Fun fact: – Nature already sequesters carbon this way, but it takes millions of years. We can significantly accelerate this process...

Speed of impact: 5-20 years

Potential to scale: Large

Permanence: 100,000 years +

Additional benefits: Enhanced rock weathering helps improve soil quality on agricultural land, increasing crop yields.

What is Rock Weathering?

When it rains, carbon dioxide in our atmosphere mixes with rainwater to form a weak carbonic acid.

When this dilute acid falls on exposed rocks and soils, it reacts with them, forming solid carbonates that safely lock the carbon away for hundreds of thousands of years.

Which is great! Unfortunately, it’s a very slow way of locking carbon away.

What is Enhanced Rock Weathering?

Enhanced rock weathering involves taking rocks that naturally absorb carbon from our atmosphere, grinding them into a fine powder, and spreading them on fields. The grinding and spreading increase the surface area of the rocks, exposing them to more rain and, therefore, more carbon dioxide, which accelerates the carbon absorption process.

The rocks used in this process are naturally rich in minerals. As they weather on the ground, they release these minerals and enrich the soil. When spread on agricultural land, this improved soil quality can lead to increased crop yields. Bonus!

Where Does the Rock Come From?

There are a range of different types of rock that are used in enhanced rock weathering: basalt and wollastonite being two examples.

In the UK, basalt fines (powdered basalt) are an aggregate produced by quarries.

In Canada, wollastonite is mined specifically for use in enhanced rock weathering.

Suppliers of enhanced rock weathering measure the carbon footprint of their end-to-end operations, including the impact of mining or quarrying for the rock. This is carefully accounted for when calculating the overall carbon efficiency of the technique.

For example; a supplier who uses wollastonite achieves a 90% efficiency rate. And reports a 95% efficiency rate when using basalt in the UK.

Where is the Rock Spread?

The powdered rocks used in enhanced rock weathering are spread on agricultural fields.

The sites are carefully monitored before, during, and after spreading the rock to ensure the impact is measurable and that no unforeseen consequences arise from the process.

Why Do We Like Enhanced Rock Weathering at Glad?

At Glad, we believe that speed is of the essence when it comes to removing excess greenhouse gases from our atmosphere. The faster we remove each tonne of carbon, the less it will contribute to the heating of our planet.

We like enhanced rock weathering, particularly the wollastonite version, which can sequester one tonne of carbon in just five years, because it is an accelerated natural process that locks carbon away for an exceptionally long time.

The fact that it also improves soil quality on agricultural land and can help increase crop yields is an added bonus.