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Home / Science / Investigation of ripple effects in the shrinkage of Arctic sea ice

Investigation of ripple effects in the shrinkage of Arctic sea ice



Arctic sea ice is one of the most dramatic indicators of climate change. The ice cover of the Arctic Ocean is about half the size of decades ago in a few months, and its thickness has shrunk by an estimated 40%.

Changes in ice can also mean a variety of other changes in the Arctic system and around the world. To better understand this, scientists have frozen an icebreaker next to an ice floe, which they will observe for a full year.

The project is called MOSAiC and is a multidisciplinary drift observatory for studying the Arctic climate. And the key questions they are trying to answer: What are the causes of the decline in the Arctic ice and what are the implications?

Only about 5 degrees from the North Pole, Ocean Physicist Tim Stanton of the Naval Postgraduate School is the next to a hole in the ice, surrounded by tool and equipment boxes.

"All I have to do is bring the & # 39; hairdryer," he says, looking at two electrical connections for a science buoy that needs to be warmed up to a temperature of 1

8 degrees Fahrenheit.

A hair dryer? He explains, "Well, it's an electric hot air gun," he says. "It will curl up your hair, that's for sure!"

Stanton is in the midst of a grueling eight-hour process to install the buoy approximately 24 kilometers from where the MOSAiC ship, the German icebreaker Polarstern, moored.

It is part of a network of devices distributed around the Polarstern and will be independently operated next year. It provides additional data on what is being collected in the central research camp on the ice near the ship.

The buoy is a big banana yellow device, with a whole range of scientific bells hanging from it.

"The flux package is appropriate here," says Stanton, pointing to a cylindrical instrument with sensors running up and down a metal rail that hangs vertically in the water. "And that's what measures the transport of heat, salt and momentum in the water column."

Stanton wants to gather data on these ocean properties because he believes that this may explain why the sea ice disappears as quickly as it is.

"At first glance, it has to be clear, right? They add heat, they melt ice," he says. "But it's so complicated."

While more sea ice melts in summer, it adds fresher water to the top of the ocean. The saltier seawater, which sits lower because it is denser, can form a barrier that prevents the fresher water from falling off.

When this upper water is trapped near the surface throughout the summer, Stanton believes that it can absorb much more heat from the sun, resulting in even more ice melt.

"You can get those fresh, warm layers that, if a bit of wind comes up, mix a bit, really melt the devil out of the ice," he says.

While Stanton asks questions about things that take place under the ice, other scientists look at things that take place over the ice.

For example, Jessie Creamean of Colorado State University tests on the ice a device that collects and counts tiny particles in the atmosphere called aerosols.

"Alright, small aerosol sampler is doing well today," says Creamean, closing a pelican suitcase the size of a carry-on. She has already tested it in Colorado, but today's experiment shows how well it works in the cold.

With aerosols produced by pressurized cans like hairspray, people may be the most familiar, but that's just one kind. Aerosols can also come from natural sources like dust, pollen, mushrooms, or sea salt, and they are in fact the seeds that need clouds to form and grow.

In the Arctic, scientists believe that microbes in the ocean, such as bacteria or algae, can produce aerosols. And Creamean suspects that less ice in the Arctic Ocean could mean more aerosols are being blown out of the water into the atmosphere, sowing more clouds.

The mechanism for this could be twofold: more sunlight entering the ocean with decreasing sea ice, potentially causing more microbial growth, and increased contact between ocean and atmosphere.

MOSAiC scientists are interested in clouds because, like a thermostat, they are important for temperature regulation. Depending on the season, whether clouds are over water or ice, and the properties of clouds, they can cool or warm the earth below.

"This affects how much heat can actually help to melt the sea ice, or it can actually reflect the sunlight from the sea ice," says Creamean. "So it's important to control how much sea ice we have here."

Creamean and Stanton are among hundreds of scientists from various disciplines seeking to better understand this changing region.

"We investigate interactions in the system," says Matthew Shupe, atmospheric scientist at the University of Colorado and the National Oceanic and Atmospheric Administration, and one of the expedition's coordinators.

"How the atmosphere interacts with sea ice, how the ocean interacts with sea ice, the ecosystem, biogeochemical processes," he says.

The overall goal of capturing all this data is to improve the representation of the Arctic in climate models. For example, scientists use these computer simulations to estimate how much the Earth could heat up in the next 50 years.

The better you reflect how reality works in simulation, the better your prediction. But with so little is known about the functioning of the Arctic Ocean, according to Shupe, the predictions on how the Arctic will respond to climate change will fluctuate significantly.

"The Arctic is a place where the models are the least one," he says. "So that tells us that we miss something."

Projecting changes in the Arctic – for example, when the first ice-free summer in the Arctic Ocean begins – is obviously important to the local ecosystem, to Arctic communities, and to anyone interested in commercial activity in the region.

But this research will also help scientists figure out how changes in the Arctic affect other places on Earth. For example, it can help scientists understand the potential links between Arctic warming and extreme weather events in mid-latitudes.

"We need to understand physics and ultimately improve our models that can help us answer these questions," says Shupe.

It will also help scientists predict the speed with which the Greenland ice sheet could melt and increase global sea levels, and improve forecasts of how much global warming will increase in the coming years.

As scientists drift across the Arctic Ocean for the next year and see how all the smaller parts of the Arctic system fit together, they hope to focus more on these big questions.

Copyright 2019 NPR. Further information can be found at https://www.npr.org.


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