The idea of geoengineering, or juggling our planet’s climate systems to slow warming, is often discussed for experiments that could eventually be conducted in the air. We talk less about water, where however the direct impact on life would be immediate.
In this case, a team from the Georgia Institute of Technology in Atlanta became interested in the idea of making the water more alkaline, thereby raising its pH, which would increase its ability to absorb the carbon we are transporting into the atmosphere. Based on this idea, the researchers attempted to estimate what effects more alkaline waters would have on the marine food chain.
The estimate is not encouraging, summarizes biogeochemist Chris Reinhard in New Scientist. The tons of minerals that would have to be dumped to impair the oceans’ ability to absorb more carbon would reduce accessibility to the organic particles that form the basis of the food webs of the smallest creatures. “If you have to search 30x more to find the same amount of organic matter to feed your metabolism,” you break the entire chain.
When we talk about dumping alkaline matter into the oceans, we’re talking about minerals like basalt or calcium oxide. They help convert the CO2 already present in seawater into carbonates and bicarbonates, making room for more CO2. According to estimates by oceanographers in recent years, the oceans could currently absorb around 38,000 billion tons of CO2. With such an operation we could add several billion tons.
But with consequences that are difficult to predict, according to the study, published April 17 in Environmental Research Letters. In theory, synthetic versions of these minerals could dissolve faster and prove more effective.
Such an “experiment” has obviously never been done on such a large scale (only on a very local scale) and it would require costly infrastructure – to dispose of this ore, but also to retrieve it. A 2018 international study had attempted to estimate the size of the sea fleet this would require, discreetly adding that no in-depth study had been undertaken into the “impact that such alkanization of water would have on marine ecosystems”.