Wednesday, 24 December 2008

Carbon Clear's View on Radiative Forcing

At Carbon Clear we pride ourselves on work that is backed by sound science and ethics. This is true for everything we do, including our carbon calculations. Effective immediately, we have changed the way we account for the carbon footprint of airplane flights.

There has been a great deal of controversy about the global warming impact of high altitude airplane flights. Most scientists recognise that emissions from burning jet fuel at altitude leads to a greater warming effect than if that fuel were consumed at ground level, but the exact amount o that impact depends on a number of complicated assumptions. This has led to different carbon calculators using multiplication factors ranging from 1.0 to 4.0 to account for this increased warming. Defra, the UK's main environment agency, uses a factor of 1.0 on its online carbon calculator, and the European Environment Agency looks set to follow suit.

Until recently, Carbon Clear has followed Defra's example with an emissions factor of 1.0 - a litre of fuel was assumed to have the same warming impact wherever it is consumed. However, after consulting a range of expert stakeholders, we now base our aircraft emissions factors on work commissioned by the Intergovernmental Panel on Climate Change, or IPCC entitled "Aviation and the Global Atmosphere". The IPCC's work represents the consensus opinion of climate scientists from around the world.

While the IPCC report notes that it is prudent to provide a range rather than a single number, the most likely estimates centre around a Radiative Forcing Impact (RFI) from high altitude flights that is approximately 2.7 times the global warming impact of ground transport. This means that we need nearly three times as much carbon reducing activity to compensate for the effects of customer flights. We will monitor the RFI debate and encourage a policy and scientific consensus so that we can continue to provide the best possible advice to our customers.

Every individual and company has a role to play in tackling climate change. At Carbon Clear we're committed to helping you control your carbon impact.

(Carbon Clear website)