It’s common knowledge that climate change is on a course to damage life on Earth. Melting ice caps and the conditions possible for terrible forest fires, tsunamis, and floods are some of the biggest dangers of this menace.
Carbon dioxide has long been recognized as the major culprit in climate change because it traps heat inside the Earth’s atmosphere. Methane, which is emitted from fracking, actually traps 20-25% more greenhouse gases than CO2. But the current focus on reducing CO2 is due to the fact that there is much more carbon dioxide in the atmosphere than methane.
However, it is becoming an increasingly agreed-upon outlook that reduction measures alone will not be enough to stop the problem. While reducing CO2 emissions through cutting down on the burning of fossil fuels, switching to electric cars, biking more, etc., will help, it will not stop the problems facing us in the area of possible climate change disasters.
If the amount of CO2 and other greenhouse gases already in the atmosphere have reached a dangerous tipping point, the logical next step would be to explore how to take CO2 out of the air. Now, that’s not just a far-fetched idea, but an entire field of current research called geoengineering. This new term refers to efforts to develop a technology to take greenhouse gases out of the air and/or to cool the atmosphere.
Geoengineering falls into two major categories, Carbon Dioxide Removal, and Albedo Modification. Within those major classifications are several distinct methods of reducing greenhouse gases.
Carbon Dioxide Removal
- Direct Air Capture: Direct Air Capture uses banks of large circular fans to pull air across liquids that absorb CO2. It is then converted to a carbonate solution. This solution traps the carbon. It’s your high school chemistry class in action, with a bit of mechanical engineering thrown in. This method is still being refined and isn’t yet in wide use.
- Carbon Capture and Storage: This method can be thought of as a variation of direct air capture. It’s just a matter of what happens to the carbon dioxide once it is captured. In a way that sounds like it came from a futuristic movie, this method takes CO2 right after it poofs out of the smokestacks of factories and similar sources. After thus capturing the dangerous stuff, the process then scrubs the carbon. (There are, in theory, other methods, but this is the one being used to date). This process uses substances that bind to the CO2 and compress it. It then is sent underground, which is the storage (or “sequestration”) part of the concept.
In some cases, the CO2 is in liquid form. After being captured from a power plant, it then goes by pipeline to a drilling site. It is then injected into the ground, where it finds a home in rock formations far underground. Here, the liquid CO2 is pressed upon by the layers above it, and that pressure keeps it in its liquid form and in place. In other words, it would be taking the harmful substances from the air and burying them underground where they no longer can trap heat.
Within the capture and storage category, there are other ways of storing the carbon. One is called mineral carbonation, which is a very clever and fascinating process. It’s not just storing carbon but actually transforming it. The carbon is exposed to either magnesium oxide or calcium oxide. This produces a compound like magnesium or calcium carbonate (limestone). At this stage, the CO2 is not available to waft into the atmosphere and is harmless. The oxides listed above that are necessary for this process are more than abundant in the Earth’s crust.
Another form of storage would be storing the carbon at great depths in the ocean. After the carbon is captured through one of the methods above, it would be transported through pipelines (or possibly ocean liners) to a sequestration site. It would be blasted into the ocean. There, it disperses and does no harm.
As of now, ocean storage hasn’t been tried. However, there’s a sort of “proof of concept” to be found in the fact that oceans already absorb excess CO2 from the atmosphere.
Albedo is the light that is reflected from the Earth (or from another celestial body). Thus, when we look at albedo modification, we can see that it revolves around bouncing sunlight back into space rather than letting it into the atmosphere. So, while carbon capture is more reactive, albedo modification is preventative. Now, that doesn’t mean that one category of removal is better than another; rather, this distinction is just a way of clarifying the concepts.
But here’s one main similarity: as with carbon removal, albedo modification is a larger category to be broken into various specific operations.
- Aerosol Injection: Also known as “stratospheric aerosol injection,” this is a somewhat controversial new possible solution. There are materials such as Sulphur dioxide that would form a barrier just above the stratosphere (the upper part of the atmosphere). Injection refers to sprinkling sulfur dioxide or other similar inorganic materials into the air. Some ways to do this that are now being explored include dropping the substances from airplanes and—this is fun—blasting them from artillery guns. How great would it be to be the man or woman who gets to fight off global warming with a big gun? However, aerosol injection is not without a little controversy. When you blast powerful chemicals into the sky, there will be consequences. When you decrease the amount of sun coming in, that will also have consequences. There is a suggestion that the decreased sunlight would lead to droughts in Asia and Africa. One can conclude that further research is necessary to find possible side effects of deploying aerosols in this way.
- Marine Cloud Brightening: This is another fascinating, movie-like theory. Marine clouds are those that hang above oceans. Many of these are a dark gray. If we sprinkled drops of seawater it would lighten the clouds, enabling them to better reflect sunlight.
Is Geoengineering Necessary?
Until the last few years, when people talked about climate change, they touted the need to cut down emissions. A lot of people took great pride in switching to hybrid cars, suffering through the heat in the summer rather than regularly running an air conditioner, carpooling, recycling, etc. These things are still in place and should be done. But it is increasingly looking like valiant efforts by everyday people won’t result in reducing global temperatures enough to prevent catastrophes.
In 2017, global temperatures were 0.48°C (0.86°F) higher than the average from 1901-2000. These high temperatures were actually just a bit lower than those from 2014-16 when each year set a record for the highest temperatures on record.
To look at some specific examples, temperatures at the North Pole were twenty-three degrees higher than normal in 2016; parts of the Arctic Circle were 35 degrees higher.
The International Panel on Climate Change (IPCC) has set a goal to reduce global temperatures to only 1.5°C higher than pre-industrial numbers. (The above numbers compare current temperatures to those from 1901-2000.) But pledges that various world governments have made have us on pace to be between 2 and 3 degrees going forward in the century.
If electric cars were affordable and being bought at an increasing clip; if solar and wind and hydro energy were widely used and helped by a full infrastructure, then it would be easier to be optimistic about solving the climate change crisis without more drastic measures. But we’re far behind where we should be in these regards.
As a result, geoengineering measures are likely needed. Some of them, such as capture and storage methods, may need only some refinement. Some others may prove riskier, and it may be the case that when they are rolled out, they will reveal bugs to be addressed. The urgency for climate change remedies is growing, and geoengineering solutions will increasingly be considered by policymakers.