A warming planet might lead to swifter ice loss on Greenland’s ice sheet and faster sea level increases for the rest of the world than previously predicted, scientists said on Monday.
Two separate international studies raised concern about the pace of ice melting on the world’s second-largest ice sheet after Antarctica and suggested that scientists might have underestimated the variable behavior of Greenland’s ice.
“The current models do not address this complexity,” said Beata Csatho, an associate professor of geology at the University at Buffalo and lead author of the paper in the Proceedings of the National Academy of Sciences (PNAS), a peer-reviewed US journal.
Currently, scientists use simulations based on the activity of four glaciers — Jakobshavn, Helheim, Kangerlussuaq and Petermann — to build forecasts of melting into the ocean.
However, the new PNAS study used NASA satellite data to look at nearly 100,000 points of elevation and how they changed from 1993 to 2012, painting a much fuller picture of where melting has happened in the past.
Researchers also came up with a new number for how much ice has been lost in recent years on Greenland’s ice sheet. For the years from 2003 to 2009 — the time period with the most accurate data — 243 gigatonnes of ice were lost annually, adding about 0.68mm of water to the oceans each year, the PNAS study said.
“This information is crucial for developing and validating numerical models that predict how the ice sheet may change and contribute to global sea level over the next few hundred years,” said coauthor Cornelis van der Veen, professor in the department of geography at the University of Kansas.
A second study in Monday’s issue of the journal Nature Climate Change projects that lakes atop Greenland’s ice sheet will become twice as common in the next 50 years as they are today, and by moving from the coasts to the inland areas, they could have a major impact on the way the ice sheet melts.
The bodies of water, known as supraglacial lakes, are darker than other areas, absorbing more sunlight and leaking water that can cause ice nearby to melt.
“Supraglacial lakes can increase the speed at which the ice sheet melts and flows, and our research shows that by 2060 the area of Greenland covered by them will double,” said lead author Amber Leeson from the University of Leeds’ School of Earth and Environment.
When the lakes get large enough, they drain through fractures in the ice, making the entire ice sheet more prone to faster melting.
Using data from the European Space Agency’s environmental remote sensing satellites, they made new simulations of how meltwater will flow and pool on the ice surface to form supraglacial lakes in the years to come.
Greenland’s ice sheet is considered an important factor in sea-level increases said to be a result of climate change and has been expected to contribute about 22cm by 2100.
Since prior projections did not include the changing behavior of these lakes, those projections may be far short, the researchers said, but just how short has yet to be forecast.
“Because ice losses from Greenland are a key signal of global climate change, it’s important that we consider all factors that could affect the rate at which it will lose ice as climate warms,” said coauthor Andrew Shepherd, who is also from the School of Earth and Environment at the University of Leeds. “Our findings will help to improve the next generation of ice sheet models, so that we can have greater confidence in projections of future sea-level rise.”
CONFRONTATION: The water cannon attack was the second this month on the Philippine supply boat ‘Unaizah May 4,’ after an incident on March 5 The China Coast Guard yesterday morning blocked a Philippine supply vessel and damaged it with water cannons near a reef off the Southeast Asian country, the Philippines said. The Philippine military released video of what it said was a nearly hour-long attack off the Second Thomas Shoal (Renai Shoal, 仁愛暗沙) in the contested South China Sea, where Chinese ships have unleashed water cannons and collided with Philippine vessels in similar standoffs in the past few months. The China Coast Guard and other vessels “once again harassed, blocked, deployed water cannons, and executed dangerous maneuvers” against a routine rotation and resupply mission to
GLOBAL COMBAT AIR PROGRAM: The potential purchasers would be limited to the 15 nations with which Tokyo has signed defense partnership and equipment transfer deals Japan’s Cabinet yesterday approved a plan to sell future next-generation fighter jets that it is developing with the UK and Italy to other nations, in the latest move away from the country’s post-World War II pacifist principles. The contentious decision to allow international arms sales is expected to help secure Japan’s role in the joint fighter jet project, and is part of a move to build up the Japanese arms industry and bolster its role in global security. The Cabinet also endorsed a revision to Japan’s arms equipment and technology transfer guidelines to allow coproduced lethal weapons to be sold to nations
‘POLITICAL EARTHQUAKE’: Leo Varadkar said he was ‘no longer the best person’ to lead the nation and was stepping down for political, as well as personal, reasons Leo Varadkar on Wednesday announced that he was stepping down as Ireland’s prime minister and leader of the Fine Gael party in the governing coalition, citing “personal and political” reasons. Pundits called the surprise move, just 10 weeks before Ireland holds European Parliament and local elections, a “political earthquake.” A general election has to be held within a year. Irish Deputy Prime Minister Micheal Martin, leader of Fianna Fail, the main coalition partner, said Varadkar’s announcement was “unexpected,” but added that he expected the government to run its full term. An emotional Varadkar, who is in his second stint as prime minister and at
Thousands of devotees, some in a state of trance, gathered at a Buddhist temple on the outskirts of Bangkok renowned for sacred tattoos known as Sak Yant, paying their respects to a revered monk who mastered the practice and seeking purification. The gathering at Wat Bang Phra Buddhist temple is part of a Thai Wai Khru ritual in which devotees pay homage to Luang Phor Pern, the temple’s formal abbot, who died in 2002. He had a reputation for refining and popularizing the temple’s Sak Yant tattoo style. The idea that tattoos confer magical powers has existed in many parts of Asia