What is Enhanced Rock Weathering?


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Understanding Enhanced Rock Weathering for Carbon Dioxide Removal

Did you know that rocks can remove carbon dioxide from the atmosphere? While most people know that trees have the ability to naturally purify the air, rocks also play a vital role in balancing the carbon cycle that sustains Earth’s delicate ecosystem.

Enhanced Rock Weathering (ERW) is an emerging carbon dioxide removal technique with immense potential. But how exactly do rocks remove carbon dioxide, and what’s the science behind it? Exploring these questions can offer new perspectives and spark hope for a better future.

Join us as we share how InPlanet is pioneering the acceleration of this natural process. By harnessing the power of Enhanced Rock Weathering, we are creating a more sustainable world for us and for future generations.

What is weathering?

To understand what Enhanced Rock Weathering is, we firstly need to understand what weathering is. Weathering is nature’s way of breaking down rocks over time. It is driven by natural processes such as rain, wind, heat, and biological activity.

Imagine a big rock sitting outside in your garden. Over the years, wind, rain, sunlight, and microorganisms start to wear it down. The rock might crack, crumble, or even turn into smaller pieces. This process changes the rock’s appearance and texture, and eventually, if you wait for thousands of years, the rock will become part of the soil. That’s weathering! Nature’s slow but steady way of sculpting the earth’s surface.

Now, expand your imagination to think outside your garden and envision you are on holiday admiring the beautiful rock formations by the beach. The rocks you see were shaped by two weathering processes

Mechanical weathering involves forces like the wind or waves slowly breaking down small pieces of these rocks. 

Chemical weathering occurs when rocks react with substances like water and acids, changing their composition. Here is the awe factor! There’s a natural chemical process that allows rocks to remove carbon dioxide.

Let’s dive into science

Enter the fascinating world of chemistry with us as we explore how rocks interact with carbon dioxide, effectively removing it from the atmosphere. To understand the complexities of this natural process, let us trace the path of carbon from the atmosphere down into the Earth’s depths.

Why is rain acidic?

Carbon Dioxide (CO2) is a molecule present in the atmosphere, alongside other gases like Oxygen and Nitrogen. When it rains, this CO2 is dissolved in raindrops (H2O), forming a weak acid, carbonic acid (H2CO3). This naturally occurring acid is the main reason why rain is always acidic.

Rain meets rocks 

As the CO2 in the rain reaches land…, it comes in contact with rocks. Rocks are composed of minerals that contain elements such as Calcium and Magnesium. Carbonic Acid (formed by H2O + CO2) slowly reacts with these minerals present in the rocks to form bicarbonate. Here is where the magic happens! Once carbon is transformed into bicarbonate, it stays in the soil and does not return to the atmosphere.

Bicarbonate is something we all may have in our kitchen in the form of baking soda. The one you may have at home is sodium bicarbonate, and it is what will make your muffins soft and fluffy. On the ground, though, we may have bicarbonates of the different minerals from the rock (such as Calcium and Magnesium). 

Carbon’s journey to the sea

Bicarbonates, besides being harmless to humans, can bring numerous benefits to the environment. Because this molecule is soluble in water, the rain will carry bicarbonates from the rocks into the soil, then through the rivers, and finally into the sea, where they will help combat ocean acidification (another problem caused by climate change) and store carbon for thousands of years.

Speeding up nature

“Rock Weathering is probably the oldest carbon dioxide removal technology. It’s been removing and storing CO2 for millions of years and has helped keep the planet habitable for us and other life.”

Dr. Christina Larkin, InPlanet’s Head of Science

Enhanced Rock Weathering accelerates this natural process, speeding up carbon dioxide removal so that we can fight climate change at the fastest pace we need. To do that, we use finely ground rocks, what we call rock powder, and spread them over agricultural land.

Rock powder reacts with acid rain to absorb carbon dioxide the same way a large rock would, just a lot faster. The natural process, which would normally take thousands of years to occur, can now happen in less than a decade.

But how is it possible to make this happen so much faster?

Imagine you have a cup of water and want to add sugar to it. You have the option to add a sugar cube or granulated sugar. Which one would dissolve faster? Granulated sugar dissolves a lot faster because it has a higher surface area. The more surface area, meaning the finer the sugar, the faster it will dissolve. The same is true for rock powder.

While a boulder would take thousands of years to ‘dissolve,’ when we grind rocks into a fine powder and spread it directly on the soil, the chemical reaction happens much faster.

“It is a natural process, and instead of happening over hundreds of thousands to millions of years, we speed it up to happen in less than a decade. And we do this by taking rock from the earth, crushing it, grinding it to small particle size, and then spreading it on farmland, where this process will happen much more quickly.”

Dr. Christina Larkin, InPlanet’s Head of Science
Tractor with plants in the foreground. Man driving tractor

A better future is possible

Enhanced Rock Weathering reshapes our perspectives on the future, bringing up hope for a natural reversal of climate change’s impacts.

What makes Enhanced Rock Weathering particularly promising is its ease of implementation, as it requires no additional land or infrastructure. We’re helping the planet cleanse itself the way it always did, just faster.

By harnessing the power of rocks, we are paving the way for a more sustainable and resilient future for generations to come. It’s time to embrace this innovative approach and work together towards a healthier planet for all of us. Reach out to us to discover how you can play a vital role in this inspiring movement.