The rise could swamp major cities - including NY and Shanghai - and displace up to 187 million people, according to CNN.
To try and get a more realistic picture of future sea level rise (SLR, ) Jonathan Bamber from the University of Bristol in the United Kingdom and his colleagues used a technique called structured expert judgement (SEJ.) This involved asking 22 ice sheet experts to estimate plausible ranges for future SLR as a result of melting ice in Greenland and the Antarctic under both low and high global temperature rise scenarios.
The vast ice sheets of Greenland and Antarctica contain enough frozen water to lift the world's oceans dozens of metres.
The upper limit for sea level rise by 2100 has previously been estimated between 1.7 and 3.2ft. - the range given in the fifth assessment report from the Intergovernmental Panel on Climate Change (IPCC), the leading worldwide body for the assessment of climate change, in 2013.
Global sea levels could rise by nearly 6ft by 2100 - twice as much as had previously been predicted - threatening major cities and displacing hundreds of millions of people, a study published Monday warned.
Global sea levels could rise in excess of two metres - causing catastrophic consequences for the world, according to a team of worldwide scientists.
The authors said the area of land lost to the ocean could be equivalent to that of France, Germany, Spain and Britain combined and would displace more than 180 million people.
The Paris climate deal, struck between nations in 2015, aims to limit global temperature rises to well below two degrees Celsius, and encourages countries to work towards a 1.5C cap.
The authors of the new study, released Monday in the journal Proceedings of the National Academy of Sciences, argue that the IPCC's sea-level rise prediction was too constrained by focusing on what was "likely" to happen.
Ocean levels are rising due to climate change and the long-held view is that sea levels would rise almost three feet by the year 2100.
"Limiting attention to the "likely" range, as was the case in the IPCC Fifth Assessment Report, may be misleading and will likely lead to a poor evaluation of the true risks", he said.