Climate Engineering

Climate scientists are studying approaches that might alter the Earth’s climate in ways that would reduce the expected future warming due to increased abundances of greenhouse gases. Geoengineering initiatives focus on slowing climate change until CO2 emissions can be reduced, or on intervention in case climate “tipping points” such as massive glacial melting might be reached.

Potential methods to slow climate change vary; some remove or reduce greenhouse gases (GHGs) from the atmosphere, while others aim to increase the Earth's albedo (reflectivity) to reduce the amount of sunlight that warms the Earth. Increasing albedo can be accomplished by increasing the amount or character of clouds or by enhancing the reflective stratospheric aerosol layer.

At Atmospheric and Environmental Research (AER) scientists are doing fundamental research into the atmospheric effects of climate engineering. Working with colleagues at ETH, University of Calgary, and Dalhousie University, we’re investigating the impact of potential deliberate injection of aerosols into the atmosphere aimed at increasing the Earth’s albedo. The results from this computer modeling study have indicated that the Consequences of geoengineering by stratospheric aerosol injection would include changes in atmospheric circulation and precipitation patterns, changes in the vertical temperature structure of the atmosphere, and reductions in the stratospheric ozone layer.

Societal Knowledge

Human-induced climate change due to increasing GHG concentrations is a major societal concern discussed in the press, by politicians and by ordinary citizens every day. AER does not advocate climate engineering as a solution to global warming, but believes that solid science should inform governmental decisions on climate policy. Scientists at AER contribute to societal knowledge by:

  • Providing an objective assessment of the potential negative and positive consequences
  • Fostering international collaboration
  • Advancing state-of-the-science in the field of climate modeling

The AER modeling team has provided key contributions to this field for several decades including modeling of chemical transport and stratospheric aerosol microphysics. Examples include:

  • Studies of ozone depletion due to chlorofluorocarbons in the 1970s and 1980s
  • Contributions to WMO ozone assessment reports in 1979-2007
  • Studies of the impact of a fleet of stratospheric aircraft on ozone in 1991-1999
  • Contributions to the IPCC report “Aviation and the Global Atmosphere” in 1999 resulting in acknowledgement as an IPCC contributor to the 2007 Nobel Peace Prize
  • Lead author role in the SPARC report “Assessment of Stratospheric Aerosol Properties” published in 2006