Reuters: A carbon dioxide store beneath the floor of the North Sea remains tight and is not leaking the greenhouse gas 13 years after storage began, Norwegian oil and gas company StatoilHydro said on Thursday. Companies and scientists have pinned big hopes on carbon capture and storage (CCS) as a future way to curb greenhouse gas emissions and combat global warming, but worries linger that stored carbon dioxide could leak out. “New seismic data from the Utsira formation in the North Sea …