John Martin’s iron hypothesis—fertilizing the sea with iron—was first put to the test on the open ocean in 1993. According to Martin’s iron hypothesis, seeding the ocean surface with iron should make microscopic marine organisms like diatoms multiply dramatically, which might in turn cool the planet. The big question is: Should this type of “global engineering” be done?
The research vessel Columbus Iselin was still a ways off when Ken Johnson saw it pass through the Panama Canal and chug toward him. He tensed with a feeling of desperation. The ship was supposed to carry the ocean experiment of the decade, one that could revise textbooks. But to Johnson, the Iselin looked more like a ship that would take the Beverly Hillbillies to sea than a sophisticated research vessel.
A portable laboratory and huge plastic tanks were lashed to the deck. A crane towered near the ship’s center. Barrels of blue-green iron granules crammed the ship. For six weeks, 23 of the world’s top ocean scientists would work in a lab the size of a subway car.