According to a comprehensive new study, glaciers around the world are melting at an accelerating rate.
A French-led team evaluated the behavior of almost every recorded ice stream on Earth.
Researchers have discovered that in the first 20 years of the 21st century, they lost about 270 billion tonnes of ice each year.
The meltwater currently produced accounts for about one-fifth of the world’s sea level rise. Scientists talk to Nature Journal..
It’s so hard to imagine the numbers involved, so Robert McNab, a team member at the University of Ulster and the University of Oslo, uses an analogy.
“In the last 20 years, glaciers have lost about 267 gigatons (Gt) per year. Therefore, taking that amount of water and dividing it across the entire Irish island is sufficient to cover everything. 3 each year. Ireland in a meter of water, “he says. This Week’s Science In Action At BBC World Service.
“And total loss is accelerating. It’s increasing by about 48 Gt / year every 10 years.”
The global inventory of glaciers contains 217,175 ice streams.
Some are smaller than soccer fields. Others can be rivals in regions of medium-sized countries like the United Kingdom. Almost all have in common that they are thinning and retreating in the midst of climate change, either due to stronger melting in warm air or due to altered patterns of snowfall supplied to glaciers.
A research team led by Romain Hugonnet of the University of Toulouse, France, used images acquired by Nasa’s Terra satellite, launched in 1999, as its primary data source.
The process of interpreting these photographs and deriving changes in glacier elevation, volume, and mass by 2019 has provided enormous computational power.
The team believes that approach has reduced the uncertainty of results to perhaps less than 5% of the total. And all of the approximately 200,000 glaciers they surveyed are represented on the same methodology.
“This new study is a major advance in achieving high spatial resolution, but it also provides 20 years of temporal variation directly based on satellite data, which is novel,” co-author Matthias Huss said. I will explain. Swiss Federal Institute of Technology.
“This dataset has been validated with a huge amount of additional independent measurements and is so accurate that it greatly reduces the uncertainty of previous studies.”
Announced by a group led by the University of Leeds Unique assessment of glacier ice loss in January In the journal The Cryosphere.
It arrived in a very similar number. An average loss of 289 Gt / year was reported between 2000 and 2019, with an acceleration of 52 Gt / year / 10 years. 8% difference.
Professor Andy Sheppard of Leeds told BBC News: ..
“Glacier melting rates are steadily increasing, but the pace is slowing as ice loss from Antarctica and Greenland is accelerating, and our main concern for future sea level rise. Continues to be. “