File Blast

2020-2040

The Arctic is becoming free of sea ice

Throughout most of human history, the Arctic served a vital function in maintaining a stable climate – acting as a giant "air conditioner" for the planet by regulating air and ocean currents. The extent and volume of ice in the region stayed relatively unchanged from ancient times until the early modern era.

During the mid-20th century, however, as the worlds population expanded rapidly, man-made emissions of CO2 and other greenhouse gases began to increase at a speed rarely seen in the natural geological record. By the early 21st century, total carbon emissions were exceeding 10 gigatons annually, ten times faster than at any point since the extinction of the dinosaurs.*

Combined with a loss of carbon sinks – through deforestation, soil erosion and other habitat destruction – the resulting accumulation of heat-trapping greenhouse gases in the atmosphere led to a clear warming trend around the globe. This was especially apparent in the Arctic, where temperatures were increasing twice as fast as the worlds average.*

Between 1980 and 2015, the Arctic lost more than 75% of its sea ice volume. The summer ice coverage, in particular, had declined much faster than was originally predicted. Earlier reports from the Intergovernmental Panel on Climate Change estimated that the Arctic would see ice-free summers by 2100. But with record after record being broken, experts were forced to reassess their models and revise their predictions to earlier dates, taking into account feedback mechanisms like the darkening albedo and greater heat absorption from open waters. The first ice-free conditions would occur, not in 2100 – but as early as the summer of 2020.

So-called "blue ocean events" – defined as less than 1 million sq km of ice cover – become commonplace in the 2020s. Initially restricted to September, as the duration of the melt season is extended this condition begins to include additional months on either side of the minimum. By 2025, the Arctic has ice-free conditions from July through to and including November; namely five months of the year. By 2040, just two decades after the initial 2020 event, the Arctic is experiencing an ice-free "blue ocean" all year round.*



arctic sea ice future



By the mid-2020s, the Arctic region has changed from being a carbon sink to a carbon source. In other words, more carbon is being emitted than is being naturally stored. The thaw and release of carbon that was previously locked in permafrost triggers a permafrost carbon feedback (PCF), strong enough to cancel between 42 and 88% of carbon land sinks worldwide.* By the mid-2030s, permafrost is adding more than one billion tons of carbon a year to the atmosphere, equivalent to about 10% of annual man-made carbon emissions globally.

The rapid warming of the Arctic and resulting loss of sea ice is altering the jet stream – changing the movement of weather patterns over North America, Europe and Russia. In a somewhat counterintuitive trend, cold winter extremes in certain parts of the northern hemisphere are becoming more likely and winter storms are being driven further south. This is caused by the increasing moisture capacity of the atmosphere, with about 7% more water vapour being carried for each additional 1°C temperature rise. The shifting jet stream is also influencing the path of hurricanes and worsening their damage.

Another major consequence of the warming Arctic is the release of methane, a greenhouse gas with 86 times the heat-trapping potential of CO2 when measured over a 20-year timescale. Large bursts of methane – some over a kilometre wide – had been observed from the continental shelf seabed of the Eastern Siberian Arctic Shelf in the 2010s. These events are becoming more frequent and more widespread, prompting concerns about the potential for abrupt climatic change. Solar Radiation Management (SRM) technologies are now being given serious consideration, with some early prototypes and small-scale experiments, but the necessary funding and development to fully restore the Arctic is decades away. Some governments are more interested in exploiting the Arctic for its resources, which are easier to access than before.*

The loss of Arctic sea ice is having a serious impact on animal species including the polar bear,* which is now being forced ashore to hunt for berries, birds, eggs and other terrestrial foods.* These provide less energy and nutrition than their traditional, fat-rich prey – ice seals. Two-thirds of polar bears are lost by 2050 and the species is threatened with extinction towards the end of the century.