Is It Time To Invest In Sucking Mass Amounts Of Carbon From The Air?
Climate change is accelerating at an alarming rate. Without intervention, the world will a face serious existential crisis, possibly even within the next few decades. Fortunately, scientists are well aware of the problems and working tirelessly to find solutions. The Paris Agreement, which the United States just rejoined under the Biden Administration, calls for a goal of limiting warming to 1.5 degrees Celsius above pre industrial levels in order to keep the worst from happening. The problem is that the usual solution of cutting emissions isn’t likely to get us anywhere near that number. Perhaps it’s time for some unusual solutions...
What is a DAC Machine?
Direct air capture, or DAC machines, are facilities constructed to scrub CO2 out of the atmosphere. DAC facilities use giant fans to suck in air. Once inside, the air passes over special plastic surfaces, where it reacts with a chemical solution that binds to the CO2. The air is released back into the atmosphere, while the carbon remains behind.
Carbon Engineering is a company that has been developing this technology for over a decade.
What happens to the carbon?
Capturing the carbon is one thing, disposing of it is something else entirely. Fortunately, scientists are working on several options of what to do with the captured carbon.
Pump it underground: Theoretically, the carbon could be stored underground. The problem is that spending money to run the facility and then getting rid of the product doesn’t make a lot of economic sense. Government subsidies may make this a more feasible option.
Turn it into a new fuel: While putting the carbon back into the atmosphere seems counterproductive, it would meet the goal of making industries such as airlines and cargo ships that are reliant on carbon become carbon neutral.
Have other corporations pay to store it: Having corporations pay to have a DAC facility sequester CO2 underground on its behalf allows them to claim to be carbon negative or neutral. The positive of this approach is that it may encourage nations to subsidize the development of DAC technology, or buy their one DAC technology.
What would DAC look like on a large scale?
In a recent paper in the journal Nature Communications, researchers were able to demonstrate that deploying a wartime-style deployment of a global network of DAC machines is feasible. Ryan Hanna, an energy systems researcher at the UC San Diego and lead author on the paper explained that he and his colleagues sketched out a vision of what would happen if humanity invested in DAC like we’d invest in another world war.
They broke the modeling into three parts:
How much governments would need to pay for DAC plants
How fast the plant rollout could scale using already-existing energy supplies like hydropower
How global temperatures would change if a mass deployment of DAC facilities turned down the amount of CO2 hanging around in the atmosphere.
What the researchers found was that with an annual investment of between 1 and 2 percent of the global gross domestic product, humanity could create a DAC network to remove around 2.3 gigatons of CO2 annually by the year 2050. This is about 400 times the amount of CO2 humanity currently sequesters.
Will DAC machines be enough to reverse climate change?
Unfortunately, human activity has already done so much damage to the climate that DAC machines alone will not be enough. In order to meet the Paris agreement’s 1.5 degrees C goal by 2050, we actually need to remove around 5 to 9 gigatons of CO2 per year…. Which is considerably more than the 2.3 that DAC could remove.
What else can we do to lower the carbon in the atmosphere?
Cut emissions: Sucking carbon out of the air does not mean that we can continue pumping excessive amounts of it back in. Hanna’s team’s modeling found that even with a massive buildup of DAC networks, the world will be 2.5 degrees Celsius warmer by the year 2100 if we don't bring down greenhouse gas emissions. That means that, regardless of the future potential for DAC technology, in order for it to matter, humanity must act immediately to dramatically reduce emissions.
Naturally sequester carbon: Bolstering wetlands, stopping deforestation, and planting new trees are all ways that we can naturally sequester carbon.
Make more DAC facilities! While it would take around 800 facilities to remove 2 to 2.5 gigatons of carbon a year by 2050, we don't have to limit ourselves to that number. Aiming for 4,000 to 9,000 plants by the year 2075, and beyond 10,000 by the end of the century, would theoretically allow us to be sequestering up to 27 gigatons of carbon a year.
Hanna explains that “You have a really long, slow, gradual scale-up as the industry grows through 2050. Once it sort of grows to a massive size, then it's really easy to add a lot of plants quickly, because you have this huge industrial base for the industry.”
There are some unknowns that Hanna and his team are still assessing such as estimating how much energy the future plants might use, the complex and undetermined future of global politics, and how the performance of the system could improve and the costs of the systems decline over time.
Is a wartime deployment of DAC technology extreme?
While it may seem extreme to spend so much money on technology which has yet to be tested on a global scale, the truth is that we are in an emergency situation. Investing heavily now in DAC, in conjunction with a concentrated effort to reduce emissions, will help us secure something far more valuable than money: a sustainable future for future generations.