Greenland’s ice sheet lost an estimated 600 billion tonnes
The Greenland ice sheets have decreased in mass, directly impacting global see levels, which are likely to continue to rise at even faster rate during 21st century. The 600 billion tons of ice added 2.2mm to global sea levels in 2019. Data from NASA’s Gravity Recovery and Climate Experiment shows that Greenland lost an average of 286 billion tons of ice per year, between 1993 and 2016. This caused global see levels to rise about 8 inches in the last century.
Recent NASA statistics about climate change provide information that the planet’s average surface temperature has risen about 1.62 degrees Fahrenheit (0.9 degrees Celsius) since the late 19th century. Five warmest years on record took place since 2010, with 2016 being the warmest year. For example, in the UK the 2018 was the hottest summer since 2006 and the temperatures continue to rise.
Greenland ice sheet loss it’s not only caused by rising temperatures, but also by unusually clear skies. The article by Courthouse News Service explains:
“Due to the high pressure over Greenland, clouds could not form in the southern portion of Greenland, resulting in abnormally clear skies, letting in more sunlight to melt the surface of the ice sheets. Additionally, with fewer clouds there was about 50 billion fewer tons of snowfall than usual. This lack of snowfall left the dark, bare ice overly exposed in some places. Because ice does not reflect as much sunlight as fresh snow, it absorbed more heat — further contributing to the melting and runoff.”
The ice sheet covers about 80% of the surface of Greenland and consists of layers of compressed snow, being 10,000 feet thick in places. In BBC News article by Matt McGrath, Greenland’s ice sheet was compared to being seven times the area of the UK and up to 2-3km thick in places. The high-pressure weather conditions mentioned before, cause more sunlight hitting the Greenland surface. Lack of snow in other parts of Greenland have equally damaging impacts, making ice bergs absorb more heat and contribute to melt.
There is a popular video uploaded by National Geographic about 4-mile-wide iceberg breaking off the Helheim Glacier in Greenland in 2018, this time-lapse video allows to visualise the transformation happening in front of our eyes. It helps to understand that Greenland does not have a solid layer of ice, National Geographic says that in reality about 80% of the ice sheet’s surface is like a snowcone.
To determine how intensively Greenland ice has melted, IMBIE- international collaboration of polar scientists, published spreadsheet containing the changes in the mass of the Greenland ice sheet between 1980 and 2018.
The statistics are divided in two sections: Greenland Ice Mass and Greenland Equivalent Sea Level. First section provides with information about rate of ice sheet mass change(Gigatons per year) from 79 in 1992, to -144 in 2018. The second one shows rate of ice sheet mass change(millimetres per year) from -0,22 in 1992, to 0,40 in 2018. The statistics present several years of intense melting of Greenland surface; therefore we can predict that the future statistics may raise even more concerns.
The article “Greenland’s melting ice raised global sea level by 2.2mm in two months” published on 19th or March by Oliver Milman, says that ice is being lost from Greenland seven times faster than it was in the 1990s, which puts 400 million people at risk of flooding every year by the end of the century. Article reveals that scientists have calculated that Greenland’s enormous ice sheet lost an average of 268bn tons of ice between 2002 and 2019.
If the Greenland Ice Sheet melted, the sea level would rise about 6 meters. They influence weather and climate- heat radiates to space from the ice sheet surface; it’s layers can tell a lot about Earth’s climate history.
The Greenland ice sheet is roughly 3,000 to 4,000 meters high at its summit and covers roughly 1.7 million square kilometres. Mass gain occurs mostly by snowfall; therefore the recent record number of cloud free days was critical to the melting seen in Greenland. Those days meant 50 billion fewer tonnes being added to the ice sheet.
In essence, there has been many articles providing the data that proves exceptional melting season, which was especially seen in 2012 and 2019. NASA study revealed that Greenland lost 600 billion tons of ice raising sea levels by 2.2 mm, due to unusually warm summer in 2019. According to The Washington Post, the satellites revealed that from 2002 to 2019, Greenland lost 4,550 billion tons of ice for an average of 261 billion tons every year. Studies confirm that Greenland ice sheet is steadily melting, which gives evidence to expect more extreme weather conditions in the future.
By: Julita Waleskiewicz