An international team of researchers has set off for Greenland on a six-week expedition to study how quickly the ice sheet’s rapidly melting fjord glaciers are pushing the Atlantic Ocean towards a critical climate tipping point.
The team will travel on the RRS Sir David Attenborough, Britain’s polar research ship, and will use a range of sophisticated equipment, such as a fleet of airborne drones, marine robots, satellites and sensors to study the glaciers and surrounding ocean.
The data collected will be used to improve predictions for the future of Greenland’s glaciers and their impact on the surrounding ocean as they melt.
Their fieldwork is part of a five-year project called GIANT (Greenland Ice sheet to AtlaNtic Tipping points).
This is a large international collaboration of 17 partners (including seven international partners) led by the British Antarctic Survey and funded by the Advanced Research + Invention Agency as part of its Forecasting Tipping Points programme.
Greenland’s rapidly melting ice is adding vast quantities of freshwater into the ocean. Scientists are concerned this could affect a major Atlantic Ocean current system – the North Atlantic Subpolar Gyre.
This ‘whirlpool’ of ocean currents affects the Atlantic Meridional Overturning Circulation (AMOC) – the planet’s ocean conveyor belt that moves heat and nutrients around the world and keeps our planet stable.
The AMOC brings warm, salty water from the tropics to the north. This is cooled by the cold, sub-Arctic air, and sinks. This sinking ocean pulls more water up from the south, driving the three-dimensional conveyor belt of water.
However, fresh, cold meltwater from Greenland’s melting fjord glaciers could put a ‘cap’ on the Subpolar Gyre and reduce the water beneath it from sinking. If this happens, the AMOC could slow, with serious implications for the regional climate, including Britain. Some estimates suggest this change could happen within decades.
Dr Kelly Hogan, a marine geophysicist at British Antarctic Survey who is leading the GIANT research project, explains that “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 says.
The RRS Sir David Attenborough will transport researchers from Britain to south-east Greenland, where they will study tidewater glaciers near Kangerlussuaq Fjord.
These glaciers flow through long, narrow fjords and end in towering ice cliffs, up to 100m tall. Frequent iceberg calving creates an ice mélange; a dense, slushy pack of sea ice and chunks of icebergs that can act as a brake on the glacier and slow its flow into the ocean.
When this debris clears in the summer, calving rates increase and glaciers can retreat rapidly.
Scientists will use this floating laboratory to conduct detailed measurements of fjord depth and shape, as well as ocean temperature, salinity and currents. The ship is also a launch platform for a range of autonomous vehicles that will sample in the hazardous region near the ice.
Using these instruments, researchers will study fjord and glacier behaviour on different scales, looking at individual cracks in the ice to the flow of meltwater and icebergs into the North Atlantic.
Britain’s famous underwater robot – Boaty McBoatface – will also be part of the fleet.
The Autosub Long Range, developed by Britain’s National Oceanography Centre, will dive 1500m deep below the mélange, a chaotic aggregate of icebergs that choke some of the fjords, to map its geometry, and will study how it impacts the surrounding ice and ocean as it melts.
