An iceberg in the southern ocean, captured by the Chinese icebreaker “Xuelong 2”: The heat waves in Antarctica have been worrying researchers for years
Photo: Liu Shiping / XinHua / picture alliance / dpa
Researchers have for the first time quantified the impact that higher climate targets have on life on the coasts of the world's oceans: If the global community manages to limit global warming to 1.5 degrees, the predicted rise in sea levels could be halved in the 21st century, they say in a study published in the journal Nature.
If the climate targets already submitted by the countries are met, the sea will rise by an average of 25 centimeters by 2100, with 1.5-degree compliant targets only by 13 centimeters.
For the study, the international research team compared the results of hundreds of computer simulations around the world.
If emissions are not drastically reduced, the Intergovernmental Panel on Climate Change now expects an increase of more than one meter by 2100.
According to the authors, glaciers and melting ice sheets are responsible for half of the rise in sea level.
The melting of the Antarctic could lead to a "dramatic" rise in sea levels if the countries do not keep global warming below two degrees Celsius, the study authors said on Wednesday when the study was presented.
Satellite image from February 2020: Icebergs detach from the Pine Island Glacier in Antarctica
Photo: NASA / REUTERS
In a three-degree scenario that controls the world at the current emission levels, the sea level would even rise worldwide by a "catastrophic" five centimeters per year after 2060.
The Antarctic alone could contribute a total of 42 centimeters to the global rise in sea levels in the longer term.
For their calculations, the researchers used a model based on satellite observations, climate data and machine learning to predict ice loss in the region, taking into account various climate targets.
They refer to the UN treaty passed by the states in 2015.
There, the countries undertake to keep the rise in the global average temperature below two degrees and to make efforts to stay at 1.5 degrees if possible.
Massive ice loss after 2060
A "Nature" study, also published this week, comes to similar conclusions. The rate at which the ice is losing in the Antarctic could stabilize at the current level if it warms up from the targeted »below two degrees Celsius«. In the three-degree scenario, however, there could be a sudden increase in ice loss in Antarctica from 2060 onwards. By 2100, this melt alone could cause the sea to rise by around 0.5 centimeters per year. If the temperature increases faster, the value increases accordingly.
"The collapse of the ice sheet is irreversible for thousands of years, and if the Antarctic ice sheet becomes unstable, it could retreat for centuries," said study author Daniel M. Gilford of the Rutgers Earth System Science & Policy Lab.
If the Antarctic should "tip over", even strict climate targets or technologies for removing CO₂ from the atmosphere could not change anything, says Gilford.
Countries like Bangladesh, which are already suffering from extreme storms and floods, are the first to be affected by the rise in sea levels.
Millions of people could be displaced by the rising water.
A study by the American Geophysical Union predicts that more than 1.3 million people could be displaced in Bangladesh alone by 2050.
sug / reuters