A reader writes:
What Russ George did was incredibly reckless. Yes, these blooms can sequester carbon dioxide, but if the wrong bloom is promoted, the phytoplankton can also cause massive die-offs in sea life due to either the production of neurotoxins within the algae, or by creating an anoxic environment where there is no oxygen available for respiration due to the abundance of bacteria or other small organisms feeding on the phytoplankton. This is why runoff from farms are monitored for the presence of nitrates and other fertilizers. In the end, such a massive undertaking without any real forethought will do more harm than good.
I am a master's student of climate science, and I was upset to read your positive reaction to Russ George's "enviro-vigilantism."
I too would love to see more passion and direct action on climate change, but Michael Specter is 100% correct that dumping hundreds of tons of iron sulfate into the ocean was reckless and dangerous. While Earth's oceans are a hugely important CO2 sink and in theory one could sequester more carbon by encouraging algae blooms in this way, there's a huge cost. The pH of the ocean has dropped over the past century and is continuing to drop due to absorption of anthropogenic CO2 emissions. That may not sound important, but this increasing acidity is a big problem for the microbes that play a key role in the nitrogen cycle in our oceans, and thus the entire ocean ecosystem. (You can read more about CO2 and ocean acidificaiton here.)
This wasn't an admirable example of non-violent direct action. It was an act of harming an already-troubled ecosystem in favor of another, and apparently without even a scientific assessment to determine if the trade-off was worth it. So please don't encourage this type of "enviro-vigilantism."
George's actions run the risk of doing harm to the environment – we simply don't know. And by not including any kind of assessment, there's no way for anyone to tell whether or not George's actions are working, not working, or wreaking havoc in unforeseen ways. He risks doing harm to others without providing any means for the world to tell if he's actually doing any counterbalancing good or not.
You also leave out a telling bit of George's motivation: money. As the piece you linked to and several other articles point out, he is seeking carbon credits he can sell on the carbon exchange market. Of course, how the value of any potential credits could be calculated or assigned without data is left unanswered.
To borrow a phrase from Adam Savage of the Mythbusters, "The difference between screwing around and science? Writing it down." Russ George is screwing around, and he's doing it with the planet.