A revised estimate of aviation’s impact on the environment is misleading and is based on ‘considerable uncertainty’ of some of the gases used in the measurement process, according to The International Air Cargo Association (TIACA).

The authors of the ‘Aviation and Global Climate Change in the 21st Century’ paper had previously assessed aviation’s contribution to climate change to be 3%‘in the Fourth Assessment Reports (AR4). However, in their latest report they have increased the figure for aviation’s contribution to climate change to 3.5% without cirrus and 4.9% with cirrus.

TIACA is challenging the increase which includes updated values of kerosene fuel sales based on International Energy Agency reported data.‘This latest report used the data to revise aviation’s radiative forcing (RF) to reflect an increase in traffic, fuel use, and total aviation RF over the period 2000-2005, including estimates of cirrus cloud formation.

The Association still believes a more accurate assessment was reported in 1999 by The Intergovernmental Panel on Climate Change’(IPCC). In its report on aviation and climate change, it estimated that aircraft emitted 2% of man-made CO2 ’ a figure it forecast would grow to 3% in 2050.‘The new report continues to confirm CO2 data that indicates aviation remains 2% of anthropogenic CO2 but the figure is then increased with the added impact of what TIACA calls ‘uncertain gases.’

Daniel Fernandez, TIACA’s Secretary General, said: ‘Aviation is the only industry that has asked the IPCC for a total assessment on climate change. The original assessment done in 1999 used RF as a way to assess the impact beyond CO2.‘Given the considerable uncertainty of the other gases, particularly those like’aviation-induced cloudiness’(AIC)‘that is unique to aviation, a more direct and understood comparison of aviation to other anthropogenic actives is better done via CO2.

‘The air cargo industry takes its environmental responsibilities extremely seriously and has made significant advancements in reducing its carbon footprint. While we believe it is too early to count the impact of gases whose effect in not yet fully understood, TIACA will continue to monitor the effects’other gases ’ such as NOx, H2O vapour, contrails, AIC, sulphate particles, and soot particles - have on’climate change and’as more is understood about what these effects are, we will be in a better position to correctly address how aviation can reduce its’impact on the environment.’