The United Nations has deemed carbon removal “essential” if the world is to meet its goals of achieving net-zero greenhouse gas emissions. According to the UN and other climate change organizations, eliminating emissions will not be sufficient; we must also remove existing carbon from the atmosphere.
Many promising carbon removal technologies have emerged recently, including enhanced rock weathering (ERW). This innovative method amplifies a natural geological phenomenon wherein carbonic acid rainfall engages with rocks and soil, effectively sequestering carbon in natural geological formations.
Let’s look at how enhanced rock weathering works, its potential to mitigate climate change, and potential hurdles in its implementation.
Why Is Carbon Removal So Important?
Carbon removal is crucial in tackling climate change because it addresses the excess carbon dioxide (CO2) in the Earth’s atmosphere. Elevated CO2 levels result from human activities like burning fossil fuels and deforestation, which contribute to global warming. Removing carbon dioxide helps mitigate its impact by curbing rising temperatures, reducing ocean acidification, and diminishing the severity of extreme weather events.
Beyond merely reducing emissions, carbon removal actively reverses the damage already done. It offers a way to achieve net-zero emissions and even aim for negative emissions, where more CO2 is removed than emitted. This process is crucial in meeting the climate targets outlined in international agreements like the Paris Accord and preventing catastrophic climate effects in the future.
Carbon removal methods, including natural solutions like afforestation and technological approaches like direct air capture or enhanced rock weathering, are pivotal in transitioning to a sustainable future. They complement emissions-reduction strategies and offer hope for mitigating the effects of climate change and ensuring a habitable planet for future generations.
How Does Enhanced Rock Weathering Work?
Enhanced rock weathering is a process that involves accelerating the natural process of CO2 removal by spreading finely crushed silicate rocks, such as basalt, on the Earth’s surface.
When exposed to weathering, these rocks chemically react with CO2 in the atmosphere, converting it into bicarbonate ions. These ions are then washed away by rainwater and rivers, eventually reaching the oceans where they contribute to the formation of stable carbonate materials, effectively locking away the carbon for hundreds of thousands of years.
The rock weathering process has been naturally occurring for millions of years. In the natural environment, carbon dioxide combines with rainwater, forming carbonic acid. This acid precipitates to the Earth’s surface, where CO2 interacts with rocks and soil, undergoing mineralization and being stored as carbonate. ERW is an expedited version of this natural process, achieving in decades what typically takes hundreds of thousands of years.
What Are the Benefits of Enhanced Rock Weathering?
ERW offers a promising solution in the fight against climate change. One significant advantage is its potential scalability. It utilizes naturally occurring materials, does not require arable land, and does not compete with agriculture. It also offers long-term carbon storage, as the captured carbon becomes a permanent part of rocks and soils.
Additionally, this carbon removal method does not rely on energy-intensive processes and can be deployed globally to help reach carbon removal targets. It’s a cost-effective, environmentally friendly solution that complements other carbon removal strategies.
ERW also offers numerous co-benefits that are not directly related to carbon removal or storage. Basalt and other silicate rocks are rich in minerals and enhance soils when spread across agricultural areas. This can reverse soil acidification and reduce the need for greenhouse gas-emitting fertilizers like nitrogen oxide. Topsoil deterioration is a significant challenge for the modern agricultural sector and international food security, but ERW can potentially increase crop yields by up to 40 percent.
This technology can also help de-acidify our oceans, which have become more acidic due to excess CO2 in the atmosphere. The ERW process generates bicarbonate ions, which are washed into the oceans and contribute to their de-acidification. Crustaceans like mussels and lobsters can use the calcium carbonate produced during this process to build shells, which then fall to the floor of the ocean and form limestone and other carbonate rocks that can store CO2 for millions of years.
Hurdles in the Implementation of Enhanced Rock Weathering
Although ERW has enormous potential, there are also several challenges in its implementation on a global scale. The logistics of transporting substantial rock quantities pose a hurdle due to energy-intensive operations and potential emissions. Public perception also plays a role; educating and transparently communicating the process is crucial for public acceptance.
ERW implementation will also require major infrastructure projects, which will require major investments from companies, individual investors, and governments. Securing funding remains a challenge for natural carbon capture methods like ERW, as there are limited financial incentives currently. Nonetheless, the evolving landscape of carbon markets and policies could potentially unveil new investment opportunities.
However, these challenges could also present opportunities. Investing in ERW can align with other climate solutions, especially as policies evolve to support such endeavors. Despite these hurdles, ongoing research offers reason to be optimistic about improved materials and techniques, making ERW a potentially game-changing climate tool with environmental and financial benefits.