The Science Behind Carbon Removal Technologies
Our planet is warming at rapid speeds. From landslides to extreme storms, we’re already feeling the dire outcomes of global warming. In 2015, 10 weather and climate disaster events such as floods and wildfires, have costed over $1 billion in property losses.
195 countries signed what’s known as the Paris Agreement —global leaders working together in order to eliminate greenhouse gas (GHG) emissions by 2050, and to do that we need to reduce and remove 40 gigatons of CO2 to get to net-zero. There are many different technologies that can accomplish this, such as direct air capture, CO2 mineralization, and also organic methods like seaweed and bamboo.
Direct air capture is a technology that directly captures CO2 from the air and stores it underground. Carbon Engineering’s technology pulls in the air, and extracts the CO2 in a process similar to how trees and plants photosynthesize. A potassium hydroxide solution binds the CO2 to the liquid, turning it into a carbonate salt, which can be stored permanently underground. While huge progress has been made in this field, it is currently not efficient or cost-effective to be viable. At scale, Carbon Engineering says that they can get the cost down to $100 per ton of CO2 removed.
CO2 mineralization is the process when raw carbon in the atmosphere turns into solid minerals. It works by exposing carbon dioxide to rocks called ultramafic rocks, and it binds the carbon into the rocks, trapping it permanently. Rock types that have huge potential are ultramafic rocks and basalt, and studies have shown that these types of rocks have the fastest reaction time to mineralize carbon. Our planet provides us with an abundance of basalt, it accounting for 90% of all volcanic rock. Some companies like CarbonFree and Heirloom convert the mineralized carbon into materials like baking soda. Heirloom takes it one step further and creates building materials that can be used in highways or offices.
Seaweed (and other fast-growing plants like bamboo) play a huge part in reducing and removing greenhouse gases and the atmosphere. Not only does it suck CO2 out of the atmosphere from photosynthesizing, it also restores the ocean biodiversity and helps with acidification caused from global warming. It bolsters the defense of the coast and decrease erosion. Seaweed can also be profitable, from selling it to markets or farms. Seaweed is thought to withdraw 220 million tons of CO2 each year — about as much as New York’s yearly emissions.
One of the major greenhouse gases is methane, and 37% of it comes from agriculture such as cattle. Even though methane only accounts for 16% of the total GHG’s emitted in a year, it has more than 80 times the warming power than CO2 in short-term. In a special type of seaweed called Asparagopsis Seaweed, there is a special type of enzyme called bromoform. In the cow’s stomach, bromoform works by “disrupting” the enzymes of gut microbes, which produce methane gas in burps and waste. Multiple trials conducted in the USA have shown up to 90% reduction of methane emissions. While all seaweed produce bromoform, Asparagopsis are the only types to be actively create bromoform as a defense mechanism.
Red seaweed is only native to Australia and Hawaiian Islands, and introducing it to places like Europe and Asia would be very beneficial. I’ve gotten super interested in how a simple oceanic plant can suck 200 times more carbon out of the atmosphere can advanced and complex technologies.
I recommend reading these articles if you want to learn even more about carbon removal techs!
