Science Heresy - December 2010

WOCE Nitrate concentration at 105W from Antarctica (left) to California (right)

Mixing the Ocean

They that go down to the sea in ships, that do business in great waters; These see the works of the Lord, and his wonders in the deep. - Psalms, 107:23-30, KJV

Section P18 of WOCE (World Ocean Circulation Experiment) showing nitrate concentration of the Eastern Pacific from 67 deg South in the Southern Ocean on the left to Baja California on the right of the image. The maximum concentration lies between 1500 m and 500 m depth North of 25 S. There is very little nitrate South of 45 S where the ocean is well mixed. The peaks in the bathymetry near 26 S are due to a mid-ocean ridge called the East Pacific Rise near Easter Island.

This huge mass of nitrate can be brought to the surface to support a new fishery and sequester CO2.

This idea has been put forward independently by a number of people, notably, Kithill in the US and Lovelock and Rapley in Britain

Lovelock and Rapley proposed bringing nutrients, nitrate and phosphorus, found at depth, to the surface of the ocean in order to remove CO2 from the atmosphere by the ensuing photosynthesis ('Ocean pipes could help the Earth to cure itself', Nature, 449, 403; 2007). Their proposal was criticized by Shepherd et al ('Geo-engineering might cause, not cure,problems' Nature, 449,781;2007).This paper appeared in Nature remarkably soon after the appearance of the Lovelock and Rapley paper (2 weeks).

The thrust of Shepherd et al's argument was that so much CO2 would be brought to the surface that the outcome would be outgassing rather than sequestration

We immediately responded with a closely reasoned argument based on the physical chemistry of CO2 and observed concentrations and temperatures at 4 locations in the Pacific. We demonstrated that CO2 would indeed be sequestered at 3 out of the 4 chosen locations.

This paper was rejected out of hand by the editors of Nature without peer review. The public has been left with the misconception that Lovelock and Rapley (and us) are wrong and that Shepherd et al are correct. Our paper never made it to peer review - its rejection was decided by the editors.

If any criticism can be levelled at Lovelock and Rapley it is that their proposed energy source (ocean surface waves) is unlikely to be sufficiently powerful to provide the required mixing.

Our unpublished Letter to Nature can be downloaded here (245 kB PDF).

A complete description of a scheme to fertilize the ocean and so sequester CO2, reduce ocean acidity and create a huge, new, deep ocean fishery can be found here.

December 2010