Geoengineering represents several technological or large-scale approaches for offsetting the effects of climate change. Rather than conventional mitigation approaches that result in lower greenhouse gas emissions (such as switching to electric vehicles or investing in renewable energy), geoengineering approaches represent far more technical or radical interventions intended to stop climate change.
Broadly speaking there are two basic approaches:
- Greenhouse Gas Removal – removing greenhouse gases (but especially carbon dioxide) from the atmosphere. Methods for doing this include capturing gases as they are released, use giant air scrubbers to directly capture greenhouse gases from the air, or planting huge numbers of trees. The end result is less greenhouse gases in the sky, and lower average temperatures.
- Solar Radiation Management: making the Earth more reflective so that light from the sun bounces back into space. You can use artificial snow or reflective materials to protect ice sheets, paint roofs and buildings reflective colors, add reflective aerosols to the upper atmosphere, or even use reflective objects in space to reflect light away from the Earth. The end result is less solar radiation being absorbed by the Earth, and lower average temperatures.
You can probably guess that pretty much every geoengineering approach (with the exception of afforestation, planting huge numbers of trees) is controversial, with many detractors. Criticisms include geoengineering approaches being poorly studied, some approaches are currently expensive, some proposals have unknown negative side effects, some of these approaches have massive consequences for international relations, and pursuing geoengineering instead of climate mitigation could give polluting nations and companies an excuse to keep polluting.
Geoengineering isn’t a panacea – but, like I’m going to be saying for the rest of my life, climate change is dire enough that any and all solutions need to be on the table.
There are over a dozen geoengineering approaches already proposed, from relatively conventional like afforestation, to the truly sci-fi idea of adding orbital mirrors to reflect sunlight. But, whether conventional or radical, I’m going to be evaluating each approach for its effectiveness at stopping climate change and how easily it could be used at large scales.