Excess carbon dioxide that might otherwise warm the atmosphere as a greenhouse gas could be frozen in huge underground reservoirs, according to British researchers.

The novel way of reducing carbon dioxide emissions is proposed in research published this month in the journal Planet Earth by researchers from the University of Leicester and the British Geological Survey.

The researchers propose storing the gas in a solid form as a gas hydrate or as a pool of liquid CO2. A hydrate is an ice-like crystalline mineral that forms when gas and water freeze together at low temperatures and high pressure, with the frozen water molecules acting as a cage for the gas molecules trapped inside.

Research must be done on hazards

Lab experiments have shown carbon dioxide hydrate should form stable structures in sediments under oceans. Ameena Camps, a PhD research student at the university, has also identified a number of sites in Western Europe with the potential to store the greenhouse gas by this method, including off the coast of Scotland in the North Sea.

Camps did the work alongside Professor Mike Lovell at the university's department of geology and Chris Rochelle from the British Geological Survey.

Lovell said research needs to be done about the potential hazards of naturally occurring methane hydrates before carbon dioxide hydrates could be used as "a potential sink for greenhouse gas emissions."

A report last week from the Intergovernmental Panel on Climate Change said greenhouse gases — particularly carbon dioxide — from human activities such as the burning of fossil fuels is 90 per cent certain to be behind today's hotter temperatures and rising sea levels.