Hot history points to drastic global warming

Earth's hot past suggests future climate change might be far more pronounced than expected, say scientists.

Experts are warning that if carbon dioxide emissions continue at their present rate beyond the end of the century, atmospheric conditions will mirror those of 35 million years ago.

Temperatures then averaged about 31C, which is 16C higher than pre- industrial levels, they claim.

Such a temperature rise would far outstrip current predictions of a 2C to 4C warming by the end of the century.

"If we don't start seriously working toward a reduction of carbon emissions, we are putting our planet on a trajectory that the human species has never experienced," said climate scientist Dr Jeffrey Kiehl, from the National Centre for Atmospheric Research in Boulder, Colorado, who led the study.

"We will have committed human civilisation to living in a different world for multiple generations."

The research is published in the journal Science.