Glaciers are disappearing faster than a few years ago

Posted Feb 23, 2020 by Tim Sandle
The rate of melting of Greenland’s glaciers is happening at a far faster rate than climate scientists previously realized. This is based on new data which indicates that the rate of melting is happening below water as well as above.
IceBridge s 23rd flight of the Arctic 2011 campaign surveyed numerous glaciers in southeast Greenlan...
IceBridge's 23rd flight of the Arctic 2011 campaign surveyed numerous glaciers in southeast Greenland including Kangerdlugssuaq Glacier.
NASA Ice Bridge/Michael Studinger
The Greenland ice sheet (Sermersuaq) is a large body of ice that covers some 1,710,000 square kilometers (660,000 square miles), and accounts for some 80 percent of the surface of the country.
Scientists have used data and modelling to assess the rate of glacier melting; however, such data has tended to focus on what is happening on land. An alternative approach from the Alfred Wegener Institute focuses on what is happening underwater too and the findings make for stark reading.
The glaciers are melting seven times faster compared with readings taken during the 1990s. This situation will become worse as sea levels continue to rise. In 2019 Digital Journal presented research that showed global sea levels are set to continue to rise, even if carbon emissions pledges formed as part of the Paris climate agreement are put in place and the environmental goal of a leveling out of global temperatures is achieved. Unfortunately, with sea levels the position is already one of ‘too little, too late’.
The finding is based on a more sophisticated understanding about the underlying mechanisms of ice melting. It is well established that surface ice, exposed to heat (such as from the Sun or rising ambient temperatures), melts. However, ice can also melt from below due to the presence of so-termed 'ice tongues'. These are strips of ice that have moved down into the sea and which are floating on water, although continuing to be attached to land ice. One such tongue, connected to the '79° North Glacier', is 80 kilometers in length.
The '79° North Glacier' has seen a loss of both of mass and thickness over the past twenty years due to a combination of surface and below surface melting. The below surface melting is a consequence of rising sea water temperatures where an acceleration of warm water causes high levels of heat from the ocean to flow past the tongue continuously, melting it from beneath.
The new data reveals the extent of the risk to Greenland’s glaciers and provides a new basis for climate scientists to assess more accurately the quantity of meltwater that the Greenland Ice Sheet is losing each year.
The research has been published in the journal Nature Geoscience, where the research paper is titled “Bathymetry constrains ocean heat supply to Greenland’s largest glacier tongue.”