This story is part of Covering Climate Now, a global collaboration of more than 250 news outlets to strengthen coverage of the climate story.
In 2019, I think it's safe to say that humans are capable of wreaking great and terrible changes upon Earth's systems. To name a few: acid rain, deforestation, and climate change. Reversing such problems is, on its face, quite simple. Stop releasing smog-forming pollution. Stop cutting down forests. Stop burning fossil fuels.
In some cases, humanity has risen to these challenges, and for example, greatly reduced acid rain in North America since the 1970s, 80s, and 90s. But when it comes to climate change, there's a growing chorus, often bolstered by the fossil fuel industry, who support a controversial set of approaches to mitigating global warming, not by directly addressing the primary source of the problem — continuing to combust great volumes of oil, gas, and coal — but by further inducing massive changes to planetary systems.
I'm talking about geoengineering, and specifically solar geoengineering, which seeks to lessen global warming's greenhouse effect by reflecting sunlight, and heat, back out to space.