Olive Heffernan

In Correspondence in this week’s Nature, John Shepherd from the National Oceanography Centre, Southampton and colleagues challenge the scheme proposed by James Lovelock and Chris Rapley to help the planet cure itself from the disease of global warming.

For those of you who missed it, a couple of weeks ago, Lovelock and Rapley put forward a geo-engineering solution to climate change in Nature, which involves the installation of large vertical pipes in the ocean that would pump nutrient-rich water from depth to the surface. This, they said, would enhance the growth of algae in the upper ocean, which in turn would transport more carbon to the deep sea.

Now, Shepherd and colleagues claim that the proposed scheme is based on false assumptions. They say the scheme would not lead to enhanced storage of carbon in the deep ocean below 1,000m and in deep ocean sediments, which is necessary for effective long term removal of carbon from the atmosphere. Instead, they maintain the scheme could actually worsen global warming by bringing high levels of particulate carbon back to the surface, where it could be released to the atmosphere. The authors also argue that such large scale engineering solutions could harm fragile ecosystems.

Peter Williams from the School of Ocean Sciences at Bangor University raised some of these same issues on the blog here last week, and also challenged the feasibility of the scheme from an engineering perspective.