What Is Geo-engineering?

Geo-Engineering is an emerging branch of environmental science which seeks to alleviate environmental problems not by altering the patterns of human behaviour which led to the problems in the first place, but by using technology to make sweeping alterations to the natural environment in the hope of producing some desirable effect.

The schemes of the would-be geo-engineers often sound like science fiction and, until recently, most of the proposals were dismissed as crackpot ideas supported only fringe figures. Now, however, given growing concern about the problem of global warming, and the difficulties encountered in getting the international community to do anything about it, some of the geo-engineering projects are being considered seriously for the first time.

The plans include :

- Building a giant shield in space to screen out some of the sun's rays, and so reducing the temperature on earth.

- Constructing giant reservoirs to hold some of the excess water expected to come from melting icebergs.

- Using cloud-making machines to block out the sun.

The modern concept of Geo engineering (or Climate Engineering) is usually taken to mean proposals to deliberately manipulate the Earth's climate to counteract the effects of global warming from greenhouse gas emissions. The National Academy of Sciences defined geoengineering as "options that would involve large-scale engineering of our environment in order to combat or counteract the effects of changes in atmospheric chemistry."  Geo engineering accompanies mitigation and adaptation to form a 3-stranded 'MAG' approach to tackling global warming, notably advocated by the Institution of Mechanical Engineers.

Some geoengineering techniques are based on carbon sequestration. These techniques seek to reduce greenhouse gases in the atmosphere directly. These include direct methods (e.g. Carbon dioxide air capture) and indirect methods (e.g. Ocean iron fertilization). These techniques can be regarded as mitigation of global warming. Alternatively, solar radiation management techniques (e.g. Stratospheric sulfur aerosols) do not reduce greenhouse gas concentrations, and can only address the warming effects of carbon dioxide and other gases; they cannot address problems such as ocean acidification, which are expected as a result of rising carbon dioxide levels. Examples of proposed geoengineering techniques include the production of stratospheric sulfur aerosols, which was suggested by Paul Crutzen, and cloud reflectivity enhancement. Most techniques have at least some side effects.