Geoengineering could destabilize tropical peat soils

The earth is warming up faster and faster. One contributing factor is carbon dioxide (CO₂), a greenhouse gas that prompted researchers to investigate methods to reduce concentrations. dr In her dissertation at the University of Bremen, Alexandra Klemme found out that the “enhanced weathering” strategy, which has so far been considered promising, is not suitable for CO removal₂ from tropical peat soils. The research results are now published in Communication Earth & Environment.

“Various strategies for capturing carbon dioxide (CO₂) from the atmosphere are discussed worldwide. One of these methods is enhanced weathering,” explains Dr. Alexandra Klemme. As part of her doctoral thesis, she examined the effects of increased weathering on tropical peat soils and concluded that this approach is not suitable for reducing CO₂ in these areas.

dr Klemme researched at the Institute for Environmental Physics at the University of Bremen (Dr. Thorsten Warneke, Professor Justus Notholt) in close cooperation with the Bremen Leibniz Center for Tropical Marine Research (Dr. Tim Rixen) and Swinburne University in Malaysia (Dr. Moritz Müller).

Why “enhanced weathering” and why tropical peat soils?

Weathering is a natural process in which a chemical reaction binds CO₂ with rock and water, removing it from the atmosphere. “This is happening extremely slowly, and a reduction in atmospheric CO₂ You only notice that when you look at the trend over thousands of years,” says Dr. clamp. The advanced weathering method involves crushing rocks into powder. “This increases the surface area on which the chemical reaction takes place, which accelerates the weathering process. The application of rock flour to land – for example agricultural land – is being discussed as a possible method for reducing atmospheric CO₂.”

Warm and humid conditions further accelerate the weathering process, making tropical bogs one of the potential targets for enhanced weathering. About half of these bogs are in Southeast Asia. They store huge amounts of carbon and absorb CO in their natural state₂ from the atmosphere. Today, much of these bogs have been converted to farmland.

“In most cases this is associated with drainage and results in bogs being converted from CO₂ sinks in CO₂ sources,” explains Dr. clamp. This CO should be counteracted by increased weathering in these regions₂ Sources. “In addition, increased weathering would increase the pH value in the acidic soils. The agribusiness would appreciate this because it increases crop growth.”

Elevated pH levels destabilize peat soils

However, this approach will not have the desired effect, since an increase in pH due to increased weathering would destabilize the peat soil. Beyond increasing CO₂ Emissions from peat soils were discovered by Dr. Klemme that this technique resulted in more carbon being leached into rivers, thus increasing CO₂ Emissions from rivers and coastal areas.

The research was based on measurements of peat-draining river courses in Indonesia and Malaysia. The measurements were carried out over the past ten years by the Institute for Environmental Physics, the Leibniz Center for Tropical Marine Research and Swinburne University. The study shows that increased pH could lead to total CO₂ -Emissions above expected CO2 emissions₂ Photo due to increased weathering. “Therefore, this method is ruled out,” says Dr. clamp.

Provided by the University of Bremen