The underlying study is dubious... https://www.nature.com/articles/s41561-019-0499-z https://www.nature.com/articles/s41561-019-0499-z They took 0.5 meters of

The underlying study is dubious... https://www.nature.com/articles/s41561-019-0499-z https://www.nature.com/articles/s41561-019-0499-z They took 0.5 meters of sediment. They examined shells in the sediment, and using a very convoluted and new measurement technique, they found that 'larger' shells were at the bottom (without very much statistical certainty.) And, the study admits that other factors -- such as water temperature -- could effect the size/shell thickness... to what degree is ignored. They then radiodated this 0.5 meter column of sludge, and after making assumptions about this and that and nuclear bomb testing and a host of other assumptions, they determined that the bottom of the 0.5 meter column was from 100 years ago, and the top more recent. (And, of course, they assume the sedimentation was perfectly uniform during the century because... reasons.) And, then you have a graph, showing a decrease in some factor of shells (using a new measuring system) over a span of 100 years (give or take 100 years)... they then claim the decrease is due to CO2, and Voila, the paper is sucked up by Nature. I'm not criticizing the work. I'm sure the researchers would be the first to admit their conclusion is based on a host of assumptions and guesswork. But, what I do find amusing is that a speculative study involving 0.5 meters of mud can get HN readers to begin proposing massive 'de-acidification' plants and fretting about the end of the world.