To fly or not to fly?

We all know the truth: flying is bad for the environment. But is that really the truth? Here our expert offers advice, and answers those vital questions

Richard Hammond
01 April 2007

How bad for the environment is flying?

One return flight from London to Sydney emits about 5 tonnes of carbon dioxide (CO2) – that’s about half the average person’s annual carbon footprint. It’s that bad. According to the Stern report produced for the UK government in 2006, total annual CO2 emissions from aviation is about 600-700 million tonnes – a 2-3% share of global CO2 emissions.

But this share is likely to grow substantially over the next 20 years because of the huge growth planned in aviation worldwide. Britain’s CO2 emissions from aviation doubled between 1990 and 2000 and are expected to double again by 2030. Aviation is currently the fastest-growing contributor to CO2 emissions.

Is flying always worse than other forms of transport?

Yes, just about. The carbon footprint of any form of transport depends on a combination of factors, such as the type of engine, the number of passengers, the length of the journey, the speed and the type of fuel or power.

Eurostar claims that its London to Paris return trip produces about 0.01 tonnes of CO2 per passenger, whereas a return flight (Heathrow to Paris) produces ten times this amount. Compared with driving a car, however, the emissions produced by flying are about the same, kilometre for kilometre. For instance, a return trip from London to Bilbao in a 2L petrol engine car produces 0.26 tonnes of CO2, while a return flight produces 0.28 tonnes. By comparison, the same journey by train produces around 0.1 tonnes, while a ferry from Portsmouth generates 0.09 tonnes.

Is flying with some airlines better than others?

The no-frills airlines claim they are more environmentally friendly than ‘legacy’ airlines because they operate newer planes that are more fuel efficient.

Hugh Somerville, from the aviation industry’s environmental taskforce Greener by Design, says: “Newer airlines have younger fleets, and they also operate with more than 90% load factors.” So the carbon footprint per passenger is far less than that of a plane with only half a load.

However Jeff Gazzard, coordinator of lobbying group GreenSkies, says the enormous growth of no-frills airlines has contributed to “an inexorable rise in pollution” that far outweighs any gains provided by aircraft efficiency and high load capacities.

Does flying deserve to be labelled the big polluter?

The problem with flying is that it often involves travelling huge distances in such a small amount of time, so it is easy to notch up a huge carbon bill from a single journey. Furthermore, CO2 emitted at high altitude has a greater affect on climate change than the same amount at ground level. Also, at high altitude planes produce contrails (trails of water vapour condensation), which have a ‘radiating force’ that contributes significantly to global warming.

Jeff Gazzard recommends multiplying a plane’s CO2 emissions by a factor of 2.7 to take into account the effects of other non-carbon emissions, such as contrails, in order to find the overall environmental impact of the flight.

Is flying short haul worse than long haul?

Long-haul flights emit huge amounts of CO2 – and until aircraft use more fuel-efficient technologies there’s no getting away from that ‘inconvenient truth’. Short-haul flights don’t reach the high altitudes of a long-haul flight where contrails are produced and carbon exerts its more harmful effect. However, the fuel used for take-off and landing is a high proportion of the total amount used on a flight, so it doesn’t take many short flights to produce as much CO2 as one long-haul flight.

Is there a better time of day or year to fly?

In terms of the amount of carbon emitted, no. Carbon remains in the atmosphere for decades, perhaps even 100 years, regardless of when it is pumped out of a plane while flying. However, it is better to avoid flying during the night because of the effect of a plane’s contrails.

According to Dr Piers Forster at the University of Leeds, the warming effect of contrails is doubled at night because they continue to trap heat from the earth but don’t reflect the sun’s rays back into space as they do during the day.

It is also better to avoid flying in winter as planes produce more of these contrails in cold temperatures and high humidity. Flights between December and February account for less than a quarter of the total air traffic, yet according to Forster they contribute half of the aviation industry’s annual contribution to climate warming.

Should the aviation industry be allowed to grow?

It is predicted that if the UK’s aviation industry is allowed to grow unchecked it will account for 31% of all UK greenhouse gas emissions by 2030. According to The Tyndall Centre for Climate Change Research, the UK will have to curb aviation growth, otherwise all other sectors of the economy will be forced to become carbon neutral in order to meet the government’s target of a 60% reduction of all CO2 emissions by 2050. However, the aviation industry says this would have a detrimental impact on the UK economy. “Aviation should be allowed to grow within the overall framework of the economy – there’s no point in the UK making an example of itself and sacrificing its economic position,” says Hugh Somerville.

Unless greener technologies are introduced throughout the aviation industry on a global scale, a genuine commitment to reducing CO2 emissions can only come by implementing tighter controls over aviation growth. The EU ETS and personal offsetting schemes should really only be supplementary to this; if the world does nothing to limit aviation’s impact on climate change, we will all pay the price.

Is offsetting a practical solution?

It’s far better to look for greener ways to travel than carry on polluting and hope that offsetting will justify the damage. However, donating to a good offsetting scheme is better than ignoring the issue altogether, and does provide a way to counterbalance your carbon footprint in the absence of cleaner technologies. You can offset your emissions on this website.

Another interesting site is, which allows you to click your departure point and destination on a world map and see detailed calculations for your emissions. compares emissions from flights, cars, ferries and trains.

If we stop flying, will the economies of developing countries suffer?

Many of the world’s poorest countries rely on tourism and have few other economic alternatives. Tourism is now the principal export earner for a third of developing nations. In developed countries, too, tourism is valuable for conservation and rural development. If you consider how best to use your flight, and choose to go on trips that bring tangible benefits to the destination – wherever it is in the world – you can make a significant difference to conservation and to local communities.

Would paying higher ticket prices – perhaps forced by a tax on aviation fuel – make a significant difference?

“The price of a plane ticket must reflect the environmental cost of the flight,” says Mark Kenber, policy director of the international consortium The Climate Group. Unless the airlines are forced to do this, Kenber says he “can’t see there is a real incentive for airlines to look at bio-fuels and energy-efficient planes”.

But by how much should the price of a ticket rise? Hugh Somerville thinks only a “massive” one-off increase will significantly reduce air travel, while Jeff Gazzard wants to see a tax per km of around 3.6p (increased annually in line with inflation), which would be collected in a similar fashion to the existing Airline Passenger Duty (APD), whereby passengers foot the increased cost of the ticket. He estimates this “congestion charge of the skies” would reduce aviation growth by about half, reducing the current forecasted growth of 500 million by 2030 to around 300 million.

We think…

At Wanderlust, we aim to promote alternatives to flying where feasible, but when flying is the only realistic option, we believe the social, economic and conservation benefits of responsible travel outweigh the effects of CO2 emissions. We also make a contribution to the offsetting firm Climate Care for every flight taken specifically for the magazine.

Explore More

More Articles