Study identifies link between melting Arctic ice and extreme summer weather in Europe

Most of the Arctic Ocean is surrounded by the coldest parts of the continents of the Northern Hemisphere, bordered by the Arctic regions of Siberia, Alaska, and Canada, with a small opening to the Pacific Ocean through the Bering Strait, and the labyrinth of the Canadian Arctic. There are only a few narrow straits to pass through. islands.

But to the east of Greenland is a vast body of water, about 1,300 miles wide, where the North Pole can spill its icy core into the North Atlantic Ocean. These flows include surges of cold water and fresh water from melting ice, and a new study published in the journal Weather and Climate Dynamics explains how these pulses flow from the ocean to the atmosphere. It shows how it can cause a chain reaction and ultimately cause summer heatwaves and droughts. Europe.

The massive influx of fresh fresh water from melting ice is a relatively new addition to the North Atlantic’s meteorological cauldron, with an ongoing “freshwater anomaly” expected to spread across southern Europe this summer, based on measurements from a new study. likely to cause droughts and heatwaves. said British oceanographer Marilena Ortmans, lead author of the study. National Marine Center.

He said Greenland’s warmth in the summer of 2023 melted a lot of ice and caused more fresh water to flow toward the North Atlantic. Depending on the exact route of the influx, the findings suggest that in addition to the immediate effects this year, there may be a delayed response over the next five years that could trigger heatwaves and droughts in Northern Europe. he said.

Future extreme events will likely resemble the European heatwaves of 2018 and 2022, she added. At the time, the Arctic Circle in Scandinavia and Siberia was experiencing a significant rise in temperature, which led to unusual wildfires in Sweden’s far north. According to a 2019 study published in the journal Nature, much of the Northern Hemisphere was hit by scorching heat that year, with “22 percent of densely populated and agricultural areas affected at the same time between May and July. “We experienced extreme heat.”

A subsequent study found that more than 60,000 people died in a heatwave across Europe from May to August in 2022. Britain reported temperatures of 40 degrees Celsius (104 degrees Fahrenheit) that summer for the first time ever, and the European Union experienced the second-worst wildfire season on record, burning around 3,500 square miles of land.

Meanwhile, 2022 was also the driest year on record in Europe, with 63 per cent of rivers having below-average flows and low flows, disrupting vital river routes and power generation.

Ortmans said the research results will help farmers, industry and communities proactively prepare for specific weather conditions by developing more resilient agricultural practices, predicting fuel needs and preparing for wildfires. He said it will help him plan accordingly.

The effects of changes in freshwater flow into the North Atlantic Ocean have previously been observed on multidecadal timescales in conjunction with periodic and coupled changes in ocean currents and winds, but they have been observed at “very low frequency”. “It was a signal,” she said. “We disentangled the signals.”

Fluctuations are now more frequent and intense, “switching between different states very quickly,” she said, and how changes in the ocean caused by freshwater inflows “have a direct and immediate impact on atmospheric circulation.” He added that the study shows whether the effects of the virus could have a negative impact on the planet and the entire planet. Subsequent weather patterns in Europe.

North American link?

Several recent studies have already shown some of the complex and perhaps unexpected ways in which the changes in the North Atlantic and Arctic recorded in the new study are influencing North American weather and climate patterns. For example, a 2023 paper published in the journal Nature Communications found that a rapid decline in spring snowpack across North America was driving warmer, drier weather patterns in Greenland that were responsible for the meltwater the Oltmanns tracked. suggests that it is.

Changes in fresh, salt, cold, and warm water patterns associated with melting Arctic ice are altering major ocean currents and contributing to a prolonged marine heatwave in the Gulf of Maine, devastating marine life and fisheries. may have a negative impact. Over the past 15 years, the Gulf of Maine region has warmed more than seven times faster than the global average and more than 99 percent of the world’s oceans.

Some studies have shown that the new large influx of freshwater into the North Atlantic has already disrupted a system of heat-transporting currents known as the Atlantic Meridional Overturning Circulation (AMOC), a key Atlantic current that diverts warm surface waters into the Northern Hemisphere. It suggests that you are letting it happen. The cold, deep ocean then returns toward the South Pole. As more warm water accumulates in the region, if it weakens significantly or collapses, it could cause sea levels to rise faster than currently expected along the east coast of North America.

Warmer oceans off the East Coast heat the atmosphere above, and the warm air can carry more moisture. That means when a weather system pushes inland, like Hurricane Irene did in 2011, it dumps more rain. Hurricane Sandy in 2012, which caused $1 billion in damage, was the largest Atlantic hurricane on record before hitting the East Coast.

Will the risk of abnormal summer weather increase?

The influx of fresh water from melting ice creates large temperature differences between the southern and northern parts of the North Atlantic, said Amulya Chebuturi, a hydroclimatic data scientist at the UK Ecohydrology Center (who was not involved in the study). (not).

This would cause the flow of warm water in the North Atlantic to flow further north, displacing the atmospheric jet stream and driving rain storms further north. “This is a phenomenon that has long been associated with warming and drier Europe,” she said. she said.

Research results suggest that the risk of extreme summers in Europe is increasing and increasing, but current climate models are not yet able to accurately simulate future freshwater inputs, so systematic predictions Chebuturi said it was difficult to establish a

He said the findings offer a major opportunity to improve seasonal weather forecasts in Europe. jennifer francisSenior Scientist Woodwell Climate Research Center Located in Falmouth, Massachusetts.

Francis, who was not involved in the study, is concerned with how Arctic warming will affect mid-latitude weather and climate patterns in densely populated and agriculturally important regions of North America and Europe. Many related studies have been conducted on this topic.

Although the full extent of the impact is not yet fully clear, the new study is valuable because it “focuses on one region, which makes it easier to derive specific impacts from the data,” she said. said.

“The melting of Greenland’s ice sheet and additional flow from rivers into the Arctic Ocean are all contributing to the large body of fresher-than-usual water observed south of Greenland,” she said. Ta. The cold mass strengthens temperature differences between different regions of the North Atlantic and changes the jet stream that guides storms.

The study explains how “observations and models can link a series of events, from the loss of sea ice and the influx of freshwater through ocean currents to atmospheric circulation, to show how extreme global warming is.” “This is a step forward in understanding what causes this phenomenon,” he said. Daniela Domeisenwhich studies the dynamics and predictability of weather and climate extremes, was not involved in the new research.

Xavier FettweissPolar researchers at the University of Liège in Belgium, who track the melting of Arctic ice, say this new study shows that the trend towards drier and sunnier conditions in Europe is not just part of a natural cycle. said. He said this result should be understood in conjunction with recently observed changes in AMOC flow.

“It is believed, especially in the general public, that a weakening of the AMOC is associated with cooling in Europe and could locally weaken the effects of global warming,” he said. But a new paper suggests the opposite, he added. The movement of large amounts of fresh water from the Arctic to the Atlantic Ocean “could disrupt systemic circulation in the summer, leading to heat waves and droughts.”