but argue it is not achievable.

Whitehall accepts the UK cannot meet its target without cutting aircraft emissions. The Government predicts UK passenger numbers will rise to 476 million a year by 2030, taking aviation emissions to more than 4.5 times their 1990 level.   European Commission figures suggest a return, UK-Thailand flight for two produces more CO2 than the average new car will in a year.

Aircraft emit CO2, the gas responsible for about 80% of global warming.  But they also create water vapour at high altitude which may be even more damaging.  The Government suggests this may exacerbate the warming effect of air travel by a factor of 2.4, although the International Panel on Climate Change that reports to the United Nations suggests a factor of 2.7. [The UK Government now uses a figure of 1.9, while waiting for better clarity of the science].

Either way, it is a worry.

Airlines believe they are being singled out for unfair criticism. Are they right?

They have a case. Other sectors pose a much greater problem. Power stations produce 39% of EU emissions and roads are to blame for 22%.

Cutting the use of cars and trucks, switching from fossil fuels in power generation or capturing and burying CO2 from power plants would make a far bigger contribution to cutting emissions than anything airlines can do.

And there are plenty of other polluters to tackle. China is building coal-fired power stations at anastonishing rate – although its production of CO2 per person remains at one-third of that in the EU. Global deforestation is adding CO2 and reducing the amount that nature can absorb. Methane produced by cattle and seeping from rubbish dumps is exacerbating global warming, with a short-term impact many times that of CO2.

The industry has every right to be indignant about the doubling of Air Passenger Duty, which the Chancellor attempted to justify on environmental grounds.  A Treasury spokesman told Travel Weekly:  “It may provide an incentive to take holidays at home and to business travellers to consider using the train.”  Yet the Government’s Aviation White Paper of 2003 acknowledged that taxing flights would be unlikely to cut demand.

Airlines do get off lightly on tax. If aviation fuel (kerosene) was taxed at the same rate as petrol, airline fuel costs would quadruple. At the moment, kerosene is not taxed at all.

The industry should be aware it is not alone in arguing other sectors should be tackled first. European steel bosses say the same thing, pointing out EU steel plants account for just 1% of global CO2 emissions.

Tony Blair says technology is the answer. What’s wrong with that?

Technology can certainly help, as continuing improvements in aircraft engine efficiency show. However, its contribution may be much more limited in the case of flying than Blair suggests.

Despite efficiency improvements, total emissions from UK aviation rose 79% between 1990 and 2004. It is estimated the industry’s expansion will outstrip efficiencies by 3% a year for the foreseeable future, with the Government expecting UK passenger numbers to double by 2030.

The Aviation White Paper suggested a 50% reduction in CO2 emissions from aircraft may be possible by 2020. But MPs on the Commons Environmental Audit Committee described this claim as “misleading”, pointing out it depends on technologies that do not yet exist. And many airlines will continue to fly elderly, more-polluting aircraft unless they are forced to scrap them.

Developing an alternative fuel won’t be easy because of the need to operate at very low temperatures. Existing biofuels thicken when cold and would pose a safety problem. So would hydrogen. Using hydrogen as a fuel would also pose an emissions problem, since it would produce high volumes of water vapour. In its 2004 report Aviation and Global Warming (pdf) the Department for Transport concedes: “There is no viable alternative currently to kerosene.”

The Virgin Group and US space agency NASA are working on prototype aircraft that might fly far higher than today’s aircraft, in the stratosphere. But a Government Royal Commission noted scientists’ concerns that emissions at such altitude may be 5.4 times more damaging than at ground level.

What other possible solutions are there?

Air traffic control improvements could cut emissions by 10%-12%, reducing stacking over busy airports, shortening routes and allowing aircraft to come into land in a fuel-saving continuous descent approach (CDA).

Airlines could reduce emissions further by rationalising operations to cut the number of empty seats.

The European emissions trading scheme ought to play a part,although restricting it for at least the first year to flights within the EU will exclude more than 60% of aircraft emissions in Europe. Most airlines are in favour. In the words of a British Airways spokesman, a failure to include carriers in emissions trading “would be very dangerous. It would increase the political pressure to take other measures against airlines.”

However, there are doubts that it will produce any cut in emissions.  The first year of the scheme in 2005/2006 proved disappointing.  The market price of carbon collapsed and the scheme led to no overall cuts in emissions.

Carbon offsetting is becoming popular as a way for individuals to show their concern about the impact of flying on the climate. But there are limits to its effectiveness. Many schemes involve planting trees to absorb carbon dioxide, which is only absorbed for the lifetime of the tree. As forests mature they release carbon dioxide. Now a committee of MPs plans to investigate offsetting schemes to see if they really do what is claimed.

Virgin chairman Sir Richard Branson has joined environmental groups in suggesting people should not fly if there are cleaner alternative forms of travel available. “People should think twice before flying domestically,” he says.

Leave aside the fact that Virgin Trains forms an important part of Branson’s business, it is not true that railways will always be less polluting than flying. A London-Manchester flight currently produces 13 times as much CO2 per passenger as a rail journey on the same route. But faster trains will cut the savings. At 220mph, a London-Edinburgh train journey would produce more CO2 per passenger than the comparable flight.

Aren’t there still doubts about whether the world is warming, whether humans are responsible, and whether this is a bad thing?

No, the evidence on these questions is now overwhelming. The waters have been muddied by a handful of dissidents, often non-scientists, who receive substantial funds from sections of the fossil fuel industry and a sympathetic hearing from the US government.

The real arguments lie elsewhere. Climate scientists are debating how far and how fast the Earth will heat up, assuming the warming is gradual – as predicted by the IPCC. Many now argue this model is wrong and future warming will be sudden and extreme, as rising temperatures trigger changes in climate systems and release vast quantities of greenhouse gases trapped beneath oceans, ice and permafrost.

The EC warned last week: “Time is running out.”