TWICE as much carbon is locked away in the frozen soils of the earth's permafrost regions as had been thought, raising the concern that global warming will accelerate faster than expected once the soils start to thaw.

A three-year study by an international team of researchers including Pep Canadell of the CSIRO produced the new estimate, based on cores up to three metres deep taken from permafrost regions, particularly across Russia.

Dr Canadell said temperatures near the poles were predicted to rise by as much as 8 degrees by the end of the century. "The world could experience a major melt of large tracts of permafrost in Canada, Russia, Alaska, Norway, Sweden, Finland and Greenland."