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Why We Must Remove Carbon Dioxide from the Atmosphere

Every day, 300 million tonnes of carbon dioxide (CO2) are emitted into the atmosphere, or 40 billion tonnes a year. Is that a lot? In short, yes. Human-caused emissions have added up to over a 50% increase in CO2 levels in the atmosphere since pre-industrial times.

Even if we were to halt emissions completely now, that excess CO2 is already out there warming the planet. Unless we want to, in the words of the European Academies Science Advisory Council, “condemn humanity to a dangerously warming world”, we must find ways to remove CO2 from the atmosphere in massive quantities.

The climate on this planet matters. It affects our ability to grow food, access water, and live here. The climate has been heavily politicized, but like the COVID-19 virus, the Earth doesn’t care about our preferred candidates or political views. It responds according to the laws of physics, and the way it responds to our activities affects us all. So let’s deal in facts and solutions.

There has been a growing discussion of the need for the removal of carbon dioxide. For a long time, the topic was taboo.  Why? “Moral hazard”. If people know we can remove carbon dioxide, they will not cut their emissions. Or so the argument goes. We’ll return to this later, but for now suffice to say that it is far too late to address this problem by cutting emissions alone. Removing carbon dioxide from the atmosphere is needed. The moral hazard argument is decades out of date.

Taking a step back, here are a few simple facts about the current state of the climate and how we got to this point.

  1. The recent rate of increase of carbon dioxide levels in the atmosphere is unprecedented.

Humanity has emitted about a trillion tonnes of extra carbon dioxide into the atmosphere since the industrial revolution.

Over geological time, carbon dioxide levels in the atmosphere have risen before. What’s different this time is that they are shooting up 10-100 times faster than they ever have before. Levels are now higher than they have ever been in about 3 million years. The planet has natural ways to stay in balance, but these cannot act quickly enough to compensate for how quickly we humans are changing things.

CO2 Parts Per Million Chart
  1. This matters because it’s changing our world in ways that are harmful to us.

Three million years ago when there was this much CO2 around, sea levels were 50-80 feet higher. A warmer world means higher sea levels because of melting ice and because water expands when it warms. This is putting coastal cities around the world at risk. Extreme weather events have become more commonplace, with more hurricanes and fires, and millions of people displaced because of droughts and failing crops. The sea level has already risen over 1 foot, and that’s just the beginning.

New Jersey Coastal Flooding

And the ocean, which has absorbed much of the CO2 we’ve emitted, has become warmer and more acidic as a result, contributing to the widespread death of corals, shellfish, and other creatures. This is not just a problem for sea creatures and the scuba divers who want to look at them: the oceans are an enormous food source for humanity, and without healthy ocean ecosystems, fishery yields will continue to plummet.

State Department Fish Protein Stats

We have a collective global problem on an unprecedented scale.

  1. Something needs to be done – but what, how, and when? And what will it cost?

First, what needs to be done, and how quickly?

The only path to avoid catastrophic future scenarios is to transition to a world with much lower levels of CO2 in the atmosphere. To do that, we need to end our reliance on fossil fuels. Since most electricity generation and almost all transportation currently burn fossil fuels, this will be hard. However, it can be done. Renewable sources of energy such as solar power are becoming competitive with fossil fuels. Electric cars are early on the path to being mainstream. Coal power is already falling precipitously.

As I said, this will be hard. It will take time. The Paris Agreement, signed in 2016, is a global plan to reduce emissions. 196 countries signed up. The climate is a classic example of the free-rider problem: the costs of transitioning to a low-carbon economy are borne at the individual and national levels, whereas the benefits accrue globally. Even at the national scale, if one country plays its part while others do not, the problem remains. This is why securing the agreement of so many nations to play their part in addressing this global crisis was such a momentous achievement.

Reducing emissions is necessary, but not enough, for two reasons. First, reducing emissions in ways that preserve the global economy will take at least two decades, likely three. In that time, even with emissions reducing, carbon dioxide levels will continue to climb to levels which will push the climate towards a deadly tipping point from which it will be difficult or impossible to return. Second, there is the excess carbon dioxide already sitting in the atmosphere and oceans. Suppose I come around to your house and start smashing everything in sight with a sledgehammer, you’ll probably become angry and ask me to stop. If I then set the sledgehammer down and calmly take a seat on the couch, you’ll probably still be upset at me. I haven’t fixed any of your carefully-chosen ornaments, only stopped destroying them. It’s like that with carbon dioxide too. We need to return CO2 in the atmosphere to healthy, sustainable levels, not just stop doing the damage.

Enter Carbon Dioxide Removal (CDR)

This leads us to the need to remove carbon dioxide from the atmosphere, often called Carbon Dioxide Removal, or CDR. The only way we can keep this planet a healthy place to live is to do it. We need to let go of any negative associations we have with this idea. Yes, it would have been better to avoid this problem in the first place, by making the transition to a low-carbon economy decades ago. We didn’t do that, and we don’t have a time machine, so it’s time for us all to accept CDR for what it is – a necessary and critical part of the solution. Some people have criticized CDR on the basis that it reduces the incentive for us to make the switch to a low-carbon economy, but CDR is now a required part of the overall solution.

The chart below shows the large gaps between the current trajectory of increasing emissions and the path we need to follow, even if countries meet their non-binding Paris Agreement targets. The figures in the gray circles show how much CO2 we must remove from the atmosphere to keep global warming below the generally recognized targets of 1.5 and 2 degrees C above pre-industrial levels.

Intergovernmental Panel on Climate Change Global Greenhouse Emissions Chart

We need to start removing somewhere between 13 and 32 billion tonnes of carbon dioxide per year by the end of this decade. Given that we are currently at close to zero CDR, we must move as quickly as possible.


Any method of CDR creates its own carbon emissions, which must be taken into account in a ‘life cycle analysis’ (LCA) to determine the net effect. This is the first hurdle: a process must remove more CO2 than it emits.

Second, there is little point in capturing relatively small amounts of CO2. CDR methods need to be able to remove gigatonnes of CO2 per year to make any sort of dent in the problem.

Third, CDR methods should capture CO2 permanently, locking it up for hundreds of years at least.

Fourth, economic viability is essential. This means CDR methods must either be profitable in themselves, typically because they create a by-product which can be sold, or they must be cheap enough to solve the problem while drawing on a relatively modest proportion of society’s economic resources.

Fifth, it must be safe and preferably provide ‘co-benefits’ as well. Much has been written about the risks of ‘geoengineering’, ranging from the philosophical argument that we are ‘playing God’ to concerns about the impacts of specific interventions. The reality is we have already affected the climate, so the concern about playing God has little logical merit. The safety of each CDR method must be carefully analyzed though, to make sure we don’t cause deeper problems than the ones we solve.

As of now there are no methods which have been shown to meet the five criteria above. There are lots of possible ways to do CDR, and as a society we should explore all which have a reasonable chance of working. We don’t have time to waste and the magnitude of the problem means there are no silver bullets.

Why don’t we just plant trees? Trees are great: a natural and cheap way to capture CO2 and prevent erosion. But trees alone cannot solve this. There simply isn’t enough land available for the number of trees we’d need, and in many cases CO2 is captured only temporarily.

The Project Vesta Plan

Project Vesta Turning the Tide on Climate Change Banner

At Project Vesta, we are working on a promising solution. It’s a way to accelerate a natural process and remove carbon dioxide cheaply from the atmosphere at a massive scale and turn it into rocks. There’s a natural process that’s existed for billions of years: when rain falls on volcanic rocks, CO2 is captured. After a series of steps it ends up as sediment on the bottom of the ocean, where it turns into limestone.

The problem is, this process is slow, but the good news is that we can speed it up. To do so we need to break down the rocks, so we take a green volcanic rock called olivine, grind it into sand, and spread it on beaches. There, wave action breaks it down, pulling CO2 out of the air and de-acidifying the ocean at the same time. Because we use natural wave energy to do this, we capture 20 times more carbon than we emit in the process of making these beautiful beaches.

Thirty years of peer-reviewed scientific papers, including various laboratory experiments, show that this process works. What we need now is real-life experiments at pilot beaches to demonstrate that the process works. After these, our open-source approach will ensure that this can be scaled up rapidly and globally. We believe global deployment could begin within 3-5 years, creating the fastest possible path to capturing and permanently removing 100 percent of humanity’s annual CO2 emissions.

And the cost? We can remove 100% of humanity’s emissions for under $500 billion per year. This is a large amount of money, but it’s only 0.3% of global GDP. That is a tiny investment compared with the cost of doing nothing. If we do nothing, we’ll need to deal with billions of displaced people; imagine the cost of moving New York City or London to higher ground and you start to get an idea of what this would take.

In conclusion

There are numerous other possible solutions, from using similar rocks to capture CO2 in soil to pulling CO2 directly out of the air using fans and chemical reactions. Project Vesta believes that as a society we should investigate any solution which has a reasonable shot at meeting the five criteria outlined above, and focus our resources on the solutions which show the most promise.

There is much cause for optimism. As a species we have great reserves of ingenuity, and paths remain open to avoid ruining this planet for ever. We can solve this problem, but only if we try hard, and only if we do so now.