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Emissions down .. forecasts up .. targets level .. ! ?

12th February, 2009

The latest government figures for aviation emissions suggest a decline. But forecasts show a massive increase while Goeff Hoon has agreed a stabilisation target.

Figures published by DEFRA last week suggested that carbon dioxide (CO2) emissions from aviation declined between 2006 and 2007.  There was apparently a drop of 2.2%.  This is despite the fact that passenger traffic rose by 2.3%.

A drop in emissions seems unlikely. In most years since 1990 emissions have gone up due to increases in passenger traffic and there is no obvious reason for a reversal of the trend.

Over the years there has been a gradual improvement in fuel efficiency of aircraft. But progress is slow – the improvement is reckoned to be only about 1% per annum or a little over. A similar rate of increase is forecast over the next couple of decades. Improvement in fuel efficiency is therefore unlikely to be the explanation.        

The most likely explanation of the drop in 2007 is simply that the estimates are inaccurate. DEFRA uses ‘bunker fuels’, ie fuel loaded into aircraft in the UK, as the basis of the CO2 emissions. This is acknowledged to be an imperfect measure, mainly because aircraft have a choice (sometimes) as to where to load fuel, UK or abroad. With the volatility in the oil market and wildly fluctuating prices, it is possible that airlines chose to load up more often abroad in 2007.

For these reasons, AEF would need to see some good evidence before accepting there has been a drop in CO2 emissions.


While emissions were reported by DEFRA as declining from 2006 to 2007, DfT forecasts large increases up to 2050. Their new forecasts show a rise of 60% between 2005 and 2050.


But on the same day as DfT published these forecasts, transport secretary Geoff Hoon was speaking in the Heathrow debate and agreed a target of NO increase between 2005 and 2050.


We admit to being puzzled and confused.

There are few, if any, more important aviation statistics than CO2 emissions. We shall therefore be investigating further.