Could adding pollution to the oceans let us keep polluting the air without causing global climate change?

A 2004 research project in the ocean off the coast of Antarctica seems to have actually worked. Scientists deliberately added 7 tons of dissolved iron to the water, providing nutrients that then triggered an algae bloom. The diatoms and algae in the bloom take in CO2 from surface water. When they die, they sink to the ocean floor carrying the trapped CO2 with them. The resulting lowering of the CO2 content of the surface water makes it more CO2 absorptive, letting it take in more CO2 from the atmosphere. The result is carbon sequestration on the ocean floor and in bottom sediments.

What do you think about such geoengineering? Good idea, or one fraught with more risk than it’s worth? Would the direct approach, just cutting CO2 emissions into the air, be safer?