Ice Loss in Greenland and Antarctica

An aerial view of the icebergs near Kulusuk Island, off the southeastern coastline of Greenland. Credit: NASA Goddard Space Flight Center

In almost 30 years, Earth has lost a total of 28 trillion tonnes of ice from its surface. By examining satellite surveys of the planet’s poles, glaciers, and mountains, scientists were and can measure how much ice coverage is lost due to global heating triggered by rising greenhouse gas emissions. These carbon emissions continue to rise as global temperatures continue to soar; however, they question if these gases are to blame. As the Arctic continues to warm faster than any other part of the planet, the current rate of ice-melt in Greenland and Antarctica tracks the “worst-case scenario,” menacing our lives, especially the ones living in the coastal areas around the world.

“Stories like these need to dominate the news if we are to have a chance of avoiding the worse case scenarios of the climate crisis.” – Greta Thunberg

Greenland

Changes in the Greenland ice sheet’s contribution to global sea level, 1992 to 2017. Credit: ESA/NASA/Planetary Visions

Compressed over time, accumulated snowfall eventually results in glaciers. On account of the combination of both sea and atmospheric temperatures accelerating in Greenland, the discharge and runoff surpasses accumulation and results in ice loss. When an area of high air-pressure lingers over Greenland, the shift to north-streaming air happens. These zones of fixed air, referred to as a “block,” have gotten more continuous in the Arctic and highly contributes to the changes in temperatures.

With an ice sheet of nearly two miles thick in certain areas, if all ice were to melt, sea levels in Greenland would rise about 24 feet (7.5 meters). At the current rate of loss, Greenland’s ice represents around a one-quarter inch every time of the worldwide total rise of around one and a quarter inches for each decade.

In 2019, Greenland’s amount of ice loss reached and shattered the previous record by 15% with a reported 586 billion tons (532 billion metric tons) of ice melting. To put it in perspective, that is more than 140 trillion gallons (532 trillion liters) of water, which is enough to cover California in more than four feet (1.25 meters) of water. About 50% of Greenland’s ice was lost in July due to the effect of an irregular and unusual heatwave.

“Not only is the Greenland ice sheet melting, but it’s melting at a faster and faster pace,” expressed Ingo Sasgen, a geoscientist at the Alfred Wegener Institute in Germany.

Antarctica

Changes in the Antarctic ice sheet’s contribution to global sea level, 1992 to 2017. Credit: IMBIE/Planetary Visions

Ledges of ice that jut out from the edge of the continent and into the ocean are called ice shelves. Its function is to keep glaciers stable and in place, but as ice shelves melt, they become thinner, weaker, and bound to break. At the point when this occurs, such as in Antarctica, they can release streams of ice from the glaciers behind them, raising worldwide sea levels. 

Furthermore, many researchers believe that climate change is contributing to the melting ice shelves influencing certain wind patterns around Antarctica. This can cause the amount of warm water in the Southern Ocean to increase and studies are suggesting that as the Earth keeps on warming, the process may become more serious and intense.

Since the mid-1990s, Antarctic ice shelves have lost a reported nearly 4.4 trillion tons (4 trillion metric tons of ice). It appeared that the melting accelerated in the late 2000s, before inevitably easing back down again during the 2010s. “If the ice shelves were in a stable, steady-state, then they might oscillate back and forth between gaining mass and losing mass.” Though, for the last 25 years, “there’s always mass loss.” “It goes from a small amount of mass loss to a large amount of mass loss to a small amount of mass loss again. It never goes from mass gain to mass loss,” noted Adusumilli noted Susheel Adusumilli, a doctoral student at the Scripps Institution of Oceanography at the University of California, San Diego.

Worst-Case Scenario

According to researchers and the flaws seen in the ongoing climate change models, the Greenland and Antarctica ice sheets are currently melting at a pace steady with the United Nation’s (UN) and the Intergovernmental Panel on Climate Change’s (IPCC) worst-case-scenario predictions for sea-level rise. Both ice sheets hold a sufficient amount of frozen water to be able to lift seas 65 meters and at the current melting rate, could add 17 centimeters* to the present-day sea levels by the end of the century.

The effects found in the different studies were very alarming and concluded that if sea levels rise following the direst outcome imaginable, the real most dire outcome imaginable could be significantly more critical. For example, our humanity, especially coastal cities and towns around the world, are already threatened of being not prepared for the impacts, and this worst-case-scenario is currently predicted to expose 44 to 66 million people to yearly coastal flooding. To be completed next year, a new generation of climate models that are more reliable and better reflect how ice sheets, the seas, and the atmosphere interact will support the IPCC’s next significant report.

*Each centimeter of ocean level ascent indicated that around a million people will be dislodged from their low-lying homelands and countries.

Sources:

Fountain, Henry. “Loss of Greenland Ice Sheet Reached a Record Last Year.” The New York Times, The New York Times, 20 Aug. 2020, www.nytimes.com/2020/08/20/climate/greenland-ice-loss-climate-change.html

Harvey, Chelsea. “Antarctica’s Ice Shelves Have Lost Millions of Metric Tons of Ice.” Scientific American, Scientific American, 12 Aug. 2020, www.scientificamerican.com/article/antarcticas-ice-shelves-have-lost-millions-of-metric-tons-of-ice/.

McKie, Robin. “Earth Has Lost 28 Trillion Tonnes of Ice in Less than 30 Years.” The Guardian, Guardian News and Media, 23 Aug. 2020, www.theguardian.com/environment/2020/aug/23/earth-lost-28-trillion-tonnes-ice-30-years-global-warming

Press, Associated. “Record Melt: Greenland Lost 586 Billion Tons of Ice in 2019.” NBCNews.com, NBCUniversal News Group, 21 Aug. 2020, www.nbcnews.com/science/environment/record-melt-greenland-lost-586-billion-tons-ice-2019-rcna91

Marlowe Hood, AFP. “Ice Sheet Melting Is Perfectly in Line With Our Worst-Case Scenario, Scientists Warn.” ScienceAlert, ScienceAlert, 2 Sept. 2020, www.sciencealert.com/ice-sheet-melting-is-perfectly-in-line-with-our-worst-case-scenario-scientists-warn/amp

Julia Conley, staff writer. “’Worst-Case Scenario’ of Melting Ice and Sea Level Rise Coming to Pass, Warn Researchers.” Common Dreams, Common Dreams, 3 Sept. 2020, www.commondreams.org/news/2020/09/03/worst-case-scenario-melting-ice-and-sea-level-rise-coming-pass-warn-researchers?amp

Rosane, Olivia. “Greenland and Antarctica Already Melting at ‘Worst-Case-Scenario’ Rates.” EcoWatchRoar, EcoWatch, 3 Sept. 2020, www.ecowatch.com/amp/greenland-antarctica-ice-melting-rate-2647425507.

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