Guardian: Engineers on the Sleipner East platform in the North Sea can lay claim to a unique environmental honour. Each year for the past decade they have pumped a million tonnes of carbon dioxide into an old gas field below their rig, a helpful contribution to the easing of global warming. But there is more to the project, run by the Norwegian energy company StatoilHydro, than providing the world with some short-term climatic action. The engineers have also been studying the fate of that CO2 …