Carbon offsetting

There are two types of carbon offset. Here we consider only the voluntary market, as opposed to the compliance market, which refers only to companies and governments and other large entities who use carbon offers to comply with caps and agreed limitations. The smaller voluntary market enables individuals, companies and governments to compensate for their emissions and contribute to balancing out their carbon footprint.

Offsets are measured in tonnes of carbon dioxide equivalent; therefore 1 carbon offset is the equivalent to reducing the emissions of carbon dioxide, or its equivalent of other greenhouse gases, by 1 tonne. In the UK, the average carbon footprint (i.e. per person) is around 15 tonnes per year. According to UK Government sources, a car emits around 171g of CO2 equivalent per kilometre per passenger; in other words, a journey of around 5,800km would emit 1 tonne of carbon dioxide equivalent. As you might imagine, making such estimates is not easy because there are many different factors to consider – what sort of fuel does the car use, how economic is it with fuel, what speeds does it travel at and for how long, and so on.

There are many different types of carbon offset schemes and they support different types of projects. Some examples include:

  • Climate Care, which supports safe drinking water & fuel efficiency in Africa and rainforests in Brazil;
  • Flygreen invests in solar panels in India;
  • Gold Standard supports water purification in Asia and fuel efficiency in Africa;
  • Myclimate is reforesting in Central America and supporting fuel efficiency in Africa.

These sites typically request the details of your carbon-emitting activity to quantify it and then quote the amount required to offset it. Flygreen provides flight offers and if you book through them will cover the cost of the carbon offset. Many companies use carbon offset schemes to reduce their impact and/ or to improve their green credentials. Typical examples include airlines, oil & gas companies and manufacturers. Another option is to donate to conservation organizations such as the Woodland Trust. Tree planting is a popular way of offsetting; according to, a ten-year-old tree absorbs 22kg of CO2 per year; in other words, 45 ten-year-old trees absorb a tonne of CO2 in a year.

While there are clear benefits of carbon offsets, there are also a few issues, perhaps foremost that it should not discourage the avoidance of carbon emissions: better to avoid taking a flight in the first place than offsetting it. Secondly, as mentioned above, it is not straightforward to calculate the emissions of different activities as this depends on many factors. While both Climatecare and Myclimate both agree on the distance between Heathrow and Paris Orly airports, one estimates it incurs 0.11 tonnes, costing £0.86 to offset, while another estimates 0.26 tonnes and charging £6.00 to offset. Furthermore, such sites need to be regulated not only to ensure they are providing such estimates accurately and consistently, but also that they are following through with their obligations.