Sea Levels Rising Faster than Expected | The Weather Channel:
More than double the average ice loss per year.
I know we have the global coronavirus pandemic to contend with; this is a reminder: climate change marches on, a tiny bit abated by the massive and immediate reduction in the world’s carbon footprint. That’s a little bit of good news.
Greenland’s Superfast ‘Ice Slides’ Could Be Bad News for Climate Change:
Greenland’s ice sheet is sliding way more than previously thought, according to a new study.
This means that the ice sheet can change faster in a warming climate, a group of researchers reported July 10 in the journal Science Advances.
“Understanding ice flow is quite important to predicting future melt from Greenland,” said study lead author Nathan Maier, a doctoral candidate at the University of Wyoming. Ice flows bring ice from the cold interior regions of the Greenland ice sheet to its warmer edges, where the ice melts.
Maier and his team drilled boreholes into the ice using a large drill. They also installed 212 tilt sensors, which measure the amount of deformation and sliding. The researchers took measurements of ice movement from 2014 to 2016, finding that the Greenland Ice Sheet is sliding really, really fast over the underlying bedrock.
Researchers calculate decades of ‘scary’ Greenland ice melting:
The results: during the 1970s, Greenland accumulated 47 gigatonnes of ice per year, on average. Then, it lost an equivalent volume in the 1980s.
The melting continued at that rate in the 1990s, before a sharp acceleration in the 2000s (187 Gt/year) and even more since 2010 (286 Gt/year).
Ice is melting six times faster than in the 1980s, researchers estimate—and Greenland’s glaciers alone have contributed to a 13.7 millimeter rise in sea levels since 1972, they believe.
Rain melts Greenland ice even in winter:
The lead author of the study, Dr Marilena Oltmanns of the GEOMAR ocean research centre in Germany, told BBC News: “We were surprised that there was rain in the winter.
"It does make sense because we’re seeing flows of warm air coming up from the South, but it’s still surprising to see that associated with rainfall.”
Another scientist on the study, Prof Marco Tedesco of Columbia University in New York, said that the increase in rain had important implications.
Even if it falls during winter, and then quickly refreezes, the rain changes the characteristics of the surface, leaving it smoother and darker, and “pre-conditioned” to melt more rapidly when summer arrives.
The darker the ice is, the more heat it absorbs from the Sun – causing it to melt more quickly.
Greenland ice melting ‘even in winter’:
Ocean physicist Dr Neil Fraser at the SAMS laboratories at Dunstaffnage, near Oban, has created a computer model of how huge waves below the surface of the Atlantic are pushing relatively warm water up Greenlandic fjords.
The scientific name is “coastally trapped internal waves”.
They measure 140m from trough to crest.
The waves are warm, although in the Arctic winter this is a relative term, being a few degrees above zero.
They are created by strong winter winds in the northeast Atlantic.
Dr Fraser described it as a “perfect storm scenario”.
He said: “These waves are pushing warm water into the fjord and towards the glacier, causing melting hundreds of metres below the ocean surface.”
Melting of Greenland’s ice is ‘off the charts,’ study shows:
The study, published Thursday in the scientific journal Nature, found that Greenland’s ice loss accelerated rapidly in the past two decades after remaining relatively stable since the dawn of the Industrial Revolution in the mid-1800s.Today, Greenland’s ice sheets are melting at a rate 50% higher than pre-industrial levels and 33% above 20th-century levels, the scientists found.