Science and Technology

Why scientists want to dump minerals into oceans to fight climate change

M. Ramesh | | Updated on: Dec 20, 2021

Bloom or bust? Algae help sequester carbon dioxide, but could choke other marine life | Photo Credit: Derek Lowe

Minerals can change ocean carbonate equilibrium in a way that the waters can suck out more carbon dioxide

‘Like mixing asafoetida into the ocean (to make the ocean fragrant)’ is an old Tamil saying to illustrate how, sometimes, ‘tiny’ is as good as nothing. But emerging science sees merit in something quite like that to tackle the most profound problem of the current age — climate change.

Believe it or not, scientists are considering dumping minerals into the oceans in order to increase ocean alkalinity. Minerals — the iron-rich olivine, in particular — will change ocean carbonate equilibrium in a way that the waters can suck out more carbon dioxide — trillions of tonnes — from the atmosphere.

Arvind Singh, an assistant professor at the Physical Research Laboratory, Ahmedabad, is onto this and has been awarded the Swarnajayanthi Fellowship to scope oceans for their potential to remove carbon dioxide. He tells Quantum that a gram of olivine can remove 2-3 grams of carbon. Olivine can also be factory-made with negligible carbon footprint, so that solves the problem of availability.

Singh says that increasing ocean alkalinity for carbon dioxide removal is doable, particularly in the ‘upwelling regions’ of oceans, where cold waters rise to the surface from the depths. But the side effects must be studied first — which is a part of his project. Iron, a nutrient, triggers massive algal growth, which while good, as they help in carbon dioxide sequestration, could also use up a lot of oxygen in the water and choke other marine life.

Something like this is happening right now in the Southern Ocean — the waters surrounding Antartica. The Australian wildfires of 2019-20, which burnt down 74,000 sq km of forests (1.5 times the size of Punjab), spewed nutrient-rich aerosols, which settled into the oceans several thousand kilometres away. The result is a massive algal bloom that is twice as big as Australia itself. Scientists are now looking into what happens to the carbon when the algae die and how it will impact marine food chains.

So, if you want to dump minerals into the oceans, be my guest... but first make sure the solution does not create a bigger problem.

Published on December 19, 2021
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