Study: Collapse of Ocean Currents Could Cause Major Climate Problems
2024-02-19
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1Scientists are warning of the possible collapse of an Atlantic Ocean current system that would likely lead to worldwide climate changes.
2Researchers identify the ocean system as the Atlantic Meridional Overturning Circulation (AMOC).
3They say the system plays an important part in moving, or circulating, salt and warm water around the world.
4This process helps control world temperatures, affects carbon dioxide levels and supports worldwide water flows.
5The AMOC system brings warm water to northern areas and carries cold water south, the U.S. National Oceanic and Atmospheric Administration (NOAA) explains.
6The circulation also transports nutrients necessary to support many kinds of sea life.
7The process begins as warm and salty surface water flows northward toward Greenland in the Atlantic.
8Scientists created "a complex climate model" in an effort to simulate a possible collapse of the AMOC.
9The computer model was "able to measure a sudden weakening of the ocean circulation," the team said in a statement.
10The research was led by scientists from Utrecht University in the Netherlands.
11A study describing their findings recently appeared in the publication Science Advances.
12For thousands of years, Earth's oceans have depended on the AMOC circulation system - which acts like a conveyor belt - to control climate.
13The system is still operating, but has experienced slowdowns in recent years.
14The driver of the conveyor belt sits off the coast of Greenland.
15As more ice melts here from climate change, more freshwater flows into the North Atlantic and slows the circulation, said Rene van Westen.
16He is a climate scientist and oceanographer at Utrecht University.
17Van Westen told The Associated Press his research on a possible AMOC collapse does suggest "we are heading towards a tipping point."
18He added, however, that while his team found clear evidence the system is moving closer to collapse, "we're not sure how much closer."
19In the current system, cold, deeper and fresher water heads south past both Americas and then east past Africa.
20The system also pushes saltier, warmer ocean water from the Pacific and Indian oceans past the southern tip of Africa.
21This water flows to and around Florida before continuing up the U.S. East Coast towards Greenland.
22The Dutch team simulated 2,200 years of AMOC flow.
23The researchers added to the model expectations for future human-caused climate change.
24The results predicted "an abrupt AMOC collapse," after 1,750 years.
25But the researchers noted it is difficult to provide a realistic date because the process could be influenced by many unknown circulation events.
26Making a prediction is also difficult because "current observational records are too short" to provide an exact estimation of collapse, the scientists said.
27The team said more physics-based measuring tools are necessary to create early warning systems.
28The team noted one difficult area to predict is around the tip of Africa, where it is difficult to produce realistic estimates of circulation flows.
29Measurements around that area have a big effect on how much the AMOC slows, the researchers said.
30"This value is getting more negative under climate change," van Westen said.
31He added that when the AMOC reaches a certain level, the change does not happen over time, but would be more "cliff-like," he added.
32Van Westen said an AMOC collapse would mostly affect climate in Europe.
33The researchers say a collapse could reduce temperatures in northwestern Europe by 5 to 15 degrees Celsius.
34Their study predicts the change would also extend Arctic ice much farther south, raise temperatures in the Southern Hemisphere and change worldwide rainfall.
35Some scientists warned the climate effects could cause worldwide food and water shortages.
36In addition, the team said the simulation predicted a possible 100 centimeter rise in European sea levels if the AMOC collapsed.
37Van Westen warned that once the collapse happens, the resulting climate effects are nearly impossible to change.
38Another member of the team, Henk Dijkstra, said staying clear of such a tipping point is necessary to avoid the "devastating consequences on climate, society, and the environment."
39I'm Bryan Lynn.
1Scientists are warning of the possible collapse of an Atlantic Ocean current system that would likely lead to worldwide climate changes. 2Researchers identify the ocean system as the Atlantic Meridional Overturning Circulation (AMOC). They say the system plays an important part in moving, or circulating, salt and warm water around the world. This process helps control world temperatures, affects carbon dioxide levels and supports worldwide water flows. 3The AMOC system brings warm water to northern areas and carries cold water south, the U.S. National Oceanic and Atmospheric Administration (NOAA) explains. The circulation also transports nutrients necessary to support many kinds of sea life. 4The process begins as warm and salty surface water flows northward toward Greenland in the Atlantic. 5Scientists created "a complex climate model" in an effort to simulate a possible collapse of the AMOC. The computer model was "able to measure a sudden weakening of the ocean circulation," the team said in a statement. 6The research was led by scientists from Utrecht University in the Netherlands. A study describing their findings recently appeared in the publication Science Advances. 7For thousands of years, Earth's oceans have depended on the AMOC circulation system - which acts like a conveyor belt - to control climate. The system is still operating, but has experienced slowdowns in recent years. 8The driver of the conveyor belt sits off the coast of Greenland. As more ice melts here from climate change, more freshwater flows into the North Atlantic and slows the circulation, said Rene van Westen. He is a climate scientist and oceanographer at Utrecht University. 9Van Westen told The Associated Press his research on a possible AMOC collapse does suggest "we are heading towards a tipping point." He added, however, that while his team found clear evidence the system is moving closer to collapse, "we're not sure how much closer." 10In the current system, cold, deeper and fresher water heads south past both Americas and then east past Africa. The system also pushes saltier, warmer ocean water from the Pacific and Indian oceans past the southern tip of Africa. This water flows to and around Florida before continuing up the U.S. East Coast towards Greenland. 11The Dutch team simulated 2,200 years of AMOC flow. The researchers added to the model expectations for future human-caused climate change. The results predicted "an abrupt AMOC collapse," after 1,750 years. 12But the researchers noted it is difficult to provide a realistic date because the process could be influenced by many unknown circulation events. Making a prediction is also difficult because "current observational records are too short" to provide an exact estimation of collapse, the scientists said. The team said more physics-based measuring tools are necessary to create early warning systems. 13The team noted one difficult area to predict is around the tip of Africa, where it is difficult to produce realistic estimates of circulation flows. Measurements around that area have a big effect on how much the AMOC slows, the researchers said. 14"This value is getting more negative under climate change," van Westen said. He added that when the AMOC reaches a certain level, the change does not happen over time, but would be more "cliff-like," he added. 15Van Westen said an AMOC collapse would mostly affect climate in Europe. 16The researchers say a collapse could reduce temperatures in northwestern Europe by 5 to 15 degrees Celsius. Their study predicts the change would also extend Arctic ice much farther south, raise temperatures in the Southern Hemisphere and change worldwide rainfall. Some scientists warned the climate effects could cause worldwide food and water shortages. 17In addition, the team said the simulation predicted a possible 100 centimeter rise in European sea levels if the AMOC collapsed. 18Van Westen warned that once the collapse happens, the resulting climate effects are nearly impossible to change. Another member of the team, Henk Dijkstra, said staying clear of such a tipping point is necessary to avoid the "devastating consequences on climate, society, and the environment." 19I'm Bryan Lynn. 20Bryan Lynn wrote this story for VOA Learning English, based on reports from The Associated Press, Utrecht University and Science Advances. 21____________________________________________ 22Words in This Story 23simulate - v. to do or make something that behaves or looks like something real but is not 24conveyor belt - n. a continuously moving piece of equipment used to transport objects from one place to another 25tipping point - n. the time at which a change or effect cannot be stopped 26abrupt - adj. sudden and unexpected 27negative - adj. harmful or bad 28cliff - n. a high area of rock with a very steep side, often along a coast 29devastating - adj. causing a lot of damage or destruction 30consequence - n. a result of a particular action or situation, often one that is bad