By Tom Bawden, i news, Friday, 15th May 2020
Scientists have used NASA’s ICES at-2 to measure the thickness of Arctic sea ice, as well as the depth of snow on the ice.
Arctic sea ice is melting so rapidly that it is now 20 percent thinner than it was just over a decade ago, weakening a major source of the planet’s cooling, according to new research.
The ice helps keep Earth cool, as its bright surface reflects the sun’s energy back into space, curbing global warming.
Nasa scientists have been monitoring sea ice levels for decades and identified a “significant” decline between 2008 and 2019, with climate change thought to be largely responsible, according to a new study in the Journal of Physical Research: Oceans.
“The Arctic sea ice pack has changed dramatically since monitoring from satellites began more than four decades ago,” said Nathan Kurtz, ICESat-2 deputy project scientist at Nasa’s Goddard Space Flight Center in Greenbelt, Maryland.
“The Arctic region is a desert – but what snow we do get is very important in terms of the climate and insulating sea ice,” added Ron Kwok, also of Nasa, who wrote another study on Arctic ice, published in the journal JGR Oceans.
This found that snow starts building up slowly in October, when newly formed ice has an average of about five centimetres of snow on it, and “multiyear” ice has an average of 14 cm of snow.
Snowfall picks up later in the winter in December and January and reaches its maximum depth in April, when the relatively new ice has an average of 17 cm and the older ice has an average of 27 cm of snow.
Impact of melting snow
When the snow melts in the spring, it can pool up on the sea ice – those melt ponds absorb heat from the Sun and can warm up the ice faster, just one of the impacts of snow on ice.
These studies are the latest to show that ice around the world – whether on land or in the sea – is melting at an alarming rate that is faster than previously been anticipated.
The melting ice means less sunlight is reflected back into the atmosphere, heating up the land and sea.