Carbon mineralization is currently one of the most direct ways we can remove carbon dioxide (CO₂) from our atmosphere. In the scope of carbon offsets, mineralization could play a crucial role in reducing atmospheric CO₂ levels. So, we had to ask: What are carbon mineralization offsets really, and could they help us mitigate climate change?

Carbon mineralization offsets are a specific type of carbon offset that remove carbon from the atmosphere. CO₂ is either pumped into underground rock formations or exposed to certain rocks at the surface, where it is stored permanently in mineral form via a chemical reaction.

Keep reading to find out all about what carbon mineralization offsets are, how they work, what their project life-cycle is, how effective they are, their pros and cons, and how they can help mitigate climate change. 

The Big Picture of Carbon Mineralization Offsets

Carbon offsets are reductions in carbon emissions that are used to compensate for carbon emissions occurring elsewhere. They are measured in tons of carbon dioxide (CO₂) equivalents and are bought and sold through international brokers, online retailers, and trading platforms on what is known as the global carbon offset market. 

“Carbon Offset: a way for a company or person to reduce the level of carbon dioxide for which they are responsible by paying money to a company that works to reduce the total amount produced in the world, for example by reforestation”

Oxford Dictionary

Carbon mineralization is a form of technological carbon removal whereby atmospheric CO₂ reacts with silicate material and rocks rich in calcium and magnesium (e.g., basalt rocks) to permanently lock away CO₂ for thousands of years.

“Carbon mineralization: the process by which carbon dioxide becomes a solid mineral, such as a carbonate. It is a chemical reaction that happens when certain rocks are exposed to carbon dioxide”

The United States Geological Survey 

For underground mineralization, CO₂ is injected into wells that lead to igneous or metamorphic rock formations. For mineralization at the surface, CO₂ is exposed to basalt rocks, ultramafic rocks, or mine tailings (mine waste).

What Are Carbon Mineralization Offsets

Carbon offsets are reductions in GHG emissions that are used to compensate for emissions occurring elsewhere. They are measured in tons of CO₂ equivalents and are bought and sold through international brokers, online retailers, and trading platforms.

Carbon mineralization offsets involve the process by which atmospheric CO₂ reacts with silicate material and rocks rich in calcium and magnesium (e.g., basalt rocks) to form solid minerals.

How Are Carbon Offsets Defined

Carbon offsets play a crucial role in reducing our carbon footprint, the amount of CO₂ emissions associated with an individual or an entity. 

“Carbon footprint: the amount of greenhouse gasses and specifically carbon dioxide emitted by something (such as a person’s activities or a product’s manufacture and transport) during a given period”

Merriam Webster

Basically, a carbon footprint is the amount of carbon emitted by an activity or an organization. This includes GHG emissions from fuel that we burn directly (e.g., heating a home, driving a car) and GHG emissions from manufacturing the products that we use (e.g., power plants, factories, and landfills). 

One way to reduce our carbon footprint is via the use of carbon offsets. These are mineralizations in GHG emissions that are measured in tons of CO₂ equivalents and are bought and sold through international brokers, online retailers, and trading platforms. 

“Carbon offset: a way for a company or person to reduce the level of carbon dioxide for which they are responsible by paying money to a company that works to reduce the total amount produced in the world, for example by planting trees”

Oxford Dictionary

When you hear the words “carbon offset”, think about the term “compensation”. Essentially, carbon offsets are mineralizations in GHG emissions that are used to compensate for emissions occurring elsewhere. Carbon offsets can range anywhere from a couple of hundred tons of CO₂ per program per year to thousands of tons of CO₂ per program per year. 

How Are Carbon Mineralization Offsets Defined

Carbon mineralization is a form of technological carbon removal, the process of eliminating carbon from the atmosphere. More specifically, it is the removal of carbon from the atmosphere by sequestering it in permanent reservoirs.

“Carbon Removal: the process of removing CO₂ from the atmosphere”

The Intergovernmental Panel on Climate Change

Carbon mineralization, also referred to as enhanced weathering, refers to the process by which atmospheric CO₂ reacts with silicate material and rocks rich in calcium and magnesium (e.g., basalt rocks).

“Carbon mineralization: the process by which carbon dioxide becomes a solid mineral, such as a carbonate. It is a chemical reaction that happens when certain rocks are exposed to carbon dioxide”

The United States Geological Survey 

Carbon can be mineralized either by injecting CO₂ into underground rock formations or exposing CO₂ to broken pieces of rock at the Earth’s surface. Both approaches permanently lock away atmospheric carbon for thousands of years.

How Do Carbon Mineralization Offsets Work

Carbon mineralization includes approaches that aim to speed up the naturally occurring weathering process whereby atmospheric CO₂ chemically reacts with certain types of rocks to form a solid mineral. 

When certain rocks (e.g., basalt, ultramafic, mine tailings) are exposed to CO₂, it triggers a chemical reaction that forms new carbonate material in the rocks. This locks away CO₂ permanently with a limited possibility of re-emission, even if the rocks are broken.

How and When Do Carbon Mineralization Offsets Reduce Your Carbon Footprint

Carbon mineralization refers to the direct elimination of carbon from our atmosphere via its storage in geologic reservoirs. It is one way to mitigate the adverse effects of CO₂ emissions that occur once they enter our atmosphere.

How Do Carbon Mineralization Offsets Reduce Your Carbon Footprint

Carbon mineralization projects reduce CO₂ emissions by exposing certain rocks to CO₂, which then converts the CO₂ into solid minerals. 

There are two main types of carbon mineralization:

• Injecting CO₂ into underground rock formations
• Exposing CO₂ to broken pieces of rock at the Earth’s surface

Underground, CO₂ is injected into wells that lead to igneous or metamorphic rock formations. At the surface, CO₂ is exposed to basalt rocks, ultramafic rocks, or mine tailings (mine waste). Both approaches permanently lock away atmospheric carbon for thousands of years.

When Do Carbon Mineralization Offsets Reduce Your Carbon Footprint

Carbon mineralization is a natural process that occurs over millions of years. Carbon mineralization projects aim to speed up this process by breaking down silicate rocks into tiny pieces, thereby skipping slow weathering processes.

For example, Carbfix achieves 95% permanent carbon mineralization in under two years. And in comparison, newly planted trees for reforestation offsets could take upwards of 20 years to capture the amount of CO₂ that most carbon offset programs promise. 

When comparing this to other methods of carbon removal like planting trees, we find that carbon mineralization reduces CO₂ emissions faster and more permanently. 

• For example, a newly planted tree could take upwards of 20 years to capture the amount of CO₂ that most carbon offset programs promise. 
• Also, there is always the risk of, e.g., droughts, wildfires, tree diseases, and deforestation wiping out newly planted trees, negating any carbon reduction benefits. 

What Could Prevent Carbon Mineralization Offsets From Being Realized

Carbon mineralization offsets are one of the most expensive methods of carbon removal, are not yet scaled to compensate for our global emissions, and do not reduce your own emissions, which can lead to greenwashing.

Behind direct carbon capture (DCC), carbon mineralization offsets are one of the most expensive offsets out of all of the carbon removal methods. Mineralization offsets currently range anywhere from $82 – $1,200 per ton of CO₂, depending on the type of technology, type of energy source, and scale of the operation. In comparison, reforestation offsets cost approximately $50 per ton. 

Carbon mineralization offsets are also not yet scaled enough to keep pace with our global carbon emissions. Because there are relatively few companies engaged in carbon mineralization on a commercial level, the amount of carbon they can sequester is limited.

Lastly, purchasing a carbon offset does not directly reduce your carbon footprint. It only makes others reduce their carbon footprint to compensate for your carbon footprint. 

If emissions are only offset and not reduced from the source, this could lead to greenwashing, when the consumer is deceived into thinking they are offsetting their emissions but in reality, they are not.

What Is the Project Life-Cycle of Carbon Mineralization Offsets

To fully understand carbon mineralization offsets, we must assess each stage of its life cycle. This life-cycle assessment (LCA) is a method to evaluate the environmental impacts of products and materials. Over the years, companies have strategically used LCA to research and create more sustainable products. So, we had a look at the LCA for carbon mineralization offsets! 

Building of Carbon Mineralization Offsets

The building of carbon mineralization offsets includes building mineralization powerplants, identifying lands for injection or above-ground exposure, and actually injecting CO₂ or spreading crushed rocks.

Carbon mineralization plants for CO₂ injection are most effective in locations where there is excess renewable energy available along with ample natural storage options for the CO₂. 

For example, the greatest potential for mineralization underground and at the surface in the US is in the pacific northwest, specifically Idaho, Oregon, and Washington. Some East and West Coast states also have the potential for mineralization via mine tailings. 

Iceland is also a hotspot for mineralization due to ample geothermal energy coupled with large underground basalt rock formations. Carbfix’s Hellisheiði Powerplant is a prime example of this. 

Operating and Maintaining of Carbon Mineralization Offsets

There are very few CO₂ emissions or waste products associated with operating and maintaining carbon mineralization projects, making the carbon footprint of this phase low.

In general, there is no long-term monitoring or maintenance required for carbon mineralization projects after the chemical reaction between the rocks and CO₂ is initiated. CO₂ emissions at this stage are associated with the operation and maintenance of the carbon mineralization plants.

Although carbon mineralization facilities that inject CO₂ underground require energy to operate, they can re-emit only small amounts of CO₂ if powered by low-carbon energy sources. For example, Carbfix’s Hellisheiði Powerplant runs on geothermal energy, which emits 38 grams of CO₂ equivalent per kWh of electricity produced. Compare this to coal power plants, which emit 820 grams of CO₂ equivalent per kWh of electricity produced.

Also, injecting CO₂ underground can require large amounts of water. Water usage will depend on the type of plant, as well as local temperature and humidity. Carbfix addresses this concern by sourcing its water from the reservoir in which injection occurs so that it can be circulated and reused.

Lastly, the operating/maintaining stage is also where the offsetting promised by mineralization projects occurs. When CO₂ reacts with basalt rocks, ultramafic rocks, or mine tailings, the chemical reaction that follows converts CO₂ into carbonate, permanently removing it from the surrounding air.

End-of-Life of Carbon Mineralization Offsets

The end-of-life of energy-efficiency offsets would include the end-of-life of the technology or anything that negates the project’s effectiveness.

The end-of-life of carbon mineralization offset projects is not yet well documented because mineralization itself is a relatively new technology. But we do know that rates of carbon re-emission are very low given that mineralization is a permanent process.

For example, greenSand Olivine rocks permanently store carbon and will only release that carbon back into the atmosphere if the temperature exceeds 1,600 degrees. In addition, even if the rocks are broken, the carbon will remain trapped inside. This makes mineralization effective at reducing CO₂ emissions.

Carbfix: An Example Project of Carbon Mineralization Offsets

Since 2017, Carbfix has been working with Climeworks, a direct air capture company based in Zurich, Switzerland. After Climeworks’ specialized machines directly capture CO₂ from the air, Carbfix then turns the captured CO₂ into stone in less than two years. 

Carbfix first dissolves the captured CO₂ in water to create a slurry, before injecting it underground where it reacts with basalts and other reactive rock formations to form solid minerals (carbonates) via natural processes. These carbonates remain stable for thousands of years, making the process permanent. To date, Carbfix has injected over 70,000 tons of CO₂ at their Icelandic site.

How Effective and Efficient Are Carbon Mineralization Offsets

In terms of effectiveness, carbon mineralization offsets permanently and quickly remove CO₂ from the atmosphere; however, they do not reduce your own carbon emissions, which can lead to greenwashing.

In terms of efficiency, carbon mineralization offsets have low rates of carbon re-emission; however, they are also relatively expensive and are not yet scaled to compensate for our global emissions.

Carbon mineralization offsets are effective at mitigating climate change because they:

• Permanently lock away CO₂ for thousands of years with no long-term monitoring required
• Reduce emissions quicker than natural weathering processes and other nature-based solutions

However, carbon mineralization offsets can also lack effectiveness because they do not reduce your own carbon emissions, which can lead to greenwashing. This occurs when emissions are only offset and not reduced from the source, and the consumer is deceived into thinking they are offsetting their emissions but in reality, they are not.

Carbon mineralization offsets are efficient at reducing CO₂ emissions because they are a permanent process that has very low rates of CO₂ re-emission. In addition, even if the rocks are broken, the carbon will remain trapped inside. 

However, carbon mineralization offsets can also lack efficiency because they are one of the most expensive offsets out of all of the carbon removal methods, behind direct carbon capture (DCC). They are also not yet scaled to compensate for our global carbon emissions, although they could be scaled up to capture 2-4 billion tons of CO₂ per year by 2050.

How Could You Offset Your Own Carbon Footprint With Carbon Mineralization Offsets

The market for carbon offsets was small in the year 2000, but by 2010 it had already grown to represent nearly $10 billion worldwide. The voluntary carbon offset market (VCM) is where everyday consumers can purchase carbon offsets to offset their carbon emissions, and the Ecosystem Marketplace predicts the VCM can grow to $50B by the year 2050. 

Carbon mineralization takes advantage of natural chemical processes and can permanently and quickly remove carbon from the atmosphere, locking it away for thousands of years. Because it has the potential to store large amounts of carbon, it is predicted to make up an increasing share of the VCM. Below are our favorite carbon mineralization offsets.

How Can Carbon Mineralization Offsets Help Mitigate Climate Change

Climate change is a severe and long-term consequence of fossil fuel combustion. Carbon mineralization offsets can help mitigate climate change because they permanently eliminate fossil-fuel-derived carbon from our atmosphere which, if left untreated, can remain there for tens of thousands of years and exacerbate the negative effects of climate change.

How Is Climate Change Defined

Climate change is arguably the most severe, long-term global impact of fossil fuel combustion. Every year, approximately 33 billion tons (bt) of CO₂ are emitted from burning fossil fuels. The carbon found in fossil fuels reacts with oxygen in the air to produce CO₂. 

“Climate change: changes in the earth’s weather, including changes in temperature, wind patterns and rainfall, especially the increase in the temperature of the earth’s atmosphere that is caused by the increase of particular gasses, especially carbon dioxide.”

Oxford Dictionary

Atmospheric CO₂ fuels climate change, which results in global warming. When CO₂ and other air pollutants absorb sunlight and solar radiation in the atmosphere, it traps the heat and acts as an insulator for the planet. Since the Industrial Revolution, Earth’s temperature has risen a little more than 1 degree Celsius (C), or 2 degrees Fahrenheit (F). Between 1880-1980 the global temperature rose by 0.07C every 10 years. This rate has more than doubled since 1981, with a current global annual temperature rise of 0.18C, or 0.32F, for every 10 years. 

As outlined in the 2015 Paris Climate Agreement, we must cut current GHG emissions by 50% by 2030 and reach net zero by 2050. 

How Do Carbon Offsets Generally Help Mitigate Climate Change

Levels of carbon in our atmosphere that cause climate change have increased as a result of human emissions since the beginning of the Industrial Revolution in 1750. The global average concentration of carbon dioxide in the atmosphere today registers at over 400 parts per million. Carbon offsets can help prevent these levels from increasing even more.

When you hear the words “carbon offset”, think about the term “compensation”. Essentially, carbon offsets are reductions in GHG emissions that are used to compensate for emissions occurring elsewhere. 

Carbon offsets that meet key criteria and verified project standards, are additional and permanent, and are part of projects that are carried out until the end of their lifespan have the best chance of reducing carbon emissions and therefore reducing climate change. 

When we offset CO₂ we also slow the rate of global temperature rise, which in turn minimizes the effects of climate change. 

How Do Carbon Mineralization Offsets Specifically Help Mitigate Climate Change

Carbon mineralization can specifically help mitigate climate change because it eliminates atmospheric carbon, which when emitted, can remain in our atmosphere for a long period of time. Whether via underground injection, concrete, or mine tailings, the process of carbon mineralization permanently locks away CO₂ for thousands of years.

What Are The 5 Pros and 4 Cons of Carbon Mineralization Offsets

Carbon mineralization offsets are permanent, have a low rate of carbon re-emission, reduce emissions quickly, protect the biosphere, and can help offset emissions that cannot be reduced otherwise. 

Carbon mineralization offsets are one of the most expensive methods of carbon removal, are not yet scaled to compensate for our global emissions, may induce seismic activity, and do not reduce your own emissions, which can lead to greenwashing.

What Are the 5 Pros of Carbon Mineralization Offsets

Carbon mineralization offsets have various pros that make them effective at sequestering carbon from our atmosphere.

What Are the 4 Cons of Carbon Mineralization Offsets

Understanding the drawbacks of carbon mineralization offsets is important when implementing this strategy on a large scale in order to mitigate climate change.

What Are Better Alternatives to Carbon Mineralization Offsets

If used correctly, carbon mineralization offsets can provide environmental, economic, and social benefits beyond reducing carbon emissions. They have the potential to instigate meaningful environmental change and begin to reverse some of the effects of climate change. 

However, we can’t let this method be a guilt-free way to reduce carbon emissions. Carbon mineralization offsets must be used in conjunction with direct carbon reduction measures until the industry has time to develop, refine, and make the technology more affordable.

These reduction measures don’t have to involve drastic changes either. Actions that may seem minor can have a significant impact because those small changes add up! You can reduce your carbon footprint in three main areas of your life: household, travel, and lifestyle. 

Reduce your household carbon footprint:

• Wash with cold water: Washing clothes in cold water could reduce carbon emissions by up to 11 million tons. Approximately 90% of the energy is used to heat the water, so switching to cold saves also saves energy.

• Replace incandescent bulbs with fluorescent bulbs: Fluorescent bulbs use 75% less energy than incandescent ones, saving energy and thus reducing electricity demand and GHG emissions.

Reduce your travel carbon footprint:

• Fly less: Aviation accounts for around 1.9% of global carbon emissions and 2.5% of CO₂. Air crafts run on jet gasoline, which is converted to CO₂ when burned.

• Walk or bike when possible: The most efficient ways of traveling are walking, bicycling, or taking the train. Using a bike instead of a car can reduce carbon emissions by 75%. These forms of transportation also provide lower levels of air pollution.

Reduce your lifestyle carbon footprint:

• Switch to renewable energy sources: The six most common types of renewable energy are solar, wind, hydro, tidal, geothermal, and biomass energy. They are a substitute for fossil fuels that can reduce the effects of global warming by limiting global carbon emissions and other pollutants.

• Recycle: Recycling uses less energy and deposits less waste in landfills. Less manufacturing and transportation energy costs means fewer carbon emissions generated. Less waste in landfills means less CH₄ is generated.

• Switch from single-use to sustainable products: Reusing products avoids resource extraction, reduces energy use, reduces waste generation, and can prevent littering.

• Eat less meat and dairy: Meat and dairy account for 14.5% of global GHG emissions, with beef and lamb being the most carbon-intensive. Globally, we consume much more meat than is considered sustainable, and switching to a vegan or vegetarian diet could reduce emissions. 

• Take shorter showers: Approximately 1.2 trillion gallons of water are used each year in the United States just for showering purposes, and showering takes up about 17% of residential water usage. The amount of water consumed and the energy cost of that consumption are directly related. The less water we use the less energy we use. And the less energy we use, the less of a negative impact we have on the environment.

Because carbon mineralization offsets are an indirect way and not a direct way of reducing emissions, they alone will not be enough to reduce global carbon emissions significantly. Direct measures of emission reductions, such as reducing individual energy use and consumption, are better alternatives to carbon mineralization offsets. 

Final Thoughts

Carbon mineralization offsets are a specific type of carbon offset that remove carbon from the atmosphere. CO₂ is either pumped into underground rock formations or exposed to certain rocks at the surface, where it is stored permanently in mineral form via a chemical reaction. CO₂ reduction occurs quickly, making mineralization an effective and efficient way to reduce CO₂ emissions. 

Although carbon mineralization offsets can instigate meaningful change, they should not be seen as the only solution to climate change. They are effective at reducing CO₂ in the short-term, but in the long term they fail to reduce CO₂ enough. Offsets, in general, also do not reduce your own carbon emissions, which can lead to greenwashing.

When used in conjunction with direct CO₂ reduction measures, carbon offsetting can be much more effective. We should reduce our own carbon footprint as much as possible first, and only then choose the most effective carbon mineralization offsets.

Stay impactful,

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