Carbon dioxide removal (CDR) is the only geoengineering technique that allows negative emissions and the reduction of anthropogenic carbon in the atmosphere. Since the time scales of the global carbon cycle are largely driven by

Oil-burning ships are fertilising the north Pacific with iron – inadvertently putting a proposed geoengineering idea into practice.

When a chartered fishing boat strewed 100 tonnes of iron sulphate into the ocean off western Canada last July, the goal was to supercharge the marine ecosystem. The iron was meant to fertilize plankton, boost salmon populations and sequester carbon. Whether the ocean responded as hoped is not clear, but the project has touched off an explosion on land, angering scientists, embarrassing a village of indigenous people and enraging opponents of geoengineering.

The deliberate injection of particles into the stratosphere has been suggested as a possible geoengineering scheme to mitigate the global warming aspect of climate change. Injected particles scatter solar radiation back to space and thus reduce the radiative balance of Earth. Previous studies investigating this scheme have focused primarily on sulphuric acid particles to mimic volcanic injections of stratospheric aerosol. However, the composition and size of volcanic sulphuric acid particles are far from optimal for scattering solar radiation.

At the United Nations Framework Convention on Climate Change Conference in Cancun, in November 2010, the Heads of State reached an agreement on the aim of limiting the global temperature rise to 2 °C relative to preindustrial levels. They recognized that long-term future warming is primarily constrained by cumulative anthropogenic greenhouse gas emissions, that deep cuts in global emissions are required, and that action based on equity must be taken to meet this objective.

Geoengineering efforts to bring oxygen into the deep Baltic should be abandoned, says Daniel J. Conley.

As researchers find more uses for data, informed consent has become a source of confusion. Something has to change. (Correspondence)

Political interests, not scientists or inventors, will be the biggest influence on technologies to counter climate change, says Jason Blackstock.

As the latest round of United Nations climate negotiations began in Durban, South Africa, expectations could scarcely have been lower. A globally binding deal is further away than ever. That makes considerable warming from climate change inevitable.