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What Is Carbon Offsetting And How Does It Work?


Every time I book a flight I get invited to pay extra to 'offset my carbon footprint' from the flight. How does that work and where does my money go? Adrian Denny, Luton

Our Answer

In an effort to make flying less harmful to the environment, many airlines now offer their passengers a chance to pay extra to reduce their carbon footprint. But you're right Adrian, the information available about carbon offsetting when you're booking your flight is often limited or confusing. So, here is everything you need to know:

What Is Carbon Offsetting?

The burning of fossil fuels, like the aviation fuel used in aeroplanes, emits greenhouse gases, which are very harmful to the environment. Carbon offsetting is the means by which you invest back into the environment and counteract the greenhouse gases that you have created with your flight.

For example, if you have driven to the airport then boarded a flight, you will have used fossil fuels for the petrol in the car, and then the aviation fuel on your plane. Both of those fuels release carbon dioxide into the atmosphere. To offset the environmental impact of the carbon dioxide your travel created, you can invest in a project that either produces energy that is considered non-carbon producing, such as a hydroelectric dam, or a project that produces oxygen, such as tree planting.

Although they are called 'carbon offsets', carbon offsetting relates to the reduction of all 'greenhouse gases', not only carbon dioxide. The common greenhouse gases that your carbon offset may combat are carbon dioxide, methane, nitrous oxide, ozone gases and water vapour.

How Is Carbon Offsetting Calculated?

Carbon offsets are calculated by determining the amount of greenhouse gas a particular flight gives off in metric tons.

In other words: 1 metric ton of carbon dioxide (or any other harmful gas) = 1 carbon offset.

Once the number of metric tons of CO2 has been measured, passengers are given the chance to make a financial contribution. Your financial contribution will be relative to the amount of CO2 emited, given the number of passengers on board and the size of the plane.

However, it is important to remember that calculating your true carbon footprint is incredibly difficult. The ripple effect of even a small action, like buying a bottle of water on a flight, could have a long reaching effect depending on where the bottle was made, what materials were used, how it was stored and how it was transported.

Where Does My Money Go?

Your money is invested in various environmental programmes. Airlines use carbon offset payments to fund programmes which develop renewable energy sources, like solar power and wind farms, as well as research into energy efficiency.

You can ensure that your carbon offset purchase is having the impact you hope for by checking that your airline invests in audited projects certified by bodies, for example the U.N. Clean Development Mechanism.

British Airways, for example, invests in carbon emission reduction projects that follow the guidelines of the Kyoto Protocol . The main projects they invest in are hydro-electric plants and wind farms in Asia. They also try to invest in projects that have social and economic benefits in small communities.

Do They Really Make A Difference?

Many of the projects that airlines invest in promote the increased development and introduction of renewable and clean energy. This is generally considered to be a worthwhile cause, as it is common knowledge that fossil fuels are going to run out and that the world's major energy resourcing has to evolve quickly.

Don't My Airport Taxes Pay For Them Anyway?

Airport taxes go towards many areas, such as government excise, baggage handling, airport facilities, security and fuel surcharge (a result of higher fuel prices). Although Air Passenger Duty has been touted as a "green" tax it has not been confirmed exactly how the money is spent and if the carbon footprint of the flight has been offset from your duty charges.

Am I Obliged To Invest In Carbon Offsets?

No, it is totally voluntary if you are a member of the public wishing to make a difference to the environment. If you are a business, government legislation may require you to offset your emissions, depending on your sector.

Can I Claim Gift Aid Or Any Tax Benefits?

Yes you can if you are a UK tax payer.

Why Do Carbon Offsets Vary In Price?

Carbon offsets available to you vary in price for a number of reasons, the most important are:

  • The complexity of the neutralisation process i.e. extraction of methane gas from a mine is an expensive but important process in the overall environmental impact
  • How well the project is recognised by authorities
  • Wider social and environmental elements. In other words, are the correct procedures being followed?
  • The number of organisations involved in the selling of the carbon offset

Are Some Projects A Better Investment Than Others?

Some projects, such as planting a tree, could take decades to directly neutralise your carbon footprint and so may not be the best investment. However, even planting a tree has some immediate benefits, for example the stabilisation of soil, the benefit to wildlife habitats and its usefulness as a sustainable material i.e. for housing. Other projects, such as an investment in solar power may have a more immediate effect in saving energy. However, you still need to consider the carbon footprint of manufacturing the solar panels.

If It's So Easy Why Are Global Carbon Levels So High In The First Place?

Essential Travel asked an expert in the field, Ian Mitchell this question and he had the following to say:

"The challenge facing all of us is that as the global economy grows, the world as a whole continues to consume more energy and produce more greenhouse gases per head. Carbon offsetting is just the beginning of a more responsible approach to global sustainable development. There is still a long way to go before we can make any claims to have developed a sustainable global growth model, but carbon offsetting is a step in the right direction".

Are Carbon Levels Really The Reason For Global Warming?

This is a passionately argued debate by governments, environmentalists and the general public. The likelihood of a clear unilateral agreement is slim. What is largely agreed is that carbon dioxide along with water vapour, methane, nitrous oxide, and ozone are recognised as the main greenhouse gases. What is also clear is that mankind is producing more and more of these gases, yet we are dependent on a global environment to survive and prosper.

With this in mind, our governments and we, as individuals, are in a position where we can proactively work towards a sustainable future.

Last Updated: September 2010