Your News feature “The oresmen” (Nature 421, 109–110; 2003) characterizes the objectives of GreenSea Venture as strongly in favour of episodic iron fertilization of selected high-nutrient–low-chlorophyll ocean areas, a non-polluting and inexpensive technique. In fact, we believe only that this may be an efficacious approach to controlling the concentration of carbon dioxide in the atmosphere.

Our activities are in support of 'sound science' and the further development of knowledge applicable to iron fertilization as a carbon-control technology. Only with such knowledge can policy-makers determine whether this technology should be developed, together with other approaches, for efforts at climate control.