{"id":403263,"date":"2026-04-29T12:49:31","date_gmt":"2026-04-29T12:49:31","guid":{"rendered":"https:\/\/www.newsbeep.com\/nz\/403263\/"},"modified":"2026-04-29T12:49:31","modified_gmt":"2026-04-29T12:49:31","slug":"atlantic-current-slowdown-may-reshape-europes-climate","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/nz\/403263\/","title":{"rendered":"Atlantic current slowdown may reshape Europe\u2019s climate"},"content":{"rendered":"

Scientists have found that a major Atlantic ocean current system may weaken<\/a> by about half by the end of this century, far more than many models projected.<\/p>\n

That sharper estimate raises the likelihood of uneven regional climate changes across Europe, even without a full collapse of ocean circulation.<\/p>\n

Evidence sharpens risk
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Across the Atlantic, this overturning system moves warm surface water north and returns colder deep water south, setting the stage for the projected slowdown.<\/p>\n

By matching observed ocean patterns with simulations, Valentin Portmann at the University of Bordeaux<\/a> showed that real-world conditions point toward a much steeper decline.<\/p>\n

That conclusion holds even under moderate future warming scenarios, where earlier projections suggested a more limited weakening.<\/p>\n

Such a gap between model averages and constrained estimates signals that existing projections may be systematically underestimating how much the system can slow.<\/p>\n

Why currents matter<\/p>\n

Across the North Atlantic, this circulation carries warm upper water<\/a> northward and returns colder deep water southward each year.<\/p>\n

Warm water releases heat to the air, then saltier, colder water near Greenland grows dense enough to sink.<\/p>\n

When the sinking weakens, less heat reaches northern seas, and the surrounding atmosphere changes storms, rain, and regional temperatures.<\/p>\n

Major assessments<\/a> expect the circulation to decline this century. An abrupt collapse before 2100 remains less certain and is still debated.<\/p>\n

Models meet measurements<\/p>\n

Many climate models already showed weakening by 2100, but they disagreed widely about how large the decline would become.<\/p>\n

Portmann\u2019s team checked which simulations best matched observed currents, surface temperatures, and salinity \u2013 the amount of salt in seawater.<\/p>\n

Models with fresher South Atlantic water and cooler North Atlantic surfaces tended to make the circulation look too stable in future projections.<\/p>\n

Correcting those biases pulled the forecast downward, showing how small ocean errors can grow into large climate differences.<\/p>\n

Salt changes forecasts<\/p>\n

The strongest correction came from the South Atlantic, where models often made surface waters too fresh.<\/p>\n

Salt helps seawater sink and move, because saltier water becomes heavier when cooling removes heat.<\/p>\n

Too little salt in a model<\/a> can make the overturning seem steadier than the real ocean may be.<\/p>\n

That hidden bias matters because the Atlantic\u2019s future depends on whether heavy northern waters keep sinking.<\/p>\n

Europe feels uneven<\/p>\n

Stronger weakening would not cool every country equally, because Europe\u2019s weather depends on ocean heat, winds, and geography.<\/p>\n

Western coasts nearest the North Atlantic would feel the ocean change more directly than inland areas, especially in winter.<\/p>\n

Colder winters could arrive alongside warmer summers, since greenhouse gases still trap heat across the whole planet through every season.<\/p>\n

Climate planners therefore face mixed risks. Heating trends will continue, while ocean-driven winter patterns become harder to predict.<\/p>\n

Finland avoids extremes<\/p>\n

For Finland, winter cooling is the real concern in research professor Timo Vihma\u2019s analysis at the Finnish Meteorological Institute<\/a>.<\/p>\n

A strong slowdown could cool Finnish winters by a few degrees, while Norway and Iceland could feel more.<\/p>\n

Summers in Finland would still warm through the century as greenhouse gases hold extra heat near the surface.<\/p>\n

\u201cWe cannot talk about an ice age under any circumstances, nor about a Siberian climate coming to Finland,\u201d Vihma said.<\/p>\n

Collapse remains disputed<\/p>\n

Other recent models<\/a> found the circulation continuing in extreme experiments under heavy forcing, although at a much weaker strength.<\/p>\n

Persistent Southern Ocean winds brought deep water upward, keeping enough ocean movement to avoid a full shutdown.<\/p>\n

A broader risk review treated a tipping point \u2013 a threshold where change can feed itself \u2013 as possible but uncertain.<\/p>\n

Those findings limit panic without removing danger. A weakened circulation can still reshape weather and coasts before 2100.<\/p>\n

Preparedness still matters<\/p>\n

Worst-case modeling earns attention because societies often insure against rare events with severe lasting costs.<\/p>\n

Testing harsh scenarios shows which roads, power systems, ports, and farms would struggle first during disruption.<\/p>\n

Lower carbon pollution still reduces the pressure, since less warming means less freshwater entering northern seas.<\/p>\n

Preparing for strong weakening is not surrender, because planning turns uncertain science into practical choices before trouble arrives.<\/p>\n

Limits guide caution<\/p>\n

Future currents cannot be observed directly, so scientists test projected worlds against the best past measurements.<\/p>\n

\u201cIf you want to understand something about the future climate, there is no other approach than climate models,\u201d Vihma said.<\/p>\n

Even good models miss details. The newest forecast depends on which observed clues best explain later change.<\/p>\n

That uncertainty should slow overconfident claims, not delay preparation for a current that is already expected to weaken.<\/p>\n

Planning around uncertainty<\/p>\n

The new estimate, the European climate debate, and competing collapse studies point to one practical lesson: weakening alone carries real consequences.<\/p>\n

Sharper observations can improve the forecast, while faster emissions cuts and local planning reduce the damage if Atlantic change accelerates.<\/p>\n

The study is published in Science Advances<\/a>.<\/p>\n

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