Sinking carbon dioxide: with rock dust against global warming – Wikipedia

carbon dioxide (CO2) high. From energy production alone, 36.3 billion tons were released worldwide in 2021. Much to slow global warming. Most of all are ways to reduce carbon dioxide2 to remove it from the atmosphere. One drives across the seas: Water can absorb greenhouse gases, and dissolve in them. Absorption increases when certain minerals dissolve in the sea and the chemical environment changes.

Something similar has happened on Earth since ancient times with the weathering of rocks, but very slowly. The researchers now want to speed up the carbon dioxide uptake in seawater. However, it is doubtful how effective the procedures are and whether there are drawbacks.

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Large pilot ships of world scale

This should show tests in Raunefjord, south of Bergen in Norway, which will run until mid-July. Scientists brought the intermediate planets to the water there: large plastic tubes, two meters in diameter and 20 meters deep, suspended in the strait like giant test tubes.

Herring larvae were placed in the Mesozoic of the Ronfjord River natural community to follow their evolution in a climate experiment. The team adds slaked lime, a representative of calcium-based minerals, and magnesium silicate, a representative of siliceous minerals. “We’re going to work with different amounts and note the changes associated with this for habitat and how effective the method is at absorbing carbon dioxide,” says research director Ulf Riebesell of the Geomar Helmholtz Center for Ocean Research in Kiel.

According to the scientist, model calculations confirmed that this process has a huge potential to protect the global climate. But it was calculated by increasing the pH value at the area level. “In fact, the metals are introduced selectively, so you have to look closely.” For example, ground basalt or limestone can lose water or sink quickly – water near the surface, which is critical for absorbing carbon dioxide from the air, will remain unchanged and there will be no effect.

Even if rock flour, which is currently a favorite in research and potential industrial applications, is dissolved, the solution may very quickly disappear underground. Or the water can become supersaturated. Then carbonates and carbon dioxide precipitate2 become free again. Water temperature and natural carbonate content also greatly influence how much gas is absorbed.

Research diver working on one of the intermediate worlds in Raunefjord in Norway.Photo: Michael Swat / GEOMAR

The difficulties lie not only in the biology and chemistry of seawater. It’s also not clear where the massive amounts of rock are supposed to come from. Hardly any contributions can be expected, at least from Germany, as every quarry expansion is disputed. This differs in other countries, especially since materials from the cement industry are also seen as potentially acidic solutions.

Whether they are allowed in the water is another question. Trials are taking place in Norway for a reason. “In Germany, you’re not even allowed to put loads of homeopathic in seawater for research purposes,” Ripzel says. Legal requirements must be established for use with large volumes of ground rock or concrete.

“Governance will require at least some amount of work, such as laying the scientific foundations,” says the researcher. There is still a lot to explain: In addition to the immediate effects, scientists are interested in whether CO2The recording is really long-term and will not be undone by other processes. “It is also unclear how the monitoring will take place,” says the marine researcher. Like a company that pays CO2 for your performance2The credits, she could prove she really contributed. “Changes in alkalinity in the water after application are very small and likely masked by natural contrast.”

Business Model “Negative Emissions”

Many startups are active in this field. Ebb Carbon, for example, would like to use green electricity to extract hydrochloric acid from seawater for industrial processes and return the remaining caustic soda to correct the pH. Instead, Planetary Technologies wants to treat mining wastewater and discharge it into the sea to isolate the acid. SeaChange, in turn, wants CO2 From the sea to extract industrial limestone and magnesite for the construction industry. According to, these three companies have already sold climate compensation vouchers to internet companies such as Shopify and Stripe.

This shows how quickly the new market is developing here. “I worry that academic research will not be able to keep pace with this dynamic,” says Repsil. The pressure from the private sector is so great that individual measures have already been approved in some areas, although it is not yet clear whether they will actually achieve anything.

Other experts are also concerned. In December, the US National Academy of Sciences recommended research on carbon dioxide in the oceans2Enhancement of the withdrawal by 125 million dollars. “If we are going to make informed decisions about the future of our oceans and our climate, we need to complete some very important research over the next decade,” says Scott Donny of the University of Virginia.

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