6 min read

A guide to buying Carbon Removal offsets

I'm going to explain what is a carbon removal offset (as opposed to carbon avoidance offset), what makes a good quality offset and give you a list of companies to buy from.
A guide to buying Carbon Removal offsets
Photo by JD Andrews / Unsplash
I've made it even easier for you and created a database with the only companies that you need to buy removal from. Get it from here: https://store.carboncaptureexplained.com/l/carbon-removal-database


09.01.2022: Added section about voluntary markets 

Offsetting your carbon footprint has traditionally involved buying some offsets from a project that plants trees, or protects a forest or is using renewable energy. The "problem" (quotes, because they're still a better option than doing nothing) with these types of offsets is that they are not permanent, they don't remove carbon dioxide from the air and are sometimes even not accountable.

In this post I'm going to explain what is a carbon removal offset (as opposed to carbon avoidance offset) and help you decide where to buy from.

What makes a Carbon Removal offset?

As it name suggests, an offset that is bought from a carbon removal project actually removes CO2 from the atmosphere and stores it in a (semi-)permanent way. Examples include:

  • Direct Air Capture with geological mineralization, where technical plants are chemically capturing CO2 from the air, then store it underground where it gets mineralized and stored there for millennia.
  • Biochar, where biomass is burned in high temperatures with lack of oxygen thus producing a charcoal-like object that can improve soil fertility and keep its carbon stored for centuries.
  • Injecting CO2 in cement, storing it there for centuries and increasing its structural integrity.
  • Building wooden buildings.
  • Growing seaweed in the open sea and sinking it in the deep ocean floor.

You can read more details about these examples in my previous article about carbon capture and removal.

The alternative to that, which is the current mainstream way of buying offsets, is related to carbon avoidance offsets where examples include:

  • Tree planting. One might argue that trees remove CO2 from the air but with the higher risk of fires and natural decomposition they're not so permanent - more on that below on Durability.
  • Forest protection. Similarly, more on that on Additionality.
  • Carbon utilization, like creating algae based products instead of oil-based ones (plastics, cosmetics).
  • Using renewable energy which, like above, replaces fossil fuels.

Quality Criteria

Before you buy carbon removal offsets, there are some criteria that can help you understand what is considered a high-quality offset, which are:

  • Durability, which is probably the easiest to grasp as it pertains to the time period that the carbon is sequestered. As said, trees release the carbon back to the atmosphere either by natural decomposition or by fires, so they tend to have low durability compared to geological sequestration which, by the way, is not permanent as theoretically in could resurface via geological mechanisms some millions of years later and release the carbon back to the atmosphere. This is also the reason why we're talking about durability and not permanence. So, a rule of thumb is that forests last for decades, biochar for centuries, mineralization and sequestration for millennia - considering that we need to achieve meaningful change within our lifetimes, it's safer to invest in century scale and above.
  • Leakage, where if you protect a forest in one place but your actions lead to another one in another location being cut down, then that's leakage. As little leakage as possible, the better.
  • Verification from third party services is why you don't have to worry about the above, which is also impossible to track as a consumer. Look for something like that in marketplaces where independent third party verifiers can take care of the paper work or look at where big companies like Stripe and Microsoft buy their offsets from (and, again, more on that below).
  • Additionality, which is a tricky one. It means that the offsets you purchase are only happening (avoidance or removal) because you paid for them. If a forest is not in risk of being cut down or burned, you can't go and claim carbon offsets for it and sell them. That's not a hypothetical scenario but a real story where Natural Conservancy, the world’s biggest environmental group, sold meaningless offsets to JPMorgan, Disney, and BlackRock.
JPMorgan helping preserve the forests of the world

Ok, now show me the companies

Right, so this is where I'm telling you that it's going to be hard to buy removal offsets from these companies because, first, there's not a lot of them (in the upper double digits as of 2021) and, second, you have to compete with companies like Microsoft and Stripe (the links point to their climate change actions) in buying them.

In fact, in my research I looked specifically into these two companies' carbon offset purchases because they have the work of internal big teams and outsourced researchers that can verify the offsets in terms of the criteria I listed above, so you can rest assured that these companies are legit.

After that:

  • I then created a list of the projects that have a 100+ years sequestration durability potential, as it's listed in this great CDR database from carbonplan.org.
  • I filtered out the ones that don't have a website or an easy way to get in touch with them. I got in touch with the remaining (more than half of them didn't even bother replying) and corrected some of their contact information.
  • I listed them in the database that you can find below. The price per ton was taken from the Carbon Plan database which in turn got that information from Stripe's public reports - as they purchased large quantities they probably got a better deal than what you might achieve but you can get a sense of the costs. Wherever the price is missing, it was not shared.

Buy from voluntary markets

The above table is useful if you want to get in touch with them directly to negotiate quantities and prices or, where allowed, to buy directly from their sites. Currently, only two of them offer that:

After having talked to some of these companies, I realized that in their current stage of development it's more beneficial do B2B sales internally and outsource B2C in voluntary marketplaces.

I'll list the three marketplaces that I found which have carbon removal offsets but do let me know at hello@carboncaptureexplained.com if I missed any.


puro.earth is a marketplace that only lists carbon removal projects. You will find many duplicates with my list and almost all of them are sold out (there is some availability only in some wooden building projects and their not-yet-verified projects list that they call "pre-CORC") but they seem to be doing a great work in terms of filtering out the noise, properly certifying your offsets and allowing you to easily purchase with a credit card.

Carbon Future

carbonfuture.earth take a slightly different approach in that they aggregate many different projects and open up some credits every quarter. Unfortunately, at the time of writing this article they are all sold-out.


wren.co have recently added two removal projects in their list (they used to have carbon avoidance offsets):

  • A Biochar project
  • A Mineralization project, which is actually from the Future Forest company mentioned above

As a closing thought, I'd like to iterate the importance of carbon removal projects. Decarbonizing is not enough, we will need to remove carbon from the atmosphere on top of reducing our emissions and projects like these, while more expensive than the rest, they express the right path forward and need that money more in order to develop, scale and eventually become cheaper.

Let me know if you have any questions or if you're a company that is selling carbon removal offsets and would like me to add you to the list.