Ocean fertilization may cause changes in marine ecosystem structure and biodiversity, and may have other undesirable effects.

While controlled iron fertilization experiments have shown an increase in phytoplankton growth, and a temporary increase in drawdown of atmospheric CO2, it is uncertain whether this would increase carbon transfer into the deep ocean over the longer-term.

I've posted before about geo-engineering, and it's potentials, and my fears about it getting out of control. Turns out many others feel the same way.

That really puts the risk in context. We're talking about altering ecosystems of planetary scale for a benefit that won't actually relieve us from dealing with all the other issues, such as conservation or alternative energy generation.

Good article over at Treehugger