Every day, humankind pumps greenhouse gases into the atmosphere, which slowly warm the planet and threaten our future. What if we could fight global warming the same way? That's what some scientists are trying to figure out. The concept is called geoengineering, and while it could pose risks we haven't even begun to fathom, it could also be the solution to our climate troubles.
The Grand Plans
Geoengineering is an umbrella term for a lot of ideas that have been kicked around. According to the University of Oxford, it's defined as a deliberate, large-scale intervention in the Earth's natural systems to counteract climate change. How that plays out, though, is fair game. The proposed techniques generally fall into one of two categories.
The first category involves removing carbon dioxide from the atmosphere. A lot of the plans in this realm deal with the ocean: we could fertilize it with iron to grow more plankton, which would take carbon out of the atmosphere and to the bottom of the sea when they die; or we could dissolve alkaline rocks in it to reduce ocean acidification and increase its ability to store carbon. We could build machines to "scrub" carbon from the air the way they do in factories, or we could even just plant more trees — if we had the land for it, anyway.
The second category involves managing the sun's energy so that it can't contribute to rising temperatures. That might involve reflecting sunlight back into space through something like stratospheric injection, where high-altitude balloons would spray a mist of fine particles or sulfuric gasses into the stratosphere where they could reflect and direct the sun's heat away from our planet. Or it could mean thinning out some of the thick cirrus clouds that trap Earth's heat like a blanket. Cloud seeding, as it's called, would use drones to sprinkle fine particles in the upper troposphere to make the clouds produce larger ice crystals and, therefore, thinner clouds.
Of course, these plans are hardly met with open arms. Suggest filling the atmosphere or the ocean with vast quantities of sulfur or iron or limestone, and you're bound to set off some alarm bells. Playing God with our planet's atmosphere could have some severe unintended consequences, and it's hard to know how likely those could be.
For an example, think about how we've tinkered with species populations. Killing off a threat like the wolves in Yellowstone has historically made the populations of other species explode, which decimates their food supply and makes it worse for every other animal in the environment. If we purposely pollute the air or water, we might fix climate change, but what side effects might result?
But if climate change gets any worse, the side effects might be a small price to pay. As Stanford atmospheric scientist Ken Caldeira tells Inverse, "...what seems like a bad idea today could seem like the best available option somewhere down the road."