Tuesday, May 29, 2007

heathrow: the uk's worst emitter

More aviation emission maths!

Last week the Camp for Climate Action announced the target for this August's camp. Ambitously, it's Heathrow Airport.

In their press release, they say Heathrow is the UK's largest emitting site. A hell of a claim, given last year's target was Drax power station in Yorkshire, which emits more than most countries.

The press release explains their calculations:


No official government or BAA figures are available.

The conservative calculation is:
Heathrow uses 20 million litres of fuel per day
(International Air Transport Association).

Each litre of fuel produces 2.53 Kg CO2
(Jet fuel).

Thus 18.4 million tonnes CO2 per year are emitted.

That the total impact of aviation on climate is higher than the effect of its CO2 emission alone is scientifically uncontroversial. However, the amount of extra-warming from aircraft is: the Intergovernmental Panel on Climate Change use a factor of 2.7 (Aviation and The Global Atmosphere, 1999), the UK Government 2.0 (The Future of Transport, July 2004), and the full range of studies range from 1.7-4.0 (Predict and Decide, University of Oxford Climate Change Institute).

Thus using the lowest possible factor, 1.7 x 18.4 = 31.3 million tonnes CO2-equivalent per year, making Heathrow by far the largest UK emitter.


By comparison, Drax is reported to have emitted 20.8 tonnes in 2005.

Compare that with the countries on this list. (Note: the list gives emissions in tonnes of carbon. To get the equivalent in carbon dioxide, multiply by 3.667)

Out of 212 countries on earth, Drax would be 79th, Heathrow would be 71st. And that's the most conservative maths; there's a very real chance it's a lot worse.

So, see you at Heathrow in August.

= = = = = = = = = =

UPDATE 15 JAN 09

As is explained here, the multiplication factor has changed. This sin't so much to do with any change in science as in accounting. The standard way of measuring the climate impact of an activity is its impact over the next 100 years. Aviation hasn't been measured like this, but now it is being, and the multiplication factor is 1.3.

As such, the figure above for emissions should be multiplied by 1.3 x 18.4 = 23.92 million tonnes CO2-equivalent per year. A lower figure, but it still makes Heathrow the largest UK emitter and if it were a country it would rank 75th out of 212.

2 comments:

PMM said...

Hang on a minute...

The link giving the country by country list reckons that the UK produces 152.460 million metric tons of CO2 per year.

You say that Drax produced 20.8 and heathrow produced 31.3 at a conservative estimate.

That comes to 52.1 million tons just from those two sources.

Are you really saying that one power station and one airport combined produce a third of the entire carbon output of the UK?

Personally, I find this doesn't quite ring true. There are many power stations, and many airports. There are supermarkets heating their freezers with their lighing. There are a squillion cars vans lorries trains trams and motorbikes putting their share of filth and CO2 into the sky.

If the figures add up (and I'm sure they do, I just find them extremely surprising) then closing these two facilities would instantly reduce the UK's carbon footprint by a third.

merrick said...

Oh my dear PMM, back up a bit.

first up, you've chucked in a superfluous decimal point.

Then there's the difference between carbon and CO2 equivalent.

'Note: the list gives emissions in tonnes of carbon. To get the equivalent in carbon dioxide, multiply by 3.667'.

That gives the UK 41576.2 t/CO2 equivalent. So, by my rough and ready reckoning, that means Drax and Heathrow combined are around one eight-hundredth of our emissions.