Hey, have you heard the news? We’re all doomed!
At least according to the new UN climate report that says we have just twelve years to get our collective acts together and stop polluting or we will do irreparable damage to the Earth. Many read news like this and completely tune out, the scale of the problem too overwhelming to really affect them. Still other, perhaps more civically-minded people, freak out- deciding to be more conscientious in their recycling or to maybe even go vegan.
Unfortunately, the simple fact is fixing the problem of global climate change is no longer an individual undertaking: it requires global solutions. But what if we all pull together and mend the error in our ways—stop polluting, use renewable energy sources, and live carbon neutral lives—and it still isn’t enough? Well that’s where something called geoengineering comes in, and it may be our best chance at keeping the world alive… or it might just kill it.
What is geoengineering?
The National Academy of Sciences defines geoengineering as, “options that would involve large-scale engineering of our environment in order to combat or counteract the effects of changes in atmospheric chemistry.” Or, more simply put, it’s the idea of using science on a global scale to cool the Earth back down to a sustainable level.
Sounds simple enough right? But the problem is that engineering on that scale is a simply unfounded territory. The largest engineering project humans have ever undertaken is the Beijing Airport which will sprawl out over more than 25 square miles when it’s completed. But that is 7.8 MILLION times smaller than the scale of the average geoengineering project.
In addition to this monumental scalar impact, there is the fact that any project would have to work across a multitude of different ecosystems without poisoning or disrupting anything, and we simply have no way of knowing that for sure ahead of time. On top of all of this, if you ever expect world governments to get behind the idea, it’s also got to make them money somehow.
Are you beginning to see the issue?
The thing is though, despite all the pessimism, and the endless series of obstacles laid out in front of them, many scientists and engineers are still ready to tackle the problem of geoengineering, and more importantly, are devising methods that may just fit all of the criteria.
Solar Radiation Reduction VS. Carbon Capture and Removal
Geoengineering tactics generally fall into two broad categories: blocking new solar radiation or removing CO2 from the air. These are simply the most direct ways to combat the issue of global warming and will have the quickest impact in terms of halting the rise in global temperature and ice cap thaw.
Yet while this sounds great in theory, the truth is many of the current strategies run the risk of significant detrimental side effects. Fortunately, engineers and scientists across the world are designing new technologies, running simulations, and testing theories to make them better.
Let’s quickly go through six of the geoengineering techniques most promising as a way to manage Earth’s climate.
High-atmosphere sulfur aerosols:
This plan involves pumping SO2 into the stratosphere with a fleet of airplanes. Once there it will form aerosols with the surrounding molecules and reflect sunlight straight back into space, thus cooling the planet. A lot of people are excited about this approach because it could offset the warming we currently experience and more, is very feasible with current technology, and extremely cheap compared to most other approaches.
We already know this solution would work—Volcanoes do it all the time and we routinely see measurable global cooling after even relatively minor volcanic events. However, much like a volcano, there is a downside. First and foremost, it would reduce rainfall, which might sound great if you’re recovering from a hurricane right now, but could be disastrous for other areas of the world experiencing historic droughts because of climate change. Less sun could also unpredictably alter fragile environments, potentially hurting the most vulnerable.
And most annoyingly, without anything being done about carbon dioxide levels, you could never stop seeding the aerosols or the temperature would jump back up to where it was much quicker than before, so the “low cost” would eventually go to infinity.
The plan here is to retrofit a fleet of old ships to spray a seawater aerosol into the air as they travel. The salt particles this spreads should increase the concentration of droplets in the clouds making them whiter and more reflective, thus cooling the planet. Again, this is an exciting approach because it could easily offset our current warming and doesn’t involve pumping scary-sounding chemicals into the air.
It is theoretically feasible to cool the poles more than the tropics with this approach which would slow or stop the loss of ice while letting the lower latitudes slowly return to normal. Unfortunately, this approach still has the issue or reducing rainfall since less sun would be getting through, and some scientists worry it could alter regional climates like the Amazon in especially disastrous ways by effecting its water cycle. But most of all, the main problem is that the technology necessary to do this kind of thing at scale simply doesn’t exist, get on that science!
Space-based Solar Shield:
One of the more… shall we say “inventive” approaches is the idea of launching hundreds, or potentially millions, of orbiting “parasols” into deep space to shade the Earth. As for the pros: I mean, yeah, technically it would work. Cons: it would be unbelievably expensive without something like a space elevator—and a space elevator would also be too expensive!
Now we are into the carbon-reduction approaches to geoengineering. This one calls for countries to work together to grow vast swathes of fast-growing plants and then regularly turn them into charcoal that can be sequestered in the soil. This method is attractive because it’s extremely safe. You’re using the natural process of photosynthesis to slow climate change rather than actively change the climate.
Biochar is also cost-effective, as the energy created in the charcoal process could be sold for profit. Unfortunately, it’s also not as effective as we might need. Current estimates are that it could only ever offset about 10% of the warming due to CO2 doubling. Ultimately though, this could still be a good approach for poorer countries who could be incentivized to devote land to the process and rewarded for every ton of carbon sequestered.
The oceans take up over 70% of the Earth’s surface, makes sense that you might want to use them to help solve this problem. The idea with ocean fertilization is to boost the growth of plankton across the board by adding nutrients such as iron to ocean waters. When the bloom reaches critical mass, the plankton simply dies off and sink to the bottom of the ocean, along with all the carbon they just consumed, then the process is simply repeated.
This approach would effectively slow climate change, and ocean acidification, and at the right scale would sequester more than enough of our atmospheric carbon. But the scale is also the problem here. The ocean is just so big that there isn’t currently (pun intended) an effective way to distribute enough excess nutrients to offset more than about 5% of warming due to a doubling of CO2.
On top of this, the project could have unforeseeable effects on already fragile marine ecosystems, and massive plankton blooms could even cause or accelerate the rise of deoxygenated ocean “dead zones”.
Direct air carbon capture (AKA artificial trees):
And we saved the best for last: Direct air carbon capture involves machines essentially mimicking photosynthesis, drawing CO2 from the air and making carbon to then be stored for other uses or simply buried. New designs for these artificial trees can suck up 100 times more carbon dioxide than a normal tree, almost 1 ton per day! And since the technology is still in its infancy, there is a long way for it still to go, which certainly makes it exciting.
The main drawback when it came to the idea of artificial trees was the seemingly massive upfront cost, as well as the long-term cost of the energy required to fuel the chemical reactions rendering the carbon capture moot. But the exponential rise in availability and drop in the cost of wind and solar power have solved the latter problem.
And as for the former, as we begin to see the cost that doing nothing will have, both monetarily and human, carbon capture technologies suddenly pay for themselves.
What are we doing NOW?
We’ve been talking a lot of doom and gloom, but the truth is that the future of geoengineering is bright! Small-scale, controlled tests of all kinds of different approaches are being undertaken in field sites all around the world. And in universities, more and more engineers are focusing their research on climate science meaning that all of these technologies are going to get more and more efficient in the coming years. You can even get a degree in Geoengineering at Oxford now!
There are also many companies that have begun to spring up in the climate engineering space. An Icelandic group known as CarbFix developed a novel strategy called “enhanced weathering” where captured carbon is pumped into basalt formations, permanently fixing it there with no harmful byproducts. And a company called Climeworks just opened a Direct Air Carbon Capture plant in Switzerland last year that makes back it's cost by selling carbon as fertilizer.
Things like this are just a start on our way to actually making a difference, but they are promising first steps, and perhaps signal that the world is finally ready to do something about climate change.
How to make the future cooler?
So, what’s the answer? How do we get started? Ultimately it’s not that complicated, we just need to start. Doesn’t really matter where. We can all do our parts in little ways and in big ones. And we can make sure our leaders know that this is a priority, and we won’t accept their stall tactics and greed anymore.
Ultimately, all of these approaches assume that we also stop dumping carbon into the atmosphere, and since over 70% of all manmade atmospheric carbon comes from just 100 companies, what we really need to do first and foremost is hold these institutions accountable for their pollution and force them to stop or at least 100% offset their carbon footprints immediately.
Additionally, we need to remember that this isn’t going to be something that will have a single solution. It will take a concerted effort across many different sectors to get the job done. For instance, if we were to curtail the warming trend without reducing our carbon emissions we would still be causing the oceans to acidify which could threaten the entire marine food chain and eventually leave millions of people without sustainable sources of food. And if we stopped emitting carbon right now but didn’t manage to remove any, we’d still be committing to over 3 meters of sea level rise over the next few decades, permanently displacing countless people.
In the end, we can at least say that it seems prudent to use scientifically robust, transparent research to improve our understanding of how the Earth might respond to geoengineering as we move through these next 12 crucial years.
There are a lot of promising solutions that we must simply learn more about, there are even many approaches that we haven’t covered here too- like cloud seeding or the simple act of reforestation- and all of them have their pros and cons, but the fact is that as technology advances we WILL have an answer to geoengineering that WILL work.
The only question is whether or not we as a global society can come together and implement it in time.