Methods That Can Help Earth from Rising CO₂ Levels

For millions of years, the earth has been perfectly good at absorbing CO₂. Our forests, seas, and streams suck the gas up acting as natural carbon sinks, that was until humans came along and tipped the scales.

We began burning fossil fuels on levels never before seen, and it’s bi-products rapidly changed the landscape for not just humans, but also for the animals that shared the planet with us. The rate we have been spreading these pollutants into our atmosphere, has only risen day by day, since there discovery. Our CO₂ emissions have risen from 1,600 million metric tonnes to 36,000 million metric tonnes since 1865.

By now, it is also clear that global warming must be limited to two, or even better 1.5°C for the survival of mankind. And despite our best efforts, that number is not declining. If we continue to burn fossil fuels at ever-rising rates. In our future, global warming would soon be up to 4°C warmer and the impacts of that would be catastrophic & the consequences may have to be paid by the future generations with their own lives. That why it is so much essential to emit less climate-damaging CO₂.

What if we could just suck the CO₂ right out of the air, undoing some of the damage that has been done? Well, in certain circumstances, this is already happening.

Methods such as Carbon capture and storage (CCS) has been around for years. There are a few main types of carbon capture, almost all of which happen’s at power plants, capturing the carbon that comes directly from the plant.

The first type is Post combustion ­carbon capture, in which the CO₂ is captured after the fossil fuel is burned. In this method, CO₂ is separated from the flue gas, which includes CO₂, water vapor, sulfur dioxides and nitrogen oxides, by bubbling the gas through an absorber column packed with liquid solvents, such as ammonia. In the most widely used system, once the chemicals in the absorber column become saturated, a stream of superheated steam at around 120°C is passed through it. This releases the trapped CO₂, which can then be transported for storage elsewhere.

The second type is Pre-combustion carbon capture,­ in this, the CO₂ is trapped before it's diluted by other flue gases. The fossil fuel is heated in pure oxygen, resulting in a mix of carbon monoxide and hydrogen. The carbon monoxide is reacted with water to produce carbon dioxide, which is captured, along with hydrogen. The hydrogen can be used to produce electricity, and the carbon dioxide is stored.

Pre and post-combustion carbon capture can prevent 80 to 90 percent of a power plant's carbon emissions from entering the atmosphere. The IPCC estimates that carbon capture and storage has the potential to make up between 10% and 55% of the total carbon mitigation effort until the year 2100.

However, this captured carbon has to be stored in someplace. Well, It is most often stored underground in a process called geological sequestration, which involves injecting CO₂ into underground rock formations. It is stored as a super-critical fluid, meaning it has properties between those of a gas and a liquid. When carbon dioxide is injected at depth, it will remain in the super-critical condition as long as it stays in excess of 31.1°C and at a pressure in excess of 72.9 atmospheres. Many times, the carbon dioxide is injected into a reservoir which previously trapped oil and gas, since those areas have natural rock formations that help to contain the carbon dioxide. While this might be an okay solution, no one knows for sure what the environmental impact could be if the carbon dioxide were to leak out into the environment in large quantities.

In some instances, leakage of carbon dioxide underground has been shown to increase plant mortality, reduce growth and create potentially severe localized damage to ecosystems. For this to be a viable, safe option, the carbon dioxide would need to remain stored for 100s of years, or even indefinitely, and the feasibility of this is not certain.

Methods such as storing carbon include sinking it deep below the ocean, at depths under 3.5 Km, where it turns into a slushy material that will sink to the ocean floor under that amount of pressure or Using another method like, Pumping CO₂ into the volcanic rock underground can speed up a natural process where the basalts react with the gas to form carbonate minerals, which make up limestone, would be helpful. But due to these methods are in the researching stage, there is uncertainty whether it is feasible or economical or most importantly the effects of its stores on the surrounding life.

The method of creating artificial trees is also emerging to the surface, where the trees made of CO₂ absorbing plastic, acts as a sponge and stores CO₂. This CO₂ is then separated with simple water where the plastic is simply soaked wet, which causes the plastic to give away captured CO₂  & this CO₂ is then stored for further use. The efficiency of capturing CO₂ of this artificial trees is also better than the natural trees and that they can be reused again and again. Where other carbon-capturing techniques use a lot of chemical & energy to separate CO₂ from the collector. Researchers estimated that artificial trees can capture up to 1 million tons of CO₂ per year. However, looking at our present situation, we might need to plant these artificial trees on a large scale to work, for this, we might need a lot of investment.

And while 80 to 90 percent of a power plant’s carbon emissions can, in theory, be captured and stored in one of many ways, what about all of the other carbon-emitting things in our world? Only 25% of global greenhouse gas emissions come from electricity and heat production at power plants. Transportation, general industry, and agriculture collectively make up around 60% of greenhouse gas emissions.

Recently a team of scientists from Harvard University and the Bill Gates funded company Carbon Engineering whose CEO is David Keith who is also a developer who developed numerous ideas in the field of geoengineering. For example, to produce artificial clouds to reduce solar radiation, Or to fertilize the oceans with iron so that algae that eat CO₂ multiply. Have recently announced that they have found a method to cheaply pull CO₂ pollution out of the atmosphere. They say for as little as $94, and for no more than $300 per metric ton of CO₂. This means that it would cost between $1 and $2.50 to remove the carbon dioxide released by burning a gallon of gasoline in a modern car. And not only do they suck the CO₂ out of the air with the ability to store it - they will also transform the carbon back into gasoline or jet fuel, creating net-neutral carbon-based fuels.

Carbon Engineering Plant in Cannada

Putting it simply, it works like this, First, the air is captured by huge fans and the CO₂ is absorbed by a hydroxide solution. This liquid is then converted into pure CO₂, which can be processed into gasoline or diesel together with hydrogen. This means the company can produce carbon-neutral hydrocarbons, meaning if you were to burn this fuel in your car, you would release carbon-dioxide pollution out of your exhaust and into the atmosphere. But because this carbon dioxide came from the air in the first place, these emissions would not introduce any new carbon dioxide to the atmosphere, and no oil would need to be extracted from the earth to power your car. And perhaps most importantly for the economic viability of this idea, they can sell the product, which helps to offset costs, allowing them to capture even more carbon dioxide, to either convert back into hydrocarbons or ultimately store.

But how much carbon can they realistically hope to suck out of the air? In 2017, the world emitted about 32.5 gigatons of CO₂. If this technology were built at a scale to suck all that back out of the atmosphere at $93 to $300 per ton, simple math shows that the total cost would be between about $3 trillion and $7.5 trillion.

For this idea to work globally in pulling substantial amounts of CO₂ from the Earth’s air, there would need to be hundreds or thousands of scaled-up plants producing hundreds of thousands of barrels of carbon-neutral fuel to drive down costs further, in the same way that solar and wind energy costs have plummeted over the past decades with increasing scales.

However, to keep global warming to less than 2°C, the international target to avoid the most dangerous impacts, we will need negative emissions, not carbon neutral emissions. We need carbon to be taken out of the atmosphere and stored permanently, or the problem will only plateau indefinitely. But the reality of the situation is that when you are only capturing and storing carbon, there is no market for that. The only way to pay for carbon being captured from the air and stored, on a large scale, would be government subsidies, and to rely on only our governments to solve this problem is certainly a mistake.

And if Carbon Engineering is making fuel from their captured carbon, this is only a carbon-neutral plan. Thus, introducing the idea of selling back the carbon as fuel is a way to fund such an effort. With market demand and money coming in, companies like Carbon Engineering can improve their technology, expand operations, store some carbon, and work toward making sure that less oil is extracted from the ground over time. Critics say that we should simply just not be taking the carbon out of the ground in the first place, focusing on reducing emissions rather than capture and storage, or capture and re-use. And some worry that technology like this will allow us to think that we have no responsibility to reduce emissions. And it is cheaper to not emit a ton of CO₂ in the first place than to capture it.

While these are all definitely valid points, technology like this can and should play a role in how we tackle climate change. It’s unrealistic to think that every industry, every consumer, and every government in the world will change their behavior in time to tackle the rising global temperatures, as much as we wish they would.