Hazardous geo-engineering

Large-scale modifications to the earth's atmosphere, oceans and lithosphere have been proposed as solutions to various environmental problems or constraints. Even where apparently feasible and reasonable, such measures involve uncertainties and potential side-effects which could threaten the stability of entire regions of the planet.

A proposal to offset the warming effect due to greenhouse gases is to inject tons of sulphuric acid into the stratosphere to reflect radiant energy; others would create massive wetland areas of micro-algae to absorb excess carbon dioxide, or inject it deep into the oceans. Reconstruction of an entire river system was proposed in Russia to divert waters inland for irrigation rather than allow them to flow to the Arctic Ocean.