- It is one of the principal contributors to global environmental problems such as climate change, ozone depletion, and the wasteful use of scarce raw materials;
- It encourages unnecessary travel. The tourist industry encourages people are able to travel to 'exotic' locations, which must exist on an unreliable tourist income. When the area has become overdeveloped, the tourists leave, to colonise the latest 'fashionable' resort.
The construction of the second runway would lead to:
- A largely unsustainable form of transport further encouraged;
- Higher emissions of global warming gases and other pollutants;
- Ozone layer destruction (in particular, from a new generation of supersonic airliners).
The problem is as as much to with where the aircraft fly,as how much they emit. For example, nitrogen oxide emmissions (NOx) from aircraft account for around 3% of anthropogenic NOx emissions, yet 25-30% of total NOx in the upper troposhere could be due toaircraft emissions (note 1) (the troposhere extends to the tropopause at around 15km, and above this lies the stratosphere).1. Promotion of an unsustainable form of transport.
Aircraft are major sources of greenhouse gases particularly carbon dioxide (CO2), water vapour, and nitrogen oxides (NOx). We need to reduce our total carbon dioxide emissions by 60% to merely stabilise atmospheric CO2 at current levels - considering that we in the developed world already emit more than our fair share, this means that the UK has to reduce CO2 emissions by 90%.
Water vapour at high altitudes causes dual problems. Firstly it leads to an increase in cirrus cloud formation, which contributes to global warming, and secondly it reacts with NOx to destroy ozone in the stratosphere.
Nitrogen oxide in the troposhere (i.e. below the ozone layer), has a totally different effect to in the stratosphere due to the complexnature of atmospheric processes. Here it contributes to ozone formation. Unfortunately this does not help replenish the ozone layer as it is in the wrong place, but instead acts as a greenhouse gas as well as contributing to smog around airports.3. Ozone layer destruction.
Recent research has also focussed on the role of sulphur emissions (in the form of SO2 and SO3) leading to H2SO4 aerosol formation (note 2), and this may well prove as important in ozone layer depletion as the role of NOx.
It is becoming increasingly clear that the effects of aircraft on complex atmospheric processes are one of the major threats to our environment.References: