It may cover a staggering 656,650 square miles (1.7 million square km), but the Greenland Ice Sheet's vast expanse is more vulnerable to the effects of climate change than previously thought. Researchers have developed a  model revealing that despite the sheet's size and stability, the surface beneath it makes it more sensitive to movement. This movement causes different parts of the ice to move at different speeds, causing ice to shear - a phenomenon known as ice flow. This ultimately releases more ice into the ocean, adding to the rising sea levels. Researchers have developed a climatic model which reveals that, despite the Greeland Ice Sheet's (pictured) size and stability, the weak sediment on the surface beneath it makes the sheet more sensitive to movement, caused by rising global temperatures. This increases the amount of ice released into the oceans . The model was designed by researchers at Cambridge University. As well as assessing the impact increasing meltwater has on ocean levels each year, the model also took into account the role that the soft, spongy ground beneath the ice sheet plays in its changing dynamics. The Greenland Ice Sheet - the second-largest in the world, covering an area roughly eight times the size of the United Kingdom - contains enough ice to raise sea levels by more than 23ft (7 metres) if it were to be lost altogether. Using a 3D ice sheet model, together with an observational record of surface melting, researchers from Cambridge University were able to accurately reproduce how the ice sheet’s seasonal movement changes in response to the amount of surface meltwater being delivered to the ground below. Not only is the ice sheet sensitive to a changing climate, but extreme meteorological events, such as heavy rainfall and heatwaves, can also have a large effect on the rate of ice loss. The soft sediment beneath the sheet gets weaker as it tries to soak up more water, making it less resistant, so that the ice above moves faster. As a result, the researchers state that the Greenland Ice Sheet is not nearly as stable as first thought. Currently, due to surface melting alone, it is losing ice at a net annual rate of 200 gigatonnes, equating to 0.02 inches (0.6mm) of sea level rise. By comparison, sea levels globally are rising at 0.18 inches (3mm) annually. A similarly large, but ultimately more uncertain source of sea level rise, has been blamed on the movement of this ice sheet. These shifts additionally cause ice to be discharged into the ocean, and these movements are caused by rising temperatures. Study leader Dr Marion Bougamont, of Cambridge’s Scott Polar Research Institute, said: ‘When these large ice sheets melt, whether that’s due to seasonal change or a warming climate, they don’t melt like an ice cube. ‘Instead, there are two sources of net ice loss: melting on the surface and increased flow of the ice itself, and there is a connection between these two mechanisms which we don’t fully understand and isn’t taken into account by standard ice sheet models.’ Other models of the Greenland Ice Sheet have typically assumed the ice slides over hard and impermeable bedrock. The model was designed by researchers at Cambridge University. As well as assessing the impact increasing meltwater has on ocean levels each year, the model also took into account the role that the soft, spongy ground beneath the ice sheet (pictured above left and below right)  plays in its changing dynamics . Using a 3D ice sheet model, together with an observational record of surface melting, researchers were able to accurately reproduce how the ice sheet’s seasonal movement changes in response to the amount of surface meltwater being delivered to the ground below . This latest study incorporates new evidence from ground-based surveys, which revealed soft and porous sediments at the bed of the ice sheet - similar to the soft and muddy bottom of a lake. The study, published in the journal Nature Communications, specifically identifies the intake and temporary storage of water by weak sediment beneath the ice sheet as a crucial process in governing ice flow. Using a 3D ice sheet model, together with an observational record of surface melting produced by colleagues at Aberystwyth University, Dr Bougamont and Dr Poul Christoffersen were able to accurately reproduce how the ice sheet’s seasonal movement changes in response to the amount of surface meltwater being delivered to the ground below. Last week, canyons, lakes and mountains were revealed in the most detailed maps ever made of the hidden world beneath the polar regions.Surveys of the Antarctic and Arctic revealed features buried under the ice including a ‘mega canyon’ in Greenland (illustrated) - bigger even than the Grand Canyon in the US . Dr Christoffersen said: ‘Not only is the ice sheet sensitive to a changing climate, but extreme meteorological events, such as heavy rainfall and heatwaves, can also have a large effect on the rate of ice loss. Global warming could be triggering increasingly cold winters in some parts of the world, scientists have claimed. They discovered a link between rising ocean temperatures, and a large pocket of cold air known as the polar vortex. Researchers led by Baek-Min Kim from Korea Polar Research Institute found that as oceans heat up and melt the Arctic ice, warm air is released that destabilises polar air and sends cold blasts into the atmosphere. The polar vortex was responsible for the extreme and freezing temperatures experienced in the US last winter, they continued. ‘The soft sediment gets weaker as it tries to soak up more water, making it less resistant, so that the ice above moves faster. The Greenland Ice Sheet is not nearly as stable as we think.’ Last week, canyons, lakes and mountains were revealed in the most detailed maps ever made of the hidden world beneath the polar regions. Surveys of the Antarctic and Arctic revealed features buried under the ice including a ‘mega canyon’ in Greenland - bigger even than the Grand Canyon in the US. And data from surveys of the regions has revealed the extent to which Arctic sea ice is gradually decreasing and how long it might take to disappear. The unseen land under the ice was detailed in the new edition of the Times Comprehensive Atlas of the World. While previous maps of the polar regions showed them as mostly near-blank whiteness, the latest data has allowed the appearance of the land under the ice to be revealed. And the maps show the dramatic decline in Arctic sea ice in recent decades as the region is affected by rising global temperatures .
The model was created by researchers at Cambridge University .
It assessed the impact of increasing levels of annual meltwater .
The model also took into account the soft, spongy ground beneath the sheet .
Previous research has typically assumed ice slides over hard bedrock .
But, ground-based surveys have more recently identified a more porous sediment beneath the Greenland Ice Sheet .
This weak sediment leads to greater movement, which increases ice flow .
It may cover a staggering 656,650 square miles (1.7 million square km), but the Greenland Ice Sheet's vast expanse is more vulnerable to the effects of climate change than previously thought. Researchers have developed a  model revealing that despite the sheet's size and stability, the surface beneath it makes it more sensitive to movement. This movement causes different parts of the ice to move at different speeds, causing ice to shear - a phenomenon known as ice flow. This ultimately releases more ice into the ocean, adding to the rising sea levels. Researchers have developed a climatic model which reveals that, despite the Greeland Ice Sheet's (pictured) size and stability, the weak sediment on the surface beneath it makes the sheet more sensitive to movement, caused by rising global temperatures. This increases the amount of ice released into the oceans . The model was designed by researchers at Cambridge University. As well as assessing the impact increasing meltwater has on ocean levels each year, the model also took into account the role that the soft, spongy ground beneath the ice sheet plays in its changing dynamics. The Greenland Ice Sheet - the second-largest in the world, covering an area roughly eight times the size of the United Kingdom - contains enough ice to raise sea levels by more than 23ft (7 metres) if it were to be lost altogether. Using a 3D ice sheet model, together with an observational record of surface melting, researchers from Cambridge University were able to accurately reproduce how the ice sheet’s seasonal movement changes in response to the amount of surface meltwater being delivered to the ground below. Not only is the ice sheet sensitive to a changing climate, but extreme meteorological events, such as heavy rainfall and heatwaves, can also have a large effect on the rate of ice loss. The soft sediment beneath the sheet gets weaker as it tries to soak up more water, making it less resistant, so that the ice above moves faster. As a result, the researchers state that the Greenland Ice Sheet is not nearly as stable as first thought. Currently, due to surface melting alone, it is losing ice at a net annual rate of 200 gigatonnes, equating to 0.02 inches (0.6mm) of sea level rise. By comparison, sea levels globally are rising at 0.18 inches (3mm) annually. A similarly large, but ultimately more uncertain source of sea level rise, has been blamed on the movement of this ice sheet. These shifts additionally cause ice to be discharged into the ocean, and these movements are caused by rising temperatures. Study leader Dr Marion Bougamont, of Cambridge’s Scott Polar Research Institute, said: ‘When these large ice sheets melt, whether that’s due to seasonal change or a warming climate, they don’t melt like an ice cube. ‘Instead, there are two sources of net ice loss: melting on the surface and increased flow of the ice itself, and there is a connection between these two mechanisms which we don’t fully understand and isn’t taken into account by standard ice sheet models.’ Other models of the Greenland Ice Sheet have typically assumed the ice slides over hard and impermeable bedrock. The model was designed by researchers at Cambridge University. As well as assessing the impact increasing meltwater has on ocean levels each year, the model also took into account the role that the soft, spongy ground beneath the ice sheet (pictured above left and below right) plays in its changing dynamics . Using a 3D ice sheet model, together with an observational record of surface melting, researchers were able to accurately reproduce how the ice sheet’s seasonal movement changes in response to the amount of surface meltwater being delivered to the ground below . This latest study incorporates new evidence from ground-based surveys, which revealed soft and porous sediments at the bed of the ice sheet - similar to the soft and muddy bottom of a lake. The study, published in the journal Nature Communications, specifically identifies the intake and temporary storage of water by weak sediment beneath the ice sheet as a crucial process in governing ice flow. Using a 3D ice sheet model, together with an observational record of surface melting produced by colleagues at Aberystwyth University, Dr Bougamont and Dr Poul Christoffersen were able to accurately reproduce how the ice sheet’s seasonal movement changes in response to the amount of surface meltwater being delivered to the ground below. Last week, canyons, lakes and mountains were revealed in the most detailed maps ever made of the hidden world beneath the polar regions.Surveys of the Antarctic and Arctic revealed features buried under the ice including a ‘mega canyon’ in Greenland (illustrated) - bigger even than the Grand Canyon in the US . Dr Christoffersen said: ‘Not only is the ice sheet sensitive to a changing climate, but extreme meteorological events, such as heavy rainfall and heatwaves, can also have a large effect on the rate of ice loss. Global warming could be triggering increasingly cold winters in some parts of the world, scientists have claimed. They discovered a link between rising ocean temperatures, and a large pocket of cold air known as the polar vortex. Researchers led by Baek-Min Kim from Korea Polar Research Institute found that as oceans heat up and melt the Arctic ice, warm air is released that destabilises polar air and sends cold blasts into the atmosphere. The polar vortex was responsible for the extreme and freezing temperatures experienced in the US last winter, they continued. ‘The soft sediment gets weaker as it tries to soak up more water, making it less resistant, so that the ice above moves faster. The Greenland Ice Sheet is not nearly as stable as we think.’ Last week, canyons, lakes and mountains were revealed in the most detailed maps ever made of the hidden world beneath the polar regions. Surveys of the Antarctic and Arctic revealed features buried under the ice including a ‘mega canyon’ in Greenland - bigger even than the Grand Canyon in the US. And data from surveys of the regions has revealed the extent to which Arctic sea ice is gradually decreasing and how long it might take to disappear. The unseen land under the ice was detailed in the new edition of the Times Comprehensive Atlas of the World. While previous maps of the polar regions showed them as mostly near-blank whiteness, the latest data has allowed the appearance of the land under the ice to be revealed. And the maps show the dramatic decline in Arctic sea ice in recent decades as the region is affected by rising global temperatures .
as ice flow. This ultimately releases more ice as assessing the impact increasing meltwater has melting, researchers from Cambridge University Greenland Ice Sheet have typically assumed the ice slides over hard and impermeable bedrock. The model was designed by researchers at Cambridge year, the model also took into account the role that the soft, spongy ground beneath the ice new evidence from ground-based surveys, which water by weak sediment beneath the ice sheet as a