Air traffic to become major source of global warming
As air traffic emissions double -- or even triple -- by 2050, a recent study in the journal Environmental Science & Technology indicates that air travel will become one of the significant factors in global warming. (Currently, global air traffic contributes 2 to 3 percent of carbon dioxide emissions, according to the report.)
The study's lead author, Bethan Owen of the Dalton Research Institute at Manchester Metropolitan University in the United Kingdom, answered my questions last week.
Why are air traffic emissions expected to increase so much?
Aviation emissions are largely driven by demand. Global aviation demand, in turn, tends to be driven by global economic growth. Many parts of the developing world currently experience a very low amount of air travel per capita and the potential for growth could thus very large on a global scale. The methods used for predicting future aviation demand in this paper are fairly conservative. The scenarios are based on the [Intergovernmental Panel on Climate Change Special Report on Emissions Scenarios] GDP growth predictions and the scenario story lines. Improvements in technology leading to better fuel efficiency are included in the scenarios to varying degrees. However, the rate of improvement in fuel efficiency does not generally keep pace with the growth in aviation in any of the scenarios in the first half of this century.
What kind of damage could these increasing emissions do?
CO2 emissions from aviation are no different from any other emission source. However, the non-CO2 climate effects from aviation also need to be considered. There is not a simple way of including all the effects of aviation using one metric as the different effects have varying time scales. Currently, international aviation emissions -- around half of the total -- are not part of the Kyoto Protocol or any other international emission reduction agreement. Future growth in aviation emissions against a background of reducing emissions in other sectors is potentially a significant issue.
What can we do about this problem?
The International Civil Aviation Organization is a specialized UN agency and acts as a global forum for aviation. The ICAO Committee for Aviation and Environmental Protection are currently developing ideas for a CO2 standard for aviation which may help force the pace of technological development.
Mitigation options for aviation include:
- Increased rate of technological development and uptake for fuel efficiency measures
- Alternative fuels, although there are major problems associated with this not least, the sustainable production of biomass feedstock
- Lower levels of future aviation activity than forecast
Image: Airplane / iStock
This post was originally published on Smartplanet.com