Solar Geoengineering – The Climate Solution We Don’t Want to Use

Ahh, solar geoengineering – the climate solution that we don’t want to use. Or, as author Jeff Goodell calls it, the “nightmare fix for climate change.” I’m not going to explain everything just yet because it’s somewhat difficult to wrap your head around, but I’ll tell you this right now: this is a VERY interesting subject. I was very excited to research and write about it and, hopefully by the end of the article, you’ll feel the same. 

Background Science

First, let’s recap the basics. We know that humans have emitted and continue to emit enormous amounts of greenhouse gases into the atmosphere. These greenhouse gases are trapping heat from the Sun which is causing the planet to warm. This warming results in a number of harmful effects including rising sea levels, wildfires, increasingly severe storms, blah, blah, blah… you get it. 

What is Solar Geoengineering?

At its core, solar geoengineering, formally called Solar Radiation Management (SRM), is the field that works on limiting the amount of sunlight that reaches the surface of the Earth. This involves a combination of natural sciences and advanced technology to block solar radiation from even entering the lower parts of the atmosphere. The idea is that by keeping away this radiation, the warming effect could decrease global temperatures and, perhaps, suppress climate change. 

One of the main ways that solar geoengineering looks to make an impact is through Marine Cloud Brightening (MCB) which, according to David Keith’s Research Group at Harvard University, is “an albedo modification technique that aims to increase the reflectivity, and possibly even the lifetimes, of certain clouds to reflect more sunlight into space and partially offset some of the impacts of climate change.” In simpler words, MCB means making clouds brighter so that they can reflect more sunlight and allow less heat to reach the surface. Clouds already block sunlight but making them brighter would block it more effectively. This would be done by spraying sea salts into specific types of clouds, eventually leading to their brightening (only clouds on 10% on the planet’s surface are eligible for this technique). 

The other prominent form of solar geoengineering is Stratospheric Aerosol Injection (SAI), which is exactly what it sounds like: aerosols injected into the stratosphere (the second-most inner layer of the atmosphere). What it means is that a chemical such as sulfur dioxide (SO₂) will be sprayed into the atmosphere and will eventually turn into an aerosol once it interacts with certain pre-existing chemicals in the atmosphere. Aerosols, like clouds, block sunlight from reaching the Earth’s surface to an extent and will, therefore, serve the same purpose of reducing warming. (Fun Fact: This process already happens naturally when volcanoes erupt.)

Why Would We Use Solar Geoengineering?

As we discussed, solar geoengineering would reflect solar radiation back into space. But, why would we even want to do that?

Well, a lot of people believe that efforts to address climate change, including adopting clean energy, using electric vehicles, switching to climate-friendly diets, and restructuring agricultural processes will either not be enough to solve the problem or not happen in time. These people think that on top of making use of these solutions, solar geoengineering should be added to the mix as a way to directly reduce warming by allowing less heat from even reaching the surface and delay the effects of climate change. As you might have guessed, however, there are several other factors to consider before introducing such significant changes. 

Concerns

The truth is that we have the resources for solar geoengineering. For example, as stated in a BBC Future article, Stephen Salter, emeritus professor at the University of Edinburgh, “all the [global warming] damage we’ve done to the world up until now” could be undone with MCB and “would [cost] less than the cost to host the annual UN Climate Conference – between $100-$200 million each year.” So, if we have what we need, why aren’t we doing anything? 

Like anything else, solar geoengineering has a lot of layers. On the top, you see a way for global temperatures to be reduced and global warming to potentially be reversed. But it’s the underlying, and sometimes hidden, layers that make the subject so controversial.

One of the biggest concerns regarding solar geoengineering is that the “solution” is not actually a “solution” to climate change since the root cause (greenhouse gas emissions) is blatantly ignored. Solar geoengineering is almost like a sideways solution in the sense that it doesn’t solve the original problem, but attempts to solve the problem caused by the original problem. It’s kind of like if you were sick and your nose was running a lot and, instead of treating your sickness, you just blocked your nostrils with rolls of paper. While you may stop yourself from having a runny nose, that doesn’t take away from the fact that you are still sick, it just might take longer to notice. 

There is also a fear that lawmakers will focus too much of their attention on solar geoengineering and not on more viable solutions like clean energy and sustainable agriculture. People think that lawmakers will be attracted to the relatively low cost of geoengineering and its seemingly little impact on the general society. However, this is a blind approach since relying solely on solar geoengineering would allow greenhouse gases to continue to be emitted into the atmosphere while only the warming is somewhat controlled. Problems like extreme weather events, ocean acidification, respiratory issues, etc. will continue if greenhouse gas emissions go virtually unrestricted. This will simply grow the climate change bubble as it awaits its inevitable pop. 

Another concern related to solar geoengineering is the possibility of several adverse effects as a result of its implementation. 

Earlier in the post, we discussed Marine Cloud Brightening and how clouds can be brightened to reflect solar radiation. This issue is that, according to David Keith’s Research Group, this technique could “affect large scale climate and weather patterns if it were used on a large enough scale.” While the specific effects are currently unclear, it is the uncertainty that makes scientists wary. 

Stratospheric Aerosol Injection is pretty similar to MCB in the sense that there is not enough information on how SAI will affect the planet outside of potentially reducing warming. As stated in a Smithsonian article, scientists think that SAI might disrupt weather patterns, limit food supply by blocking sunlight, and even lead to ozone depletion due to the aerosol particles in the atmosphere. 

One thing is for sure: we don’t know enough about solar geoengineering. We think it could help us combat climate change but, with all these concerns, there is a lot of hesitancy in actually deploying these methods. In fact, David Keith, who I mentioned earlier, and Frank Keutsch were leading an experiment at Harvard called Stratospheric Controlled Perturbation Experiment (SCoPEx) which was basically SAI on a small-scale (you can read more about it here) and was planned for June 2021. However, Sweden, the country where the test was supposed to be performed, rejected the experiment due to ethical and environmental concerns. This just shows how much uneasiness lies under the subject of solar geoengineering.

Conclusion

In my opinion, solar geoengineering should be used more as a buffer than an actual solution to climate change, if used at all. It can be used in a way that would give us more time to address greenhouse gas emissions and rebuild the global infrastructure to be cleaner, but it can’t be the only thing we do. 

All in all, more research is needed. There is just too much uncertainty to really go into solar geoengineering with full force. We need to be confident that we can reduce warming without significantly harming the environment in other ways.