UK-backed mission heads to Greenland to study melting ice

An international team of scientists set sail from Britain on Thursday for Greenland to study rapidly melting ice with drones, mini-submarines and autonomous swimming robots.

The RRS Sir David Attenborough polar research ship was leaving Harwich in southeast England with dozens of international scientists on board. The £20 million, or $27 million, project is led by the British Antarctic Survey and funded by the UK government.

The team plans to spend about five weeks in fjords along southeast Greenland, examining glaciers from several angles. Scientists will use drones with high-resolution cameras and autonomous robots that can dive hundreds of metres to the seabed and attach themselves to ice walls.

Project leader Kelly Hogan, a marine geophysicist at the British Antarctic Survey, said marine robots can reach areas close to the ice that would be unsafe for people.

Greenland's ice sheet contains millions of cubic kilometres of freshwater and is melting rapidly because of global warming. Scientists believe the melt could disrupt important Atlantic currents that help control weather and climate. Researchers have found it difficult to study the melt close up because ice can calve, or break off, without warning.

British marine physicist Mark Inall said scientists still do not fully understand how ocean water melts the ice. The expedition aims to collect detailed observations so Greenland ice melt can be better represented in climate models.

Scientists see signs that large amounts of melting Greenland ice are affecting currents that move warm and cold water around the Atlantic. The current UK climate change model for the next century forecasts disruption of the North Atlantic Subpolar Gyre within decades, with effects on regional fisheries and marine life. Hogan said the best current models suggest such changes could happen as early as the 2040s, while noting that the simulations have inaccuracies.

Paul Holland, an ocean scientist at the British Antarctic Survey who works on modelling data, will be on board to work directly with the findings. He said the problem is urgent and that scientists do not have time to wait for separate research and modelling processes to catch up later.

Holland also pointed to the possible role of melting Greenland ice in changes to the Atlantic Meridional Overturning Circulation, or AMOC, a large ocean current system that helps transfer heat from the tropics to the northern hemisphere. Scientists broadly agree that the AMOC is weakening because of accelerating Greenland melt-off, but there is debate about how quickly this is happening and whether the system could collapse this century.

A shutdown of the AMOC would have serious effects, including much colder winters in northern Europe and higher sea levels around the North Atlantic. Holland said there is major uncertainty, but that rising greenhouse gases are making worse outcomes more likely.

Inall said the idea that AMOC collapse is already inevitable is not currently the consensus view. US glaciologist Erin Pettit said the AMOC appears to be slowing and that this is likely to continue, but said the scale of the impact is part of what scientists hope to understand.