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+--- Thread: Iron fertilization isn’t going to save us (ocean geoengineering) (/thread-15267.html)
Iron fertilization isn’t going to save us (ocean geoengineering) - C C - Jan 14, 2024
https://hakaimagazine.com/news/iron-fertilization-isnt-going-to-save-us/
EXCERPT: . . . Modeling work published by Tagliabue that looks into ocean iron fertilization—a scenario where just iron is added to the ocean—shows that by the year 2100, the amount of carbon we could trap and store through this technique would amount to about 78 gigatonnes. For context, over just the past four years, the world has emitted about 75 gigatonnes of carbon.
In practice, inefficiencies and unforeseen complications mean iron fertilization would likely lead to even less carbon storage.
For example, setting up a large-scale nutrient fertilization project would require mining the minerals and building infrastructure to get them into the ocean. These activities would emit carbon, lowering the overall carbon sequestration potential by the time the nutrients hit the water. Even at its most efficient, says Tagliabue, “it buys us a handful of years.”
Worse still is the potential for negative side effects. Scientists already expect that nutrient stocks in the upper ocean will decrease as ocean temperatures rise. Tagliabue’s research suggests that the flurry of phytoplankton growth triggered by iron fertilization could also use up the available nitrogen or phosphorus, ultimately leading to a drop in animal biomass in the upper ocean.
Tagliabue didn’t study what would happen if a geoengineer added nitrogen and phosphorus to the mix, too. Doing so could presumably avoid throwing the ocean’s nutrient balance as far out of whack as only adding iron, he says. But increasing the complexity of this marine multivitamin would mean more mining and more infrastructure, complicating the process and likely further reducing the carbon that’s captured and stored.
Other modeling suggests that adding nitrogen and phosphorus to the ocean could reduce oxygen levels and increase the global volume of low-oxygen dead zones by 17.5 percent... (MORE - missing details)