Aviation accounts for 2% of the world’s carbon dioxide emissions
The UN Intergovernmental Panel on Climate Change (IPCC) states that aviation today accounts for about 2 per cent of global fossil carbon dioxide emissions. Together with emissions of nitrogen oxides, steam and effects of condensation trails, it is estimated that aviation is responsible for about 3.5 per cent of humankind’s total impact on climate change.
Aviation accounts for 4-5 per cent of Sweden’s total fossil carbon dioxide emissions. The transport sector in turn is responsible for about a third of Sweden’s total fossil carbon dioxide emissions. This is a larger percentage than for the world as a whole and is because Sweden has an otherwise cleaner supply of energy, thanks in part to hydroelectricity.
Aircraft, like other vehicles powered by fossil fuel, release carbon dioxide in direct relation to their fuel consumption. Moreover, at high altitude, aircraft also have an environmental impact through their emission of nitrogen oxides, steam and condensation trails. There is still great scientific uncertainty about the environmental impact of these emissions.
A jet engine releases the same substances as for all combustion of fossil fuel: carbon dioxide, nitrogen oxides, hydrocarbons, soot, other particulate matter, carbon monoxide and sulfur dioxide.
There may sometimes be a strong smell of jet fuel at airports. What makes jet fuel smell is sulfur impurities, known as mercaptans, which have a penetrating, intense and characteristic odour in very small concentrations.
Sulfur impurities belong to a group of substances that cause odour problems in conjunction with the production of pulp (the sulfate process). Mercaptans are non-toxic in the low concentrations found at Swedavia’s airports.
Aircraft whirlwinds are not fuel dumping
All aircraft leave whirlwinds in their wake. When it is humid out, the whirlwinds are visible because condensation is formed from the steam in the air. It may sometimes look as if the aircraft is dumping fuel while landing. The whirlwind in the wake of an aircraft is called a vortex.
Fuel dumping occurs very rarely and only in emergency situations when a plane needs to make an emergency landing. Only the largest aircraft are able to dump fuel. If dumping is necessary, it must be done over water and at such an altitude that the fuel vaporises before it reaches the ground.
Improving environmental performance of aircraft
European aviation research and the aviation sector expect that by 2020 it will be possible to develop aircraft with 50 per cent less fuel consumption and thus carbon dioxide emissions, 80 per cent lower emissions of nitrogen oxides and 50 per cent less noise, compared to an aircraft produced today. Compared with aircraft from the 1960s, today’s aircraft are 70 per cent more fuel-efficient per person/kilometre. The most modern aircraft use about 3.0 litres of fuel for 100 kilometres per passenger.
Rapid progress is being made in developing alternative fuels for commercial aviation. The fuels with the greatest potential are second generation biofuels, which consist of ingredients such as algae, jatropha and camelina. These fuels can be mixed with fossil fuels (up to a maximum of 50% for commercial flights) and are expected to constitute a significant percentage of the blend as early as 2020.
Swedavia is taking part in a Nordic project together with Nordic airlines, airports, government authorities and aircraft manufacturers to find the most effective supply of renewable fuel for the aviation sector. This partnership has a very clearly formulated objective. Three pilot facilities are working to produce renewable jet fuel before 2016 in Sweden, Norway, Denmark and Finland. The conditions for implementing a new fuel are favourable. Renewable fuel can be used, and is already being used to some extent, in existing jet engines, and the infrastructure at airports is also flexible. There is also a cross-industry Nordic collaboration to bring together organisations involved throughout supply chain. As a result, it involves, agriculture and forestry, technology companies, producers and decision-makers.
The concept of green flights consists of three aspects – green departure, direct route and green approach. Separately and together, they contribute to greener flights – which benefit both airlines and passengers. Green flights are carried out in collaboration between Swedavia, air traffic management (LFV) and the airlines.
Green flights – read more
The issue of climate change is of strategic importance to the entire aviation sector. The aviation sector is therefore the first global sector to agree long-term global environmental objectives.
The aviation sector’s objectives entail that:
- fossil carbon dioxide emissions from aviation shall be reduced by 1.5 per cent per passenger/kilometre by 2020. After that, emissions will not be allowed to increase even if traffic increases.
- by 2050 actual fossil carbon dioxide emissions shall be half the 2005 level.
Air traffic growth globally and in Sweden
Internationally, air travel is expected to increase by about 4 per cent annually through the mid-2020s. The largest increases are predicted in Asia and the Pacific, between Asia and Europe, and in China and India. Europe and North America are relatively mature markets with lower growth rates. The growth rate for Sweden is expected to be about 2 per cent annually. The number of international passengers will rise more, while domestic air travel is instead expected to fall somewhat in the coming years.