Catastrophic Climate Event Looms as Europe Experiences Heatwaves
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As the North experiences fatal heatwaves, looms the ominous forecast of a catastrophic climate event of unprecedented magnitude.
New findings published in Nature Communications suggest the Atlantic meridional overturning circulation, or Amoc, could collapse within the next few decades—maybe even within the next few years—driving European weather to even greater extremes.
The Amoc represents a network of ocean currents in the Atlantic that transfer warm waters towards the north, where they subsequently cool and descend. It is a key reason why Europe’s climate has been stable for thousands of years, even if it’s hard to recognize this chaotic summer as part of that stability.
There is much uncertainty in these latest predictions and some scientists are less convinced a collapse is imminent. The Amoc is just one portion of a broader network of ocean currents that are maintained by wind forces that outlast its collapse. So part of the Gulf Stream will survive an Amoc collapse.
But I have studied the links between Atlantic currents and the climate for decades now, and know that an Amoc collapse would still lead to even greater climate chaos across Europe and beyond. To some degree, it presents an opportunity worth exploring.
Amoc helps keep Europe warm and stable
By comparing the milder clime enjoyed by North Europeans versus those living at parallel latitudes elsewhere, one can appreciate the climate’s alteration caused by Amoc.
Most striking in the northern winter (January) centers to the west of Norway where temperatures are 20°C warmer than the latitude average, thanks to Amoc.
The northeast Pacific—and therefore western Canada and Alaska—enjoys a more modest 10°C warming from a similar current, while prevailing westerly winds mean the northwest Atlantic and northwest Pacific are much colder, as are the adjacent land masses of eastern Canada and Siberia.
The weather and climate of Europe, and northern Europe in particular, is highly variable from day to day, week to week, and year to year, with competing air masses (warm and moist, cold and dry, and so on) gaining or losing influence, often guided by the high-altitude jet stream. The actions of distant entities can prompt alterations in the local environment.
Correlation between sea temperature and weather patterns
In recent times, Europe has borne witness to peculiar weather events occurring during both winter and summer months. At present, strange variations in sea surface heat are manifesting themselves across the North Atlantic. Throughout the ocean, temperature patterns have persisted beyond the typical ranges, with temperatures remaining above or below average by 1°C–2°C for significant durations, covering regions stretching from the tropics to the Arctic.
These designs are evident in their capacity to significantly impact the environment, with the potential to shape the trajectory and intensity of the jet stream.
To an extent, we can attribute some of these sea surface temperature patterns to a changing Amoc, but it’s often not that straightforward. Nevertheless, the association of extreme seasons and weather with unusual sea temperatures might give us an idea of how a collapsed Amoc would unsettle the status quo.
Europe’s northern regions encountered cold waves in succession over these two years. Simultaneously, tropical regions experienced heightened temperatures, which fueled an abnormally stormy hurricane season from June to November in 2010.
During the mid-2010s, a prominent cool patch emerged in the North Atlantic, reaching its zenith during the summer of 2015 when it correlated with hot spells across Central Europe and was one of the isolated areas below its long-term average temperature.
The cold blob looked suspiciously like the fingerprint of a weakened Amoc, but colleagues and I subsequently attributed this transient episode to more local atmospheric influences.
Although the Amoc did not exhibit the same level of involvement as in 2010, the Atlantic experienced another active hurricane season in 2017. Extensive warmth to the northeast in late 2017 may have sustained hurricane Ophelia, emerging around the Azores and making landfall in Ireland in October.
Restructuring of Surface Temperatures
By examining just a handful of cases, we can extrapolate that a deeper restructuring of North Atlantic surface temperatures will have substantial implications for the weather in Europe and worldwide.
Increased temperature variances in larger oceans can modify the nature of weather patterns fueled by heat and humidity from the sea—as temperatures surpass existing extremes, Atlantic storms may become more devastating when they occur. More varied ocean heating trends might translate into unpredictable variations in hurricane courses and jet stream behavior, sending storms to unusual areas not previously seen.
In the event of the Amoc collapse, we can anticipate more pronounced temperature fluctuations, including both extreme heat and cold. The potential climate impacts—on Europe in particular—should add urgency to our decision-making.
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