Climate engineering

Climate engineering (or geoengineering) is an umbrella term for both carbon dioxide removal and solar radiation modification, when applied at a planetary scale.^[1]: 168 However, these two processes have very different characteristics. For this reason, the Intergovernmental Panel on Climate Change no longer uses this overarching term.^{[1]: 168 [2]} Carbon dioxide removal approaches are part of climate change mitigation. Solar radiation modification is reflecting some sunlight (solar radiation) back to space.^[3] Some publications place passive radiative cooling into the climate engineering category. This technology increases the Earth's thermal emittance.^[4][5][6] The media tends to use climate engineering also for other technologies such as glacier stabilization, ocean liming, and iron fertilization of oceans. The latter would modify carbon sequestration processes that take place in oceans.

Some types of climate engineering are highly controversial due to the large uncertainties around effectiveness, side effects and unforeseen consequences.^[7] Interventions at large scale run a greater risk of unintended disruptions of natural systems, resulting in a dilemma that such disruptions might be more damaging than the climate damage that they offset.^[8] However, the risks of such interventions must be seen in the context of the trajectory of climate change without them.^[8][9]

The Union of Concerned Scientists points to the danger that the use of climate engineering technology will become an excuse not to address the root causes of climate change, slow our emissions reductions and start moving toward a low-carbon economy.^[10]