The global alarm about rising sea levels and the colossal loss of Earth's ice sheets continues with new results that exceed climate models. According to one scientist, its implications for the future of climate change are "amazing".
"The thaw is outpacing the climate models we use to guide us, and we are in danger of being unprepared for the risks posed by rising sea levels," says Dr. Tom Slater of the Center for Polar Modeling and Observation at the University of Leeds, in the United Kingdom.
Slater, her colleague in Leeds, Dr Anna Hogg, and Danish Meteorological Institute climate scientist Dr Ruth Mottram collaborated on research showing that melt rates so far are following the worst-case scenarios predicted by the Panel. Intergovernmental on Climate Change (IPCC). Their work was published Monday in the journal Nature Climate Change, and it is the latest to warn of sea level projections that may be worse than previously thought.
Since satellite monitoring of ice sheets began in the 1990s, melting Antarctica has raised global sea levels by 7.2mm, with another 10.6mm in Greenland. The latest measurements show that the world's oceans are increasing by 4mm every year; If these rates continue, the ice sheets are expected to raise sea levels to a height that threatens an additional 16 million people with annual coastal flooding by 2100.
If the melting continues at the same rate, it will double the frequency of storm surge flooding in many of the world's largest coastal cities, Hogg says.
The new research is based on a comparison of satellite studies from the Ice Sheet Mass Balance Intercomparison Exercise (IMBIE) with calculations from climate models. It occurs when global ice melting caused by warming temperatures has exceeded thermal expansion, the process by which the volume of seawater expands as it warms, as the main driver of sea level rise .
"It's not just Antarctica and Greenland that are causing the water to rise," warns Mottram. “In recent years, thousands of smaller glaciers have started to melt or disappear completely. … This means that melting ice has now become the main factor contributing to sea level rise ”.
Greenland alone lost a record 532 billion tonnes last year, according to another team of scientists who just published their work 10 days ago. That translates to 3 million tons of extra water every day, or six Olympic-size swimming pools per second. Even a partial melting of the Greenland ice would flood islands and low-lying coastal areas, and this latest study suggests that it is not slowing down.
"Although we anticipated that ice sheets would lose increasing amounts of ice in response to warming oceans and the atmosphere, the rate at which they are melting has accelerated faster than we could have imagined," Slater said.