[This is a transcript of the video embedded below.]

Elon Musk has announced that he is sponsoring a competition for the best carbon removal ideas with $ 50 million in prize money for the winner. The competition opens on the twenty-second or twenty-first of April. In this video, I’m going to tell you everything you need to know about carbon sequestration to get your brain going and get you on your way to $ 50 million.

During the formation of our planet, large amounts of carbon dioxide were stored in the soil and ended up in coal and oil. By burning these fossil fuels, we very suddenly released a lot of that old carbon dioxide. It accumulates in the atmosphere and prevents our planet from giving off heat like it used to. As a result, the climate is changing and it is changing rapidly.

The best course of action would have been to not pump as much carbon dioxide into the atmosphere initially, but at this point reducing future emissions alone may no longer be the best way to continue. We may need to find ways to actually get carbon dioxide out of the air. Achieving this is what Elon Musk’s competition is about.

The problem is that once carbon dioxide is in the atmosphere, it stays there for a long time. Through natural processes alone, it would take several thousand years for the atmospheric carbon dioxide content to return to pre-industrial levels. And the climate is slow to respond to the sudden surge in carbon dioxide so we haven’t seen the full effects of what we’ve already done. For example, there is a lot of water on our planet and warming up this water takes time.

Even if we stopped carbon dioxide emissions completely today, the climate would continue to change for at least a few decades, if not centuries. It’s like you’ve voted someone out of office and now you’re really pissed off, but you have six weeks on the job and nothing you can do about it.

Worldwide, we currently emit around forty billion tons of carbon dioxide per year. According to the Intergovernmental Panel on Climate Change, we would have to drop to 20 billion tons per year to limit warming to a point of five degrees Celsius compared to pre-industrial levels. This one point five degrees is the so-called “Paris goal”. This means that if we continue to emit at the same level as we do today, we will have to remove 20 billion tons of carbon dioxide a year.

But to score in Musk’s competition, you don’t need a plan to remove the full 20 billion tons a year. All you need is “a working prototype for carbon removal that can be rigorously validated” that can “remove at least 1 tonne per day” and the carbon “should be locked in for at least a hundred years”. But otherwise pretty much anything goes. According to the website, the “main metric for competition is cost per ton”.

What are our options for removing carbon dioxide and how much do they cost?

It is obvious that we can improve natural processes that remove carbon dioxide from the atmosphere. You can do this, for example, by planting trees because trees absorb carbon dioxide as they grow. They are a so-called natural “carbon sink”. This carbon is released again when the trees die and rot or are burned. Planting trees alone is not enough, we would have to increase their number permanently.

At what time? It depends a little on the type of forest, but to get rid of the 20 billion tons a year we would have to plant about ten million square kilometers of new forest. That’s roughly the size of the United States and more than all of the remaining Amazon rainforest.

Planting so many trees seems a bit impractical. And it’s not cheap either. The cost is roughly $ 100 per ton of carbon dioxide. To get rid of the 20 billion tons of excess carbon dioxide that would be a few trillion dollars a year. Trees are clearly part of the solution, but we have more to do. And stopping burning the rainforest wouldn’t hurt either.

By the way, humans are also a natural carbon sink because we are eighteen percent carbon. Unfortunately, burying or burning the dead returns that carbon to the environment. In fact, a single cremation releases around two hundred and fifty kilograms of carbon dioxide, which could be avoided, for example, by throwing dead people into the deep sea where they won’t rot. So if we were to conduct burials at sea instead of cremations, it would save up to a million tons of carbon dioxide per year. Not very much. And probably pretty expensive. Yes, I am not the person to win this award.

However, there is a more efficient way that oceans can help remove carbon. When you stimulate the growth of algae, they take up carbon. When the algae die, they sink to the bottom of the ocean, where the carbon could, in principle, remain for millions of years. This is known as “ocean fertilization”.

In theory this is a good idea, but in practice it is currently unclear how efficient it is. There isn’t good data on how many algae sink and how many of them are eaten. If so, the carbon could be released and no one knows what else such fertilization could mean for the oceans. So much remains to be explored here. It’s also unclear how much it would cost. Estimates range from $ two to four hundred and fifty dollars per ton of carbon dioxide.

In addition to improving natural carbon sinks, there are a variety of technologies for permanent carbon removal.

For example, if you burn agricultural waste or wood in the absence of oxygen, it doesn’t release all of the carbon dioxide, but creates a substance called biochar. The biochar holds about half of the carbon and is not only stable for thousands of years, but can also improve soil quality.

The main problem with this idea is that there is only so much agricultural waste to burn. According to some optimistic estimates, up to one point this could remove eight billion tons of carbon dioxide a year. The cost estimates are between thirty and one hundred and twenty US dollars per ton of carbon dioxide.

By the way, plastic consists of around eighty percent carbon. That’s because it’s mainly made up of oil and natural gas. And since it’s non-biodegradable, it will safely store the carbon – as long as you don’t burn it. So, the garbage dump in the Great Pacific? That is carbon storage. Not particularly popular.

A more popular idea is improved weathering. For this purpose, certain minerals are created artificially, which bind carbon dioxide to them when they come into contact with water and thus remove them from the air. The idea is to produce large quantities of these minerals, crush them, and distribute them over large areas of land.

The challenges for this method are: How do you produce large quantities of these minerals and where can you find enough land to plant them? Proponents of the American weathering project Vesta claim the cost would be about ten US dollars per ton of carbon dioxide. So that’s ten times less than planting trees.

Then there is a direct air collection. The most common method of doing this is by forcing air through filters that absorb carbon dioxide. Several gasoline companies such as Chevron, BHP, and Occidental are currently exploring this technology. Carbon Engineering, backed by Bill Gates, has a pilot facility in British Columbia that is expected to expand to commercial facilities. They claim that each such plant is equivalent to 40 million trees in carbon removal and removes 1 million tons of carbon dioxide per year.

They estimate the cost between ninety-four and $ 232 per ton. That would mean between $ 2 and 4 trillion a year to eliminate the entire 20 billion tons of carbon dioxide we need to get rid of. That is between two and five percent of global GDP.

However, since carbon dioxide is absorbed by the oceans, one can also try to get rid of it by extracting it from seawater. In fact, the density of carbon dioxide in seawater is about one hundred and twenty-five times higher than that in air. And once you remove it, the water picks up new carbon dioxide from the air, so basically you can use the oceans to suck the carbon dioxide out of the atmosphere. That sounds really neat.

The current cost estimate for extracting carbon from seawater is around $ 50 per tonne, which is about half the amount of carbon extracted from the air. The greatest challenge for this idea is that the currently known methods of extracting carbon dioxide from water require the water to be heated to around seventy degrees Celsius, which uses a lot of energy. But maybe there are other, more energy efficient ways to get carbon dioxide out of the water? You could be the person solving this problem.

Finally, there is carbon capture and storage, meaning carbon dioxide is captured right where it is produced and it is stored before it is released into the atmosphere.

About 26 commercial establishments are already using this method and a few dozen more are planned. In twenty-twenty this method captured about forty million tons of carbon dioxide. The typical cost is anywhere from $ 50 to $ 100 per tonne of carbon dioxide, although in particularly fortunate cases the cost can drop to around $ 15 per tonne. The main challenge is that current carbon capture and storage technologies require large amounts of water.

As you can see, a common problem with these ideas is that they are expensive. So you can compete with Musk by making any of the existing technologies cheaper or more efficient, or both, or you may have a whole new idea to come up with. I wish you luck!


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