To some entrepreneurs, the icy seas between Australia and Antarctica could become a money spinner by engineering nature to soak up carbon dioxide (CO2) and then selling carbon credits worth millions.

To some scientists and many nations, though, the concept of using nature to mop up mankind's excess CO2 to fight global warming is fraught with risk and uncertainty.

An analysis by an Australian body has urged caution and says more research is crucial before commercial ventures are allowed to fertilize oceans.