Earth lost 28 trillion tonnes of ice during 1994-2017, sea levels may rise by 17cm by end of century: Study
The authors predict that if the rates continue, the sea levels will rise by 17cm by the end of the century, increasing coastal flooding that could affect an additional 16 million people
A whopping 28 trillion tonnes of ice has vanished from the face of the Earth between 1994 and 2017, according to data from satellite observations. Since the 1990s, the rate of ice loss has shot up by 57%, according to a review.
Ice loss is more pronounced in the Northern Hemisphere due to declining Arctic sea-ice cover, glacier retreat, and Greenland ice sheet melt. The findings are worrying because the polar ice-sheets store more than 99% of Earth’s freshwater ice. And losing even modest amounts of ice could increase sea levels globally — raising coastal flooding and disturbing oceanic currents which help control the climate.
“To put that in context, every centimeter of sea-level rise means about a million people will be displaced from their low-lying homelands,” Professor Andy Shepherd, director of Leeds University’s Centre for Polar Observation and Modelling, told The Guardian. “In the past, researchers have studied individual areas – such as the Antarctic or Greenland – where ice is melting. But this is the first time anyone has looked at all the ice that is disappearing from the entire planet. What we have found has stunned us," he added.
The Earth has been losing a small portion of mountain glaciers since the little ice age — a period that saw cold winters and mild summers. It hit Europe and North America between the 14th and 19th centuries. But a vast majority of the loss can be traced to climate warming, the scientists wrote in their review. The scientists said there is enough evidence to blame climate change for the sea-level loss. Since the 1800s, the surface temperature has risen by 0.85°C, on average. "Although this warming has led to higher snowfall in winter, it has also driven larger increases in summertime surface melting," the researchers wrote in their review. The global oceans have warmed too, dramatically affecting tidewater glaciers [those that end in the sea], floating ice shelves, and the ice streams.
Global sea-levels up by 1.8cm
The Antarctic and Greenland ice-sheets hold enough water to increase sea levels globally by 58m and 7m, respectively. In a new study, researchers found that ice loss in the two regions have raised sea levels by 1.8cm since the 1990s — thereby matching the worst-case climate warming scenarios predicted by the Intergovernmental Panel on Climate Change (IPCC).
The authors predict that if the rates continue, the sea levels will rise by 17cm by the end of the century, increasing coastal flooding that could affect an additional 16 million people. "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,” Dr Tom Slater from the Centre for Polar Observation and Modelling at the University of Leeds said in a statement. “The melting is overtaking the climate models we use to guide us, and we are in danger of being unprepared for the risks posed by sea-level rise.”
The experts highlight that the ice loss from Antarctica and Greenland is not the only concern. "In recent years, thousands of smaller glaciers have begun to melt or disappear altogether, as we saw with the glacier Ok in Iceland, which was declared 'dead' in 2014," Dr Ruth Mottram, study co-author and climate researcher at the Danish Meteorological Institute, said. "This means that the melting of ice has now taken over as the main contributor of sea-level rise."