Adding a bit of iron to the ocean -- the same as is released by a large volcanic eruption -- could do the trick. https://www.google.com/amp/s/www.nextbigfuture

Adding a bit of iron to the ocean -- the same as is released by a large volcanic eruption -- could do the trick. https://www.google.com/amp/s/www.nextbigfuture.com/2018/07/restore-the-oceans-and-get-up-to-50-times-the-fish-and-store-a-trillion-tons-of-co2.html/amp https://www.google.com/amp/s/www.nextbigfuture.com/2018/07/r...