Geoengineering is the deliberate and large-scale intervention in the Earth’s climate system, usually in an attempt to mitigate global warming. It has been proposed as a way to reflect sunlight and cool the planet, remove greenhouse gases from the atmosphere, or stimulate ocean carbon uptake. Geoengineering is a highly controversial topic, with proponents arguing that it may be necessary to combat climate change, and opponents contending that it could have catastrophic unintended consequences.
Solar radiation management (SRM) geoengineering strategies aim to reflect a small portion of incoming solar radiation back into space, thereby cooling the planet. SRM techniques include injecting sulfate aerosols into the stratosphere, brightening clouds, and installing mirrors in space. Carbon dioxide removal (CDR) geoengineering approaches seek to physically remove carbon dioxide from the atmosphere through methods such as direct air capture or enhanced weathering of rocks. Stimulating ocean carbon uptake is another possible geoengineering strategy; this could be accomplished by fertilizing the ocean with iron or other nutrients to encourage the growth of photosynthetic organisms that would take up carbon dioxide.
Geoengineering is a highly complex and uncertain endeavor; there is significant risk associated with large-scale manipulation of the Earth’s climate system. Proponents of geoengineering argue that it may be necessary to combat dangerous levels of anthropogenic climate change; however, critics contend that geoengineering could have disastrous unintended consequences, potentially exacerbating existing inequalities and resulting in new forms of environmental injustice. As such, any decision to implement geoengineering should be made carefully and only after thoughtful consideration of all risks and potential impacts.