Executive Summary

The proposal

• To add tonnes of iron to the oceans, to reduce the atmospheric greenhouse gas carbon dioxide, to lessen global warming.

The principle

• In the geological record, high levels of iron in the oceans are linked to ice ages
• Many nutrient-rich seas today are unproductive because their iron is limited. These are termed "High Nutrient, Low Chlorophyl" (HNLC) areas
• Adding iron to HNLC areas promotes phytoplankton blooms by remedying the iron deficiency
• These draw additional carbon dioxide out of the atmosphere

The proof required

• To effectively reduce the atmospheric level, any additional carbon drawn into the seas must be permanently stored
• This only happens with burial in sediments on the ocean floor
• There is no proof that this happens during artificial seeding

The problems

• It is not proven that artificial ocean iron fertilisation will cause any significant reduction of atmospheric carbon dioxide
• It is proven that the marine ecology will change as a consequence - and by design. The species-composition of marine communities in fertilised areas changes
• If production is promoted 'up-current', then 'down-current' communities will be deprived of their nitrate and phosphorus nutrient supply
• Many of the keenest advocates are those whose motivation is profit from carbon-trading

The prognosis

• Attempts to 'geoengineer the oceans' to affect the atmosphere could cause extensive problems, both known and unknown - without necessarily achiveing their aim

The practice