Researchers look into geoengineering possibilities

Researchers around the world are investigating the possibilities of artificially modifying the climate. Operating under the Academy of Finland's FICCA research programme, the COOL research project on aerosol intervention technologies for cooling the climate has engaged in the closer examination of two geoengineering techniques, which have seemed promising in international studies. This puts Finnish researchers at the international forefront in terms of both techniques.

According to project leader Ari Laaksonen, geoengineering tests cannot be conducted in practice. However, climate models can be employed to study the emergency measures that might be taken if the Earth's temperature rises to dangerous levels. In comparison to weather modification experiments undertaken in some parts of the world to create phenomena such as artificial rainfall, geoengineering involves large-scale manipulation.

The marine cloud whitening technique involves the spraying of sea water into the air to brighten clouds. As water evaporates from seaspray, the remaining salt particles form cloud condensation nuclei. When the nuclei collide with greyish low marine clouds, the clouds become brighter, reflecting solar radiation more effectively.

"We've calculated the effects of this technique in four coastal areas close to the equator, which have the highest levels of solar radiation. Although the air mass does cool, it seems that regional precipitation patterns are altered as a side effect. Since this could be detrimental to areas dependent on monsoon rain, any experimentation requires careful consideration," says Laaksonen, a professor at the Finnish Meteorological Institute.

Another technique examined was the use of commercial passenger aircraft flying at high altitudes to inject sulphate aerosols, emitted by aviation fuel, into the stratosphere. This would mimic a volcanic eruption, during which sulphur compounds are released into the stratosphere. They reflect solar radiation and thereby have a clear cooling effect on the climate. No previous calculations are available on the viability of using commercial flights in this way.

"In terms of efficient geoengineering strategies, this technique proved unviable. It would work best close to the equator, but little air traffic operates there – commercial flight routes are operated further north. In addition, current commercial aircraft are unable to fly high enough in the stratosphere. We would need new planes with large amounts of sulphur added to their fuel," Laaksonen says.

The COOL project is also examining the societal and legal aspects of geoengineering, since climate engineering by humans is a new idea that evokes mixed reactions.

"Among other issues, we've studied how various perspectives on geoengineering have been documented in different countries and by international bodies. Our conclusion is that discussion of the issue has been cautious so far. Not a single party, including the EU, has taken a clear stand on the matter," says Professor Mikael Hildén of the Finnish Environment Institute, which is involved in the COOL project.

Photos: Harriet Öster,


Last changed 30/04/2014