Summer Arctic sea-ice will disappear before 2050

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Summer Arctic sea-ice is predicted to disappear before 2050, resulting in devastating consequences for the Arctic ecosystem. The efficacy of climate-protection measures will determine how often and for how long. These are the results of a new study involving 21 research institutes from around the world, including McGill University.
Summer Arctic sea-ice will disappear before 2050
Polar bears in the Arctic [Credit: Dirk Notz]

The North Pole is presently covered by sea-ice all year. Each summer, the area of sea-ice coverage decreases and grows again in winter. However, as a result of global warming, the overall area of the Arctic Ocean covered by sea-ice has reduced rapidly over the past few decades. According to the researchers, this substantially affects the Arctic ecosystem and climate. The sea-ice cover is a hunting ground and habitat for polar bears and seals and keeps the Arctic cool by reflecting sunlight.




“While the Arctic sea-ice extent is decreasing during this transition to an ice-free Arctic, the year-to-year variability in extent greatly increases, making life more difficult for local populations and ice-dependent species,” says co-author Bruno Tremblay, Associate Professor in the Department of Atmospheric and Oceanic Sciences at McGill University.
Summer Arctic sea-ice will disappear before 2050
People standing on Arctic sea-ice [Credit: Dirk Notz]

The study published in Geophysical Research Letters analyzed recent results from 40 different climate models. Using these models, the researchers assessed the evolution of Arctic sea-ice cover in a scenario with high CO2 emissions and little climate protection. As expected, summer Arctic sea-ice disappeared quickly in these simulations. Surprisingly, they also found that ice disappeared in some simulations where CO2 emissions were rapidly reduced.

How often the Arctic will lose its sea-ice cover in the future critically depends on future CO2 emissions, the study shows. If emissions are reduced rapidly, ice-free years only occur occasionally. With higher emissions, the Arctic Ocean will become ice-free in most years. This tells us that humans still determine how often the Arctic Ocean will be ice-free in the summer, depending on our future level of emissions, says Tremblay.