Both Bong Joon-ho's 2013 cli-fi film, Snowpiercer, and the ongoing TNT television adaptation of the same name offer audiences a bleak view of humanity's future. In a desperate attempt to combat rising global temperatures, 79 countries deploy the chemical CW7 into the upper atmosphere. The project works, only too well. Temperatures decline and keep on plummeting, plunging the planet into an ice age. Most of the life on Earth dies, save for a small remnant of humanity living aboard a globe-spanning train.
In Snowpiercer, climate engineering leads to catastrophic results. In the real world, our best bet at slowing or stopping climate change is to drastically reduce emissions. But climate engineering does offer some alternative (though less-understood) solutions.
The effects of pollution on climate are more complex than we previously supposed. Contrary to popular belief, not everything we dump into the air contributes to warming. In fact, some pollution has a cooling effect. This is not to say more pollution is the answer, but scientists are exploring how we might use this relationship to reduce warming.
Some small atmospheric particles reflect sunlight back into space before it reaches the surface. In nature, we encounter this phenomenon a few ways. Clouds reflect about 25 percent of solar radiation back into space.
More dramatically, volcanic eruptions cool global temperatures by dumping sulfates into the upper atmosphere. In 1991, Mount Pinatubo ejected 20 million tons of the stuff into the air. As a result, average global temperatures dropped about half a degree for the next two years, until the sulfates finally made their way back to the ground. In 1815, Tambora erupted in Indonesia, causing global temperatures to fall so dramatically that 1816 became known as "the year without a summer."
The idea behind solar climate engineering is to take this process out of nature and bring it under our control. Releasing particles into the atmosphere would artificially replicate the effects we see after some large volcanic eruptions. Environmentalists stress, however, that this would not be an end solution to climate change. At best, it's a Band-Aid. At worst, it could distract from more crucial efforts to reduce, eliminate, and remove emissions.
While cooling the planet in this way would treat some of the warming symptoms of climate change, it would do nothing to change the levels of carbon in the atmosphere. It also wouldn't do anything to curb ocean acidification.
Moreover, it could change precipitation patterns in ways we don't fully understand, driving rainfall to some parts of the world while creating or exacerbating drought conditions in others. Economic estimates indicate a global dimming initiative would be relatively low cost. Somewhere in the $1 billion to $10 billion per year range to achieve 1.5 degrees Celsius of cooling. Of course, we need more data before a global project could proceed.
SCoPEx, short for Strategic Controlled Perturbation Experiment, out of Harvard University, hopes to be an early player in gathering that data. As of December 2020, they were preparing for a test flight of an experimental balloon craft capable of delivering particulates into the stratosphere. Approval of the flight could come as early as next month. If that happens, the test flight could happen this summer.
According to the most recent measurements, global atmospheric carbon is at 415 parts per million. So far as we can tell, that's higher than it has ever been. Even if we went entirely carbon-neutral today, we're already more than 30 percent higher than the highest pre-industrial peak of about 300 ppm.
Slowing or halting the progression is vitally important if we hope to avoid the most catastrophic effects of climate change, but stopping now may not be enough. We need to reverse course. In short, we've run our planetary oven too hot for too long, and now we need to find a way to un-cook the proverbial goose. One way we might do that is through carbon capture technology.
Carbon capture isn't exactly new, but it has received renewed attention as of late. Elon Musk, for instance, just pledged $100 million toward a prize for the best new CC technology. It's already in use at some power plants, capturing carbon from exhaust feeds. Coal plants, for instance, can capture up to 90 percent of exhaust carbon for use in other products. In fact, the CO2 used to carbonate soft drinks comes from this process.
Capturing carbon at the power plant exhaust point is relatively easy to do: The carbon exists in high concentrations, but it does little to actually reduce emissions. Burning fossil fuels takes sequestered carbon from the geosphere and releases it into the biosphere. Any effective climate engineering must do the opposite: remove carbon from the air and sequester it again. The best technology would be able to do this not only from power plant exhaust points but from the atmosphere itself.
Engineers at MIT may have found a way to do just that. The device they've created is a battery system coated with polyanthraquinone, a compound that has an affinity for carbon. It works by passing air through the system as the electrodes charge, binding carbon to the electrode surface. Discharging the batteries releases the carbon.
This system operates at room temperature and is capable of capturing carbon at low concentrations, down to the levels we find in our atmosphere. This technology is scalable and works anywhere and everywhere. Once set up, it pulls carbon from the air, in what's known as Direct Air Capture (DAC). This sort of technology is what's needed to achieve negative emissions and actually lower the level of atmospheric carbon.
The question then becomes what to do with it once we've caught it. Today, companies use captured carbon for secondary products (soft drink carbonation or designer fuels, for example). While upcycling carbon prevents burning additional fuels, it's still ultimately released into the atmosphere. There's just an extra step along the way. Aggressive climate engineering requires Carbon Capture and Sequestration (CCS).
There are a few ways to do this. The one that probably comes to mind is biological sequestration, the storage of carbon in vegetation. Changing the way we manage forests and farmlands has the potential to reduce atmospheric concentrations, trapping carbon in the soil.
We could also store carbon underground, injecting it into porous rock, returning it to the geosphere from whence it came. Lastly, there are technological solutions, like using carbon to produce graphene. No matter the method, the goal is the same: Remove carbon from the air and store it someplace else.
While we don't yet have a clear understanding of the consequences of climate engineering, it's unlikely any of the proposed technologies would result in something so dramatic as Snowpiercer's frozen Earth. In truth, the opposite is more likely.
Direct Air Capture and particulate deployment may kick the can down the road but won't be enough on their own. Most experts agree climate engineering — if it's used at all — should only be one part of a larger plan to address climate change. The primary focus must remain on reducing our emissions and transitioning to renewable, carbon-free energy sources.
If the populace and policymakers believe we can mitigate or eliminate the risks of climate change by technologically tinkering with the environment, it could remove the motive to actually solve the problem. Why treat the disease when you can mask the symptoms?
Climate engineering's largest threat is not overextension, it's apathy.