Oceans and iron fertilization

Posted: 24 March 2009

Neither the safety nor the effectiveness of ocean fertilization - adding iron or other 'micronutrients' to the sea to encourage plankton to grow - have been established and the method should not be touted as a cure for climate change until they have been.

This advice from the World Conservation Union (IUCN) is based on a Statement of Concern endorsed by the Parties to the London Convention and London Protocol, the international agreements that regulate dumping of wastes and other matter at sea.

According to this "knowledge about the effectiveness and potential environmental impacts of ocean iron fertilization is insufficient to justify large-scale operations".

The idea behind the method is that micronutrients such as iron or urea will stimulate the growth of phytoplankton in the sea, which can absorb large quantities of carbon dioxide from the atmosphere. Studies show little if any potential for long term sequestration but a high likelihood of damage to the marine environment. They have also noted the possibility that ocean fertilization could promote further climate change by stimulating the production of far more potent greenhouse gases, methane and nitrous oxide.

Nevertheless, some companies are already promoting this method and are selling carbon offsets to the public to support their research.