Google and others have paid millions of dollars for rocks scattered across fields that will supposedly remove CO2 from the air.

The young American company Terradot has just received a $27 million tranche for a pilot program in Brazil to naturally remove CO2 from the air. For this amount, several thousand tons of basalt stones from nearby quarries will be scattered across the fields of Brazilian farmers. It is believed that crushed rock will speed up the weathering process and bind carbon from the air into insoluble sediment. True, the financial side was taken from the ceiling.

Image source: Terradot

Terradot, the main initiator of projects of this kind – the Frontier Foundation and technology companies that wanted to pay in this way for increasing the energy consumption of their data centers, does not have an economic justification for the effect of sequestering carbon dioxide by accelerating basalt erosion. To simplify the calculations, we assumed that capturing one ton of CO2 in this way would cost $300, which is what all further actions are based on. Therefore, the contract to capture 90 thousand carbon dioxide was valued at $27 million. Separately, Google entered into an individual contract to capture 200 thousand tons of CO2 in this way.

Google did not disclose the cost of the individual contract with Terradot, but suggested that the cost of sequestering each ton of carbon dioxide would be less than $300. However, even these additional volumes will not compensate for all the damage that Google servers caused to the environment during 2023. According to conservative estimates, the company was responsible for 14.3 million tons of CO2 emissions last year. To compensate for such a volume, completely different contracts are needed. But it is much more logical to prevent this from happening, although this is impossible today.

Returning to the economic justification for the stone project, we note that Google and Terradot agree that there is insufficient data on this issue. But their logic is based on the fact that until you try, you won’t know. During the weathering process, basalt releases magnesium and calcium, which bind CO2 and convert it into the insoluble form of bicarbonates. The finer the basalt chips, the faster the reactions. At the same time, the experiment in Brazil is good because it is humid and warm, which accelerates weathering and carbon sequestration.

Then the carbon dioxide bound in this way should be carried out by groundwater into the ocean, where it will be locked up for millions of years. A field experiment on the weathering of basalt in farmers’ fields in Brazil will allow us to calculate the approximate volumes of compounds formed in the soil and the dynamics of their leaching from it, although it is not yet possible to estimate the substance carried into the ocean due to the lack of methodology.

As for farmers, by adding basalt chips to the soil they will be able to regulate its acidity. In theory, it will not interfere with growing plants, although, again, the dynamics of carbon dioxide sequestration will greatly depend on the volume of fertilizer application and a number of other factors. So for now, this is a large-scale experiment and a way for Google, H&M Group, Salesforce and others to make amends to society for increasing CO2 emissions into the atmosphere only theoretically.