Greenland’s ice sheet melt may raise the world’s sea level by up to 12.6 cm by 2100
Temperature increases on land and high-pressure weather patterns are producing a big melt of Greenland’s ice sheet, a new study confirms.
By 2100, the melting of the Greenland ice sheet is likely to result in up to 12.6 centimetres (nearly five inches) in global sea level rise, researchers predict.
That’s in line with estimates from previous studies, but Danish Meteorological Institute climatologist Ruth Mottram told Nunatsiaq News that there is a risk that “we underestimate the rate at which the ice sheet will melt.”
Mottram and her fellow researchers looked at almost 30 years of scientific data on the melting of the Greenland ice sheet.
In doing so, they were able to establish a link between the change in the last 30 years’ summer temperatures in Greenland and the ice sheet loss.
During 1991 to 2019 there was “significant overall warming in Greenland” of 4.4 C in winter, 2.7 C in spring, and 1.7 C in summer, generally in areas away from the extreme south, according to their study, published this week in the International Journal of Climatology.
Some climatologists say the melting of the Greenland ice sheet, which could contribute as much as seven metres to global sea level rise, is irreversible. (Image from Polar Portal)
The greatest warming was in west and northwest Greenland, of up to 6.5 C in winter.
The researchers found that for every increase in summer temperatures by 1 C, there was a surface mass loss of ice equivalent to about 91 billion tonnes per year on the ice sheet.
Based on this, they were able calculate how much the melting of Greenland’s inland ice will contribute to the global sea level.
Greenland’s ice sheet alone contains enough water to eventually raise global sea levels by as much as seven metres.
Global temperatures are on a path to increase by another 4 C to 6.6 C by 2100, and that increase will be felt even more in the polar regions, Mottram said.
But for the Greenland ice sheet, and “more or less any Arctic glacier,” it’s not just the absolute temperature, but also the weather pattern that is important, she told Nunatsiaq News.
“When there is a big blocking high pressure over the ice sheet, this can give relatively sunny and stable weather with clear skies,” she said. “If these conditions persist a long time, as they did last year, then a large amount of melting can happen, which led directly to the very high melt record.
“This is a weather pattern that climate models often seem to find … hard to get right, and therefore there is a risk that we underestimate the rate at which the ice sheet will melt.”
The Canadian Arctic is likely to experience warming similarly to Greenland, Mottram said.
“The Arctic is warming pretty rapidly in general, so while you won’t necessarily see the same weather, the climate trends will certainly be the same,” she said.
It’s clear that the glaciers in the Canadian Arctic have already lost a lot of ice in the last few decades, she said.
ABOARD ‘ARCTIC SUNRISE’ (Reuters) – Like many of her generation, Mya-Rose Craig feels strongly that adults have failed to take the urgent action needed to tackle global warming and so she has headed to the Arctic Ocean to protest.
Armed with a placard reading ‘Youth Strike for Climate”, the 18-year-old British activist is staging the most northerly protest in a series of youth strikes worldwide.
The strikes, made famous by Swedish campaigner Greta Thunberg, are resuming after a lull caused by the global coronavirus pandemic to draw public attention back to the threat posed by climate change.
“I’m here to… try and make a statement about how temporary this amazing landscape is and how our leaders have to make a decision now in order to save it,” she told Reuters Television as she stood with her placard on the edge of the Arctic sea ice.
“I absolutely think that my generation has always had to think about climate change… which is why as we’ve got older there’s been this massive wave of just this need for change, this demand for change when we realised the grown-ups aren’t going to solve this so we have to do it ourselves.”
Craig, from southwest England, is known as “Birdgirl” online, where her blog chronicling her bird-watching experiences has attracted thousands of followers.
She has travelled hundreds of miles above the Arctic Circle aboard a Greenpeace ship, Arctic Sunrise.
Climate data shows the Arctic is one of the fastest changing ecosystems on the planet, with serious consequences for wildlife from polar bears and seals to plankton and algae, while the melting sea ice contributes to rising sea levels worldwide.
Warming in the Arctic shrank the ice covering the polar ocean this year to its second-lowest extent in four decades, scientists said on Monday.
For Craig, getting to the ice floe involved a two-week quarantine in Germany, followed by a three-week voyage to the edge of the sea ice.
Craig said those who dismiss the youth protests as just a rebellious phase by her generation are wrong, and she wants those in power to stop treating climate change as a low-priority issue, raised only to appease “the lefties in the corner”.
“It’s everything now and it has to be treated like that,” she said.
(Reporting by Reuters Television; Writing by Gareth Jones; Editing by Janet Lawrence)
The fear that action to combat climate change has been too slow has led some scientists to test unconventional methods to stem the loss of Arctic sea ice.
One of the most important, yet underappreciated, features of the Arctic sea ice is the ability of its blindingly white surfaces to reflect sunlight. For at least as long as our species has existed, the frozen seas at the top of our world have acted as a massive parasol that helps keep the planet cool and its climate stable.
Yet now, much of that ice is rapidly vanishing. Rising temperatures have locked the Arctic in a self-destructive feedback loop: the warmer it gets, the reflective white ice dissolves into darker, blue water, which absorbs more of the Sun’s warmth rather than reflecting it back into space. Warmer water accelerates melting, which means yet more absorption of heat, which drives further melting – and so on in a vicious cycle that is part of the reason why the Arctic is warming around twice as fast as the rest of the planet. This July, ice cover was as low as it had ever been at that time of the year.
As planet-warming greenhouse gas emissions continue to rise, some have been driven to explore desperate measures. One proposal put forward by the California-based non-profit Arctic Ice Project appears as daring as it is bizarre: to scatter a thin layer of reflective glass powder over parts of the Arctic, in an effort to protect it from the Sun’s rays and help ice grow back. “We’re trying to break [that] feedback loop and start rebuilding,” says engineer Leslie Field, an adjunct lecturer at Stanford University and chief technical officer of the organisation.
Tiny powder-like beads could increase the reflectivity of Arctic ice, to reflect more of the Sun’s warmth back into space (Credit: Susan Kramer/Arctic Ice Project)
Many scientists frown upon such technological interventions in Earth’s planetary system, known broadly as “geoengineering”, arguing that fiddling with nature might cause further damage. However, “the utter lack of progress on climate mitigation is really opening up a space for all of these [geoengineering] things to be discussed,” says Emily Cox, who studies climate policy and public attitudes towards geoengineering at the University of Cardiff. That said, the urgency does not erase the uncertainty. “What do you do if something goes wrong… especially in the Arctic, which is already a fairly fragile ecosystem?”
Field launched the Arctic Ice Project — formerly known as ICE911 — in 2008, soon after watching the climate change documentary An Inconvenient Truth, which convinced her of the urgency of doing something about the melting sea ice. In particular, it’s the fate of old, thick sea ice that worries her the most – the kind that lasts multiple years. This mature ice, dazzlingly white, has a high albedo, meaning it’s extremely good at reflecting sunlight – much more so than the thinner and darker young ice that forms each polar winter only to melt again during the summer. Yet over the past 33 years, that ice has dwindled by a staggering 95%.
What if, Field asked, she could layer a reflective material on top of the young ice to protect it during the summer months? If it had that extra protection, could it rebuild into sturdy multi-year ice, and kick-start a local process of ice regrowth? She settled on silica – or silicon dioxide – which occurs naturally in most sand and is often used to make glass, as the material of choice. She found a manufacturer that turns it into tiny, brightly reflective beads, each one 65 micrometers in diameter – thinner than a human hair, but too large for them to be inhaled and cause lung problems, Field says. The beads are also hollow inside, so they’ll float on water and continue to reflect away sunlight even if the ice begins to melt.
Over the past decade, she and her team have scattered the silica spheres over several lakes and ponds in Canada and the United States, so far with encouraging results. For instance, in a pond in Minnesota, just a few layers of glass powder made young ice 20% more reflective – enough to delay the melting of the ice. By spring, when the ice in an uncovered area of the pond had completely vanished, there was still nearly a foot of ice in the section treated with the glass beads.
Dark blue water absorbs more of the Sun’s rays, accelerating the process of global warming – but bright white ice reflects that radiation away (Credit: Getty Images)
Field doesn’t want to carpet the Arctic in glass. Instead, she plans on distributing it strategically to protect some particularly fast-melting, vulnerable areas, like the Fram Strait, a thin passage between Greenland and Svalbard. According to results of a climate model she presented last December at the annual meeting of the American Geophysical Union, treating the Fram Strait could lead to large-scale ice regrowth across parts of the Arctic.
Scientists agree that the beads are well-intentioned, but worry about their potential effects on the Arctic ecosystem. If they float around there indefinitely, “it’s just going to clog up the ocean and mess with the ecosystem,” says Cecilia Bitz, an atmospheric scientist at the University of Washington who specialises in Arctic sea ice.
Field argues that the balls are safe because silica is so abundant in nature – indeed, it routinely washes from weathered rocks via rivers into the sea. And according to some safety testing as part of her 2018 study, the beads, when ingested, cause no ill effects in at least two species – sheepshead minnow fish and northern bobwhite birds.
However, some biologists are concerned about the potential effects on the creatures at the base of the Arctic food chain. Depending on how much light the silica beads reflect, they could block sunlight from photosynthesising plankton, such as diatoms, algae that live under the sea ice and around it. Any change in plankton abundance could cascade up the food web and have unpredictable effects on organisms from fish to seals and polar bears, notes Karina Giesbrecht, an ocean chemist and ecologist at Canada’s University of Victoria who has studied the role of silica in Arctic ecosystems.
On top of that, the silica balls are similar in size to diatoms, which are eaten by zooplankton known as copepods, Giesbrecht notes. If the beads sank into the water column, copepods might consume them thinking they are diatoms, without gaining any nutrition. In the worst case, the copepods could starve, with knock-on effects for other members of the Arctic ecosystem.
So far, Field has been using beads that mostly stay afloat (though some inevitably sink each season), and she is planning to test their impact on plankton ecosystems. If there are any harmful effects, she’ll explore ways of tailoring the beads to make them ecologically safer, she says. One option she is considering is whether to tweak their composition such that they dissolve after a period of time. There are many other questions that her team, which is about to undertake further testing in seawater-filled pools in Alaska, will have to answer to convince the world that the approach is safe and effective.
The young, thin Arctic ice is darker and less reflective than the thick, white, old ice – pushing the Arctic into a feedback cycle of warming (Credit: Martha Henriques)
For one, Mark Serreze, a climate scientist who directs the US National Snow and Ice Data Center at the University of Colorado, Boulder, wonders whether they’ll work as intended. “If you put down the silica beads in an area of fast-moving ocean currents, notably the Fram Strait, they will be quickly dispersed,” rendering them ineffective, he says.
The proposal also raises financial questions, like who would foot the approximately $1-5bn (£800m to £4bn) annual bill for making, shipping, testing and distributing the necessary silica beads in the Fram Strait. It may be an eye-watering figure, but it starts to look small next to the estimated $460bn (£360bn) that the United States incurred in extreme weather and climate disasters between 2017 and 2019 alone, Field notes.
Field agrees that geoengineering is in no way a replacement for reducing carbon emissions. Rather, she sees it as a chance to buy the time needed for world economies to decarbonise and stave off the worst impacts of climate change. The silica beads, she says, are “the backup plan I hoped we’d never need”.
During the evening of Tuesday, Sept. 22, a Huntsville parent posted a letter they received from the board confirming a positive COVID-19 case at Spruce Glen Public School in Huntsville.
“We have been notified by the Simcoe Muskoka District Health Unit (SMDHU) that a student or staff member at Spruce Glen Public School has tested positive for COVID-19. Our school is working closely with Trillium Lakelands District School Board and SMDHU and is taking necessary steps to prevent the further spread of the virus both in the school and in the community.”
Follow-up communications confirmed that the person is a female student from Huntsville between the ages of 0 and 17. A parent forwarded this newspaper the letter they received from the school on Wednesday, Sept. 23. Their child is in the same class as the siblings of the student who tested positive for COVID-19.
“The students have all taken their role to keep everyone safe, including themselves safe, very seriously. It is a real blessing! This is such a kind, caring, and amazing group of students. I am deeply moved by their considerate actions,” wrote a teacher at the school.
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