1 Geoengineering – what is it?

1.1 Definitions of geoengineering

Geoengineering is normally described as the deliberate modification of earth's environment on a large scale ‘to suit human needs and promote habitability’. The US 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’.

Wikipedia has an excellent introduction to the subject, where it states: ‘geoengineering is usually taken to mean proposals to deliberately manipulate the earth's climate to counteract the effects of global warming from greenhouse gas emissions’. See the Wikipedia article and its links for geoengineering. (While well structured, this article by no means contains a complete list of the geoengineering options that have been proposed.)

It is worth pointing out that we have, in effect, been unintentionally geoengineering the earth's climate for the last 300+ years by changing:

• the concentration of greenhouse gases in the atmosphere

• the albedo (reflectivity) of millions of square kilometres

• the water-holding capacity of many landscapes, etc.

While this does not strictly qualify as geoengineering because it wasn't, in most cases, deliberate, the effect is much the same. Measures to reduce, for example, the high temperature of road surfaces by making them paler and more reflective could therefore be described as reverse geoengineering or un-geoengineering.

One of the most respected voices in this field is Professor Ken Caldeira, who also runs a Googlegroup on the subject where it is possible for anyone to join the group, participate or just follow the discussions.