Climate Change

Like other users of fossil fuels, aircraft emit CO2, NOx, soot, water, and sulfates into the atmosphere, all of which can impact the earth’s energy balance. Moreover, because of the altitude at which the emissions are deposited, the effects on the climate can be accentuated, especially through the formation of contrails and high altitude cirrus clouds. Aviation emissions currently account for between 2%-5% of direct anthropogenic radiative forcing (energy imbalance), and this percentage is expected to increase over the next 30 years.

It is critical that aviation’s climatic effects are modeled appropriately so their environmental costs, as well as the societal costs of adaptation and mitigation, can be understood. Different emissions species have different magnitudes of impact and act across different lifetimes, making it critical to develop appropriate models of the Earth’s climate system.

The Laboratory for Aviation and the Environment (LAE) assesses the economic impacts of aviation-related climate change. We developed an approach that estimates the relationship between changes in aviation emission projections and changes in the Earth’s energy balance, average temperature, and total societal damages. Our climate model is part of the Aviation environmental Portfolio Management Tool (APMT) and has been used extensively to inform policy deliberations in domestic and international contexts.

The lab also undertakes fundamental studies into the mechanisms of aviation-related impacts on the atmosphere and climate. Examples include studies of the impact of aircraft emissions on stratospheric chemistry, cross-coupling between aircraft and other emissions in terms of their climate impacts, and coupling between air quality and climate change.

We are also researching the implications of proposed geoengineering schemes. We are investigating the potential efficacy and impacts of deploying an “aerosol shield” in the stratosphere to reflect incoming solar radiation and thereby offset a portion of warming. The aim of this research is to foster a balanced understanding of the risks and potential benefits of geoengineering, so that should such a measure ever be required knowledge about it’s environmental implications will be in-hand.