As Greenland’s ice sheet melts, an island city emerges

For the past four summers, a research team from Columbia University’s Lamont-Doherty Earth Observatory has loaded up a small plane and flown to the town of Aasiaat, located on an island of the same name off the west coast of Greenland. The researchers are heading to the Aasiaat archipelago as part of a project to study how sea levels might change in the area in the coming decades. Their findings – which reveal changes that are different than what most of the world is experiencing as sea levels rise – will help local communities that rely on these waters for their movement and livelihoods.

Aasiaat is an industrial town with roots in aquaculture, located about 25 miles from the coast where the Greenland ice sheet meets the sea. Small, brightly colored houses date back to the colonial era, when buildings were color-coded based on their function: red for commercial buildings, yellow for hospitals, and blue for fish factories. The buildings form a stark contrast to the surrounding icy terrain. In the long winter months there is a blanket of snow on the ground here. In summer, gray metamorphic rock is exposed along the coast and fishing boats line the harbors.

Ships come and go throughout the day according to the tides. The high concentration of nutrients in shallow water, resulting from the mixing of colder salt water with fresh water from glacial melt, promotes the growth of plankton. Marine drifters form the basis of a complex food web, attracting an abundance of fish, seals, whales and seabirds.

The numerous islands and sheltered bays within the Aasiaat archipelago also provide ideal breeding grounds for many marine mammals and seabirds, which the scientists will frequently see in their work. Seals and walruses use the shallow waters to hunt and raise their young. Seabirds such as puffins, fulmars and guillemots nest on the islands’ rocky cliffs. As the world warms and sea levels change, these animals will have to adapt, but so will the residents of cities like Aasiaat. The Columbia researchers’ work will inform the community as it decides exactly how to achieve this.

Seas are rising around the globe. Since 1880, average global sea levels have risen about nine inches. Even if we manage to significantly reduce greenhouse gas emissions around the world, researchers estimate that sea levels around the United States will be two feet higher in 2100 than they were in 2000. But amid this rising swell, Greenland offers a stark contrast. The land and not the sea rises.

“From a U.S. perspective, what we’re most concerned about is flooding, sea level rise and damage from things like that,” says project researcher Kirsty Tinto, a geophysicist at the Lamont-Doherty Earth Observatory. “Here we are talking about sea level decline in a super marine culture.”

As the ice covering Greenland melts, the land freed from its weight gradually rises, a process scientists call isostatic recoil. The pressure that once compressed the Earth’s crust is easing, and Greenland and its coastal islands are growing by millimeters every year.

In addition to this upward movement, melting ice impacts the surrounding ocean. Ice sheets exert a gravitational pull on nearby water, pulling the sea toward the ice mass. As the ice melts, this attraction weakens and the water redistributes around the globe. This redistribution may cause local sea levels near Greenland to fall slightly, while sea levels in more distant regions rise.

“The net effect of the melting of the ice sheet will be a flattening of sea levels, rather than the sea level rise that is occurring in the rest of the world,” says Tinto, “and this is where other questions came into play and intertwine.”

Tinto and her team wanted to find out how Greenland’s coastline would change as sea levels fell. Funded by the National Science Foundation, the project studies four Greenlandic shallow-water communities – Kullorsuaq, Nuuk, Tasiilaq and Aasiaat. In the following years, the researchers want to study the bathymetry – the seabed – of the surrounding waters. They want to give the local community a clearer picture of the emerging seascape and its impact on their lives.

“We can say that sea level in Greenland will fall by one to three meters by 2100, but what does that mean for a person living on the coast if the bathymetry is not accurately mapped?” says Tinto. “What difference does it really make?”

As the land changes and coastal channels become shallower, this could have a major impact on marine life. Some water areas could become cut off from each other, isolating entire regions and blocking the flow of nutrients that keep ecosystems healthy. This shift could be particularly damaging to young fish, which rely on coastal habitats for their growth and development, making it difficult for them to survive. For humans, navigation channels are becoming increasingly shallow and treacherous, and ultimately safe passage may become impossible. Access to the water becomes more difficult as new obstacles appear in the harbor.

“There are no roads between cities. If you want to go between cities, you go by boat,” says Tinto. “Therefore, changing the depth of the harbor is fundamentally as important as roads that run underwater elsewhere.”

In addition to their bathymetry work, the researchers are working with the local community. They enter bathymetry data into an app that is used for navigation, printing maps and storing digital story maps in three languages ​​- Greenlandic, Danish and English. The app will ensure that the science behind future predictions is accessible to the community.

For decades, islanders have observed firsthand the gradual changes in their environment. “The locals have noticed that the rocks are becoming more and more exposed,” says Tinto. “The human time scale can go back a generation or two, which is longer than our instrumental period in this area.”

Aqqaluk Sørensen, a Nuuk local and geophysicist at the Greenland Institute of Natural Resources, shared that older hunters and fishermen in the community have noticed a big change. Small areas of land that were under water 70 years ago are now above the waterline – and can even be used to reduce their fish catches.

“Local people are really interested in the data we collect, especially the bathymetry mapping and seafloor videos,” says Sørensen, who worked on the project. “In many places like Kullorsuaq, there aren’t even maps showing how deep the surrounding seas are. That’s why some of them saw what their own seabed looked like for the first time. For us as scientists, this is a given.”

Sørensen says that primary school textbooks used in the area all predict sea level rise. The researchers’ information has caused the local community to reevaluate its expectations.

Lamont-Doherty geophysicist Robin E. Bell, another researcher on the project, says the study of bathymetry has become a bridge between scientists and the local community. The parties are having meaningful conversations about the changes they are seeing and how they can prepare for the future.

“As with any change, knowing about it will allow the community to adapt to increasing space,” says Bell, who highlights scientists’ efforts to make the information available in local schools and research institutions. “Promoting the growth of Greenland’s scientific expertise will ensure that rising land and falling sea levels are taken into account in future planning of posts, docks and other infrastructure.”

The Greenland ice sheet is already losing ice at an ever-increasing rate. It is one of the largest causes of current sea level rise and its melting is having serious consequences for coastal communities worldwide. However, how quickly and how much the ice sheet will melt depends on future emissions, other climate influences and natural fluctuations within the ice sheet.

Still, the task of making these forecasts meaningful to local communities is equally important. As climate models improve, the focus is shifting to providing actionable insights to regions where sea level rise varies.

“What I find most interesting about this project is that it really connected science to the needs of local communities,” says Fiamma Straneo, an oceanographer and planetary scientist at Harvard University. “Western scientists alone do not know what best meets the needs of a community.”

And it’s not just Greenland that is experiencing sea level rise at a different rate than most of the world. In West Antarctica, for example, the land also rises as the ice melts. The increasing release of freshwater is contributing to global sea level rise, as is melting in Greenland.

“What happens in this ice sheet and how it contributes to the ocean affects absolutely everyone on Earth,” says Tinto, “but figuring out how to make these predictions relevant to an individual community is also very important.”