Ice sheets in Greenland and Antarctica are losing mass at the 'worst case scenario' rate predicted by the UN - and could result in sea levels rising by 16 inches by 2100.
According to a new study by the University of Leeds, if these rates continue, an additional 16 million people could be exposed to repeated annual flooding.
If levels rise by 16 inches over the next 80 years as predicted, there will also be a increase in the number of destructive storm surges, the researchers claim.
Mass loss from 2007 to 2017 due to melt-water and crumbling ice has matched Intergovernmental Panel for Climate Change's (IPCC) most extreme forecasts.
Study lead author, Thomas Slater, an expert in polar observations, said 'we need a new worst case scenario', adding that the sheets were melting faster than predicted.
Mass loss from 2007 to 2017 due to melt-water and crumbling ice has matched Intergovernmental Panel for Climate Change's (IPCC) most extreme forecasts
There is a 'clear mismatch' between the observed reality of ice sheet disintegration and the models that are predicting what will happen in the future, the IPCC said.
The average global temperature during the last Ice Age 20,000 years ago was 46°F (7.7°C) — 11°F (6°C) colder than today — a study has reported.
The average global temperature during the last Ice Age 20,000 years ago was 46°F
Researchers from the US combined data from tiny marine fossils with climate models to forecast the weather during the so-called Last Glacial Maximum (LGM).
During this chilly period, the Earth's ice sheets and glaciers had spread to cover around half of Europe, North America and South America — and much of Asia.
According to the researchers, the difference in the average temperatures between the last Ice Age and now represents a 'huge change'.
The findings will help experts understand the link between changes in atmospheric carbon levels and global temperature shifts — and predict future climate change.
A special IPCC report last year on the planet's frozen regions allowed for only a small increase from Antarctica under the highest greenhouse gas emissions scenario.
Real world observations seem to show those models are no longer accurate as we're already on target to surpass the worst predictions, the team explained.
'Although we anticipated the ice sheets would lose increasing amounts of ice in response to the warming of the oceans and atmosphere, the rate at which they are melting has accelerated faster than we could have imagined,' said Dr Slater.
'We need to come up with a new worst-case scenario for the ice sheets because they are already melting at a rate in line with our current one,' he added.
Being able to properly predict sea level rises over long periods of time is 'critical in helping governments plan climate change mitigation policies', Slater explained.
'If we underestimate future sea level rise, then these measures may be inadequate and leave coastal communities vulnerable.'
Ice sheet losses at the upper end of the IPCC forecasts would by itself expose some 50 million people to annual coastal flooding worldwide by mid-century.
Total sea level rise of at least 3ft would likely require spending upward of £56 billion ($70bn) a year in sea walls and other defences against flooding, the IPCC said.
It looks like the current climate models didn't pay enough attention to ice sheets.
Several factors explain why the climate models underlying UN projections for sea level might have given short shrift to ice sheets, according to the new analysis.
Ice sheet models do well in describing the long-term impact of gradual global warming, which has seen temperatures at the poles rise far more quickly than for the planet as a whole.
But they have failed to account for short-term fluctuations in weather patterns that are, themselves, deeply influenced by climate