The planet’s ice sheets could melt and raise ocean levels “by several metres” while increasing global warming by just 0.5°C, according to recent studies highlighting hitherto ignored climate interactions. The ice sheets of Greenland and Antarctica, for example, have lost more than 500 billion tons annually since 2000, the equivalent of six Olympic-size swimming pools every second.
Until then, climate models underestimated the contribution of these events to rising sea levels, taking into account only the increase in land temperatures and ignoring the interactions between the atmosphere, ocean, ice sheets, and some glaciers.
A study conducted by researchers from South Korea and the United States proves that if the current climate policies are maintained, the melting of the Antarctic and Greenland ice sheets will raise sea levels by about half a meter by 2050. This figure could rise to 1.4 meters in a worst-case scenario, which from would generate a significant increase in greenhouse gas emissions.
The researchers rely on various scenarios proposed by experts from the United Nations’ Intergovernmental Panel on Climate Change (IPCC).
The study, published this week in Nature Communications, suggests when the uncontrollable melting of ice sheets and glaciers may accelerate.
“Our model sets thresholds between 1.5°C and 2°C for warming, with 1.8°C being our best estimate, for accelerated ice loss and sea level rise,” Fabian Schlosser of the University of California told AFP. Research author.
Temperatures have already risen by nearly 1.2°C worldwide since the pre-industrial era. Scientists know that the ice sheets in West Antarctica and Greenland – which can raise sea levels by up to 13 meters in the long term – have ‘tipping points’ where their rupture is inevitable.
However, the temperatures associated with this phenomenon have not been precisely determined. Other studies published in the journal, on the other hand, show that Thwaites Glacier, in West Antarctica, is cracking in an unprecedented way. This glacier, the size of the UK, has already shrunk by 14km since the 1990s, but the phenomenon has not been fully understood due to a lack of data.
An expedition of British and American scientists drilled a hole as deep as the Eiffel Towers (600 meters) through a thick layer of ice pushed by Thwaites into the Amundsen Sea. They found signs of accelerated erosion and cracks opened by seawater.
“Warm water enters the cracks and contributes to the erosion of the glacier at its weakest point,” said Brittney Schmidt, author of one of the studies and a professor at Cornell University in New York.
Another study published in the journal Earth’s Future highlights that sea level rise will destroy farmland and fresh water sources, forcing millions of people to be displaced sooner than expected.
The authors warn that “the time we have to prepare for increased exposure to flooding may be much shorter than expected.”
The calculations, until then, depended on misinterpreted data. Radar that measures the elevation of coastal areas often confuses treetops with rooftops, placing them at the same level as the ground. This means that the Earth is much lower than previously thought.
This content was developed by the world. Read more articles about sustainability and the environment from O Globo’s perspective at OnePlanet.
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