A swathe of the Greenland ice sheet may be nearing a "tipping point" into a new unstable state of melting that would be irreversible in the short term, scientists warn.
As the central-western Greenland ice sheet melts, it is also shrinking in height, with its surface exposed to warmer temperatures at lower altitudes that contributes further to melting, according to research published on Monday in the journal Proceedings of the National Academy of Sciences.
In a second study published Monday, a different group of researchers highlights how changing snowfall patterns over the Greenland may also cause the ice sheet to absorb more heat.
The two studies are among many in recent months to warn of the increasing rate of ice melt in the Arctic, where climate change is causing temperatures to rise much faster than in the rest of the world.
Greenland's ice sheet the world's second largest after the Antarctic ice sheet is estimated to contain enough water to raise the average sea level by more than 7 metres (23 feet). While it would take centuries for all of that to spill into the ocean under the worst-case scenario, scientists say it is crucial to slow that process by curbing greenhouse gas emissions now.
In examining the relationship between elevation and melt rate, researchers used computer simulations that included factors such as sea-level temperatures, ice melting rates, and ice sheet height. They found that the sheet could be approaching a critical threshold, where the elevation and temperatures at the surface accelerates melting.
"It's a reasonable assessment," said Andrew Shepherd, a polar climate scientist at the University of Leeds who was not involved in the research.
Shepherd noted that the relatively flat surface of Greenland's central western ice sheet likely made it particularly sensitive to this feedback loop.
"If ice melting in Greenland can't be reversed, then it's the latest corner of our planet to be altered for good by global warming,” he said. “Our climate is sick and needs urgent care."
DARKER SURFACE
Meanwhile, a second team examined how a recent high-pressure weather pattern known as "atmospheric blocking" was reducing snowfall for up to weeks at a time, leaving surface snow exposed to solar radiation for longer.
That can change the shape of snowflakes on the ground, making them darker and reducing their reflectivity or "albedo" effect, so they absorb more heat.
"It turns out the shape of the snow grains is really important for determining how reflective the ice sheet is," said co-author Erich Osterberg, a climate scientist at Dartmouth College in Hanover, New Hampshire.
That paper, published in Geophysical Research Letters, drew on data collected over a 10-week snowmobile trek across 4,300 kilometres (2,700 miles) over two summers.
Osterberg said both studies showed how Greenland's surface ice was sensitive to temperature. By contrast, Antarctica's ice sheet is melting largely due to warming ocean water from below.
Reuters
Tue May 18 2021
Fishing vessels are seen next to the icebergs near Ilulissat, Greenland. Filepic/REUTERS
Iran's supreme leader says Hamas leader's death will not halt 'Axis of Resistance'
The "Axis of Resistance", built up with years of Iranian support, includes Hamas, the Lebanese Hezbollah group, the Houthi movement in Yemen, and various Shi'ite groups in Iraq and Syria.
Putin says Russia willing to seek compromises between Iran and Israel
Russia is ready to help seek compromises between arch-foes Israel and Iran, President Vladimir Putin said on Friday, saying these would be difficult but possible.
What proposals will Russia push at the BRICS summit?
The proposal is also to establish a BRICS reinsurance company to allow uninterrupted shipment of goods and key commodities between members.
Indonesia's free meals plan in the spotlight as Prabowo readies for office
Prabowo calls the programme one of the main drivers of economic growth, eventually set to add an estimated 2.5 million jobs.
Astro AWANI's revamped English news website, AWANI International, launches on Oct 21
Astro AWANI's revamped English platform delivers in-depth global news and expert analysis to keep you informed on key developments.
Israeli strikes kill 33 people in Jabalia refugee camp in Gaza, medics say
Residents of Jabalia said Israeli tanks had reached the heart of the camp after pushing through suburbs and residential districts.
Liam Payne's ex-partner calls for media restraint after 'painful' death
Cheryl Tweedy used her statement to urge the media to remember they had a seven-year-old son, Bear, who could read the reports.
Analysts: Indonesia's strong MoF leadership team to boost investor confidence
Sri Mulyani Indrawati as head of Indonesia's Ministry of Finance is expected to instil confidence among investors.
Biden offers both a carrot and a stick to Israel as his term nears an end
Israel has frequently resisted US advice and has caused political difficulties for the Biden administration.
Putin says BRICS will generate most of global economic growth
Russian President Vladimir Putin will host a summit of the group in the city of Kazan on Oct. 22-24.
ISIS Malaysia's perspective of Budget 2025
An excellent rakyat-centric budget under the overarching principle of a caring and humane economy.
Budget 2025: Record increase in STR, SARA aid initiatives
The government will provide a significant boost to the Sumbangan Tunai Rahmah (STR) and Sumbangan Asas Rahmah (SARA) initiatives next year.
Budget 2025: EPF contributions to be made mandatory for foreign workers – PM Anwar
The government plans to make it compulsory for all non-citizen workers to contribute to the Employees Provident Fund (EPF).
What policies to expect from Indonesia's new President Prabowo
Prabowo will be open to foreign investment, his aide has said, such as by offering investors management of airports and sea ports.
Budget 2025: Govt allocates RM470 mil to empower women's participation in PMKS
The Women's Leadership Apprenticeship Program will be intensified as an effort to produce more female corporate personalities.
Israel sends more troops into north Gaza, deepens raid
Residents of Jabalia in northern Gaza said Israeli tanks had reached the heart of the camp, using heavy air and ground fire.
Indonesia ramps up security ahead of Prabowo's inauguration
Prabowo Subianto will be sworn in as Indonesia's president on Sunday with Vice President-elect, Gibran Rakabuming Raka, also taking office.
Immediate allocation of RM150 mil for local authorities, DID to tackle flash floods
Datuk Seri Anwar Ibrahim said this allocation is intended to address the recent flash floods that hit the capital and several major towns.
Budget 2025: Sabah, Sarawak to continue receiving among highest allocations - PM
Sabah and Sarawak continues to be prioritised under Budget 2025, with allocations of RM6.7 billion and RM5.9 billion respectively.
NFOF will be operational in November 2024 with funding of RM1 bil
PM Anwar Ibrahim said NFOF will support venture capital fund managers to invest in startup companies with RM300 million set aside for 2025.