China News Service, September 13th. According to the BBC Chinese website, the Thwaites Glacier in Antarctica, known as the "doomsday glacier", is melting at an alarming rate, raising sea levels, which is worrying More confusing.

British and American scientists recently announced that they have found the answer to this question.

　　Scientists say that the culprit of the glacier melting too fast is the warm current that dives between the bottom of the glacier and the bedrock, and the water temperature is 2 degrees Celsius.

Moreover, with the help of the latest surveying instruments, scientists have mapped out the path of the warm current traversing under the ice.

Data map: Aerial view of Icelandic glaciers.

Image source: Sipaphoto Copyright works prohibited to reprint

　　The latest research results were published in the journal The Cryosphere.

　　Various survey data show that the front end of the Thwaites Glacier is suspended in the air, and the warm ocean current is inserted between the continental shelf and the bottom of the glacier through a huge channel; the greater the ice surface exposed to the water, the more it melts, and the influx of warm water is greater. Great, this forms a vicious circle.

　　According to reports, the gap at the bottom of the glacier is deeper than previously thought, about 600 meters, equivalent to six football fields connected end to end.

　　This warm submarine current is described as the Achilles heel of the Thwaites Glacier with a history of millions of years-the fatal weakness.

　　If Thwaites Glacier continues to melt at the current rate, the ice shelf will eventually collapse, and the earth’s ocean and atmospheric circulation systems will be severely distorted, with worrying consequences.

Secrets of "Doomsday Glacier"

　　Thwaites Glacier is one of the two largest and fastest moving glaciers in Antarctica (the other is Songdo Glacier). It is located in the western part of Antarctica. The thickness of the glacier is 4 kilometers and the area exceeds 180,000 square kilometers, which is slightly smaller than that of the United Kingdom. , About the size of Florida, USA.

　　Thwaites Glacier is considered to be the key to predicting global sea level rise.

Data shows that it has enough ice to raise the sea level by 65 centimeters. It melts into the ice water of the Amundsen Sea, accounting for about 4% of the total global sea level rise.

Data map: A 30-kilometer-long crack appeared on the Pine Island glacier in Antarctica.

　　The National Aeronautics and Space Administration (NASA) announced early last year that it used the latest satellite radar detection technology to discover a huge cave at the bottom of Thwaites Glacier. It is 300 meters high and covers an area of ​​about 40 square kilometers, which can hold 14 billion tons of ice.

Data show that a large part of this cave was formed within three years.

　　The British Antarctic Survey Service (BAS) used an unmanned submarine to survey the water flow at the bottom of the glacier. The results not only detected turbulence formed by a mixture of salt and fresh water, but also measured "warm water" more than 2 degrees Celsius above the freezing point. Water temperature.

　　The profile map drawn from various data shows the path and consequences of the warm current eroding and melting glaciers from the bottom.

　　The research results of NASA and BAS confirmed the suspicion of the scientific community for many years that the front end of the Thwaites Glacier is not the bedrock close to the continental shelf, so the warm current can be embedded between the ice and the sea bed like a shuttle; The faster the glacier melts.

Why is it called "Doomsday Glacier"?

　　Satellite data show that the Thwaites Glacier has retreated significantly since the 1970s. From 1992 to 2017, the ground line of the glacier retreated at a rate of 0.6 to 0.8 kilometers per year.

　　In the 1990s, Thwaites Glacier melted 10 billion tons of ice every year, and now it is almost 80 billion tons.

　　Its collapse will cause global sea levels to rise by about 65 centimeters and will release other major ice bodies in western Antarctica, which together may raise sea levels by 2-3 meters.

　　This will be catastrophic for many countries, including most coastal cities in the world, and it will also make some low-lying islands disappear.

　　However, the greater danger is that the intensity of ocean storms will increase as a result.

　　Professor David Vaughan, head of the British Antarctic Survey and Science Department, said that if the sea level rises by 50 centimeters, the once-in-a-millennium storms may become more frequent and become once-in-a-century; Occurs once in 10 years.

　　The Thwaites Glacier will not completely melt overnight; it will take decades, even more than a century.

　　However, it is undeniable that the continuous increase of carbon dioxide emissions has caused more heat to enter the atmosphere and oceans, which means that the energy in the earth's ecosystem will increase, which will inevitably lead to changes in the global cycle.

　　This phenomenon has already occurred in the Arctic, and signs of the Antarctic are becoming clearer.

Where does the warm current come from?

　　The western part of Antarctica is the place with the most frequent storms on the Antarctic continent. The glaciers here are not as stable as the eastern part and are more affected by climate and ocean currents.

　　The key is that the warm Atlantic current with higher water temperature, from the Gulf of Mexico to the Antarctic, unconsciously scoured the bottom of the glacier and the suspended front edge, causing the ice to melt from the bottom.

　　This warm current from the Gulf of Mexico is heavier because of its salt content, so it sinks below, enters Antarctica with the deep Atlantic ocean current, and joins the ocean currents surrounding the Antarctic continent.

　　The surface water temperature in Antarctica is slightly higher than the freezing point of salt water (-2°C), but the ocean current from the Gulf of Mexico has a temperature higher than the freezing point, about 1°C to 2°C, and is located about 530 meters underwater.

The upper and lower warm ocean currents erode the edge of the glacier all the way, and continue to scour the bottom of the glacier along the tunnels between the glacier and the rocks on the seabed.

　　Due to climate change, the earth is warming, and ocean water temperature is rising.

The increase in the temperature of the Pacific Ocean causes the wind direction on the west coast of the Antarctic continent to change, pushing the warm currents deep in the ocean to become more turbulent.