A team of international researchers has set sail for Greenland aboard the UK’s polar research ship RRS Sir David Attenborough, embarking on a six-week expedition to study how rapidly melting fjord glaciers are affecting the Atlantic Ocean and whether they are pushing it towards a critical climate tipping point with serious consequences for the UK and Europe.

The expedition is part of GIANT – Greenland Ice sheet to AtlaNtic Tipping points – a five-year international project led by the British Antarctic Survey and funded by the Advanced Research + Invention Agency. Seventeen partners are involved, including seven international institutions. 

The focus of the expedition is the North Atlantic Subpolar Gyre, a vast whirlpool of ocean currents that influences the Atlantic Meridional Overturning Circulation – the planetary conveyor belt that moves heat and nutrients around the world and keeps regional climates (including Britain’s own) stable.

As Greenland’s glaciers melt at accelerating rates, vast quantities of cold, fresh water are flowing into the North Atlantic. That influx could cap the Subpolar Gyre, preventing the warm, salty water that drives the AMOC from sinking as it normally would – and slowing or disrupting the circulation system that keeps north-western Europe significantly warmer than its latitude would otherwise allow. 

Some estimates suggest this disruption could occur within decades.

Dr Kelly Hogan, a marine geophysicist at the British Antarctic Survey and lead scientist on the GIANT project, said the expedition represents a step change in what researchers are able to measure and understand. 

“We’re in a moment where our tools have finally caught up with our questions. With autonomous vehicles, advanced sensors, and powerful modelling – boosted by AI – we can explore glacier-ocean interactions in ways that were unimaginable just a few years ago,” she said.

The RRS Sir David Attenborough will serve as a floating laboratory off south-east Greenland, near Kangerlussuaq Fjord, where tidewater glaciers flow through long, narrow channels and end in towering ice cliffs up to 100 metres tall. Frequent iceberg calving creates what scientists call an ice mélange – a dense, slushy pack of sea ice and iceberg fragments that can act as a brake on the glacier’s flow into the ocean. When that debris clears in summer, calving rates increase and glaciers can retreat rapidly.

Among the instruments within the scientific toolkit being deployed is Meltstake – a first-of-its-kind sensor that will be lowered by a remotely operated boat and drilled into the ice 100 metres below the surface to measure directly how water transfers heat to the ice face. DriX, a surface-skimming robot, will map the underwater shape of the glacier using scanning sonar and track changes in melt rate on daily or even hourly timescales. A coordinated family of underwater robots – Gavia and EcoSubs – will dive hundreds of metres below the surface in formation, collecting data from the glacial ice face at closer range than any surface vessel could safely approach.

And then there is Boaty McBoatface. The UK’s most celebrated underwater robot – formally known as the Autosub Long Range and developed by the National Oceanography Centre – will dive to 1,500 metres below the ice mélange, mapping its geometry and studying how it affects the surrounding ice and ocean as it melts.

Dr Pierre Dutrieux, an oceanographer at the British Antarctic Survey leading the ocean robotics research aboard the ship, said: “If we want to understand how glaciers melt and fracture, we need to be where the action happens – where the glacial ice meets the ocean. We need these ocean robots to do this – the glacier front is so unpredictable and dangerous, because huge blocks of ice calve into the ocean with little warning. 

“With the fleet of autonomous and remotely controlled instruments we have with us, some of the data we’ll be collecting will be the first of its kind. The DriX will give us a near-live feed of what is happening right at the glacier face – something we wouldn’t have thought possible even a few years ago.”

A small team of researchers will also be camping directly on the ice, deploying an instrument called Adios to measure the glacier’s precise position and rate of movement, using radar to study internal ice layers. Alongside it, GPS-enabled seismic sensors known as Geopebbles will record cracking and calving events in real time.

The urgency behind this data collection lies in a fundamental gap in current climate science. Existing climate models do not accurately represent the complex interactions between Greenland’s glaciers and the warming ocean around them. The data gathered this summer, processed through machine learning and AI, will feed directly into a hierarchy of ice, ocean and climate models – including the next-generation UK Earth System Model, which the GIANT project will equip to better predict how Greenland ice loss drives global climate change.

The team also plans to develop a prototype early warning system capable of providing advance notice of rapid glacier change. It’s hoped it will produce the kind of signal that, if caught early enough, could give policymakers and communities time to prepare for what comes next.

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