By Mark Kinver Environment reporterPublished1 day agoShare
In our monthly feature, Then and Now, we reveal some of the ways that planet Earth has been changing against the backdrop of a warming world. The shrinking sea-ice in the Arctic is not only a sign of climate change, it is causing the planet to warm more quickly. This is because more sunlight is being absorbed by the darker ocean, rather than being reflected back into space.https://flo.uri.sh/visualisation/6397277/embed?auto=1
Arctic sea-ice plays an important role in controlling the planet’s temperature, and any problem with this natural thermostat is a cause for concern.
Figures from the US space agency (Nasa) suggest the loss of the minimum Arctic sea-ice extent is in the region of 13.1% per decade, based on the 1981 to 2010 average.
The disappearance of the sea-ice in a warming world also contributes to rising average surface temperatures. The sea-ice is estimated to reflect 80% of sunlight back into space, meaning it does not warm the surface.
But when the sea-ice has melted, the darker ocean surface is exposed, which absorbs about 90% of the sunlight hitting it. This results in warming of the region.
This phenomenon is known as the Albedo effect, and it occurs because light surfaces reflect more heat than dark surfaces.
The freezing and thawing of the ocean in the Arctic is a seasonal occurrence, with the freezing peaking in March and the melting reaching its maximum in September.
However, data from on-the-ground observations and from satellites tell us that the extent of sea-ice in the Arctic polar region is declining as the planet warms.
As this occurs, the albedo (or reflectivity) is reduced, because the dark ocean waters absorb more heat than the lighter sea-ice. This in turn causes the land and oceans to warm even more.
Ultimately, scientists fear, the increasing amount of ground being exposed in regions traditionally covered with snow will trigger a “tipping point”. This is where the warming of the atmosphere reaches a point where human interventions will no longer be able to halt it.
Smaller and warmer world
Another impact of the decreasing density of ice in the northern polar region is the opening of the Northwest Passage. This trading route links the North Atlantic Ocean with the North Pacific Ocean.
Since the 19th Century, there has been clamour to find a navigable route through frozen Arctic waters between Greenland and Canada’s Arctic islands.
It has long been a deadly pursuit for mariners who braved the frozen seascape. However, some experts estimate that the route will become commercially viable in the near future as the sea-ice retreats in the summer months.
For some, it is going to revolutionise the global shipping sector. For others, it is a disaster waiting to happen.
Environmental groups fear a growing volume of shipping traffic through the pristine Arctic waters will damage slow-growing, long-lived marine ecosystems.
They particularly fear a ship encountering a mishap in the remote polar waters, resulting in a potentially devastating pollution incident.
Lack of food
Evidence suggests that the thinning sea-ice is affecting wildlife, including top-of-the-food-chain predators such as polar bears. The ice is not strong enough to support the animals’ weight, forcing them to embark on energy-sapping swims and making it more difficult to catch prey.
As well as causing starvation, it is also reportedly resulting in bears coming into human settlements looking for food.
Another concern among scientists is that melting sea-ice is affecting a major ocean current in the Arctic – the Beaufort Gyre.
Freshwater is less dense than salty seawater. The researchers said a sudden influx of freshwater from the Arctic Ocean into the northern Atlantic Ocean could alter the strength of the current.
This is because the force pushing water down the eastern coast of continental North America will be reduced, resulting in a smaller volume of warmer tropic waters from equatorial regions being displaced towards western Europe.
Models suggest the reduction in warmer waters heading towards western Europe will result in lower temperatures in the region. This, in turn, would also affect weather patterns in the global climate system.
Our Planet Then and Now will continue each month up to the UN climate summit in Glasgow, which is scheduled to start in November 2021
First global assessment of the extent of snow and ice cover on Earth’s surface—a critical factor cooling the planet through reflected sunlight—and its response to warming temperatures.
The global cryosphere—all of the areas with frozen water on Earth—shrank by about 87,000 square kilometers (about 33,000 square miles), a area about the size of Lake Superior, per year on average, between 1979 and 2016 as a result of climate change, according to a new study. This research is the first to make a global estimate of the surface area of the Earth covered by sea ice, snow cover, and frozen ground.
The extent of land covered by frozen water is just as important as its mass because the bright white surface reflects sunlight so effectively, cooling the planet. Changes in the size or location of ice and snow can alter air temperatures, change the sea level and even affect ocean currents worldwide.
The new study is published in Earth’s Future, AGU’s journal for interdisciplinary research on the past, present, and future of our planet and its inhabitants.
The percentage of each area that experiences ice, snow or frozen ground at some point during the year (1981-2010). Credit: Peng et al. (2021) Earth’s Future https://doi.org/10.1029/2020EF001969
“The cryosphere is one of the most sensitive climate indicators and the first one to demonstrate a changing world,” said first author Xiaoqing Peng, a physical geographer at Lanzhou University. “Its change in size represents a major global change, rather than a regional or local issue.”
The cryosphere holds almost three-quarters of Earth’s fresh water, and in some mountainous regions, dwindling glaciers threaten drinking water supplies. Many scientists have documented shrinking ice sheets, dwindling snow cover, and loss of Arctic sea ice individually due to climate change. But no previous study has considered the entire extent of the cryosphere over Earth’s surface and its response to warming temperatures.
Contraction in space and time
Peng and his co-authors from Lanzhou University calculated the daily extent of the cryosphere and averaged those values to come up with yearly estimates. While the extent of the cryosphere grows and shrinks with the seasons, they found that the average area covered by Earth’s cryosphere has contracted overall since 1979, correlating with rising air temperatures.
The shrinkage primarily occurred in the Northern Hemisphere, with a loss of about 102,000 square kilometers (about 39,300 square miles), or about half the size of Kansas, each year. Those losses are offset slightly by growth in the Southern Hemisphere, where the cryosphere expanded by about 14,000 square kilometers (5,400 square miles) annually. This growth mainly occurred in the sea ice in the Ross Sea around Antarctica, likely due to patterns of wind and ocean currents and the addition of cold meltwater from Antarctic ice sheets.
Sea ice melting in the Arctic Ocean. Credit: NASA/Kathryn Hansen
The estimates showed that not only was the global cryosphere shrinking but that many regions remained frozen for less time. The average first day of freezing now occurs about 3.6 days later than in 1979, and the ice thaws about 5.7 days earlier.
“This kind of analysis is a nice idea for a global index or indicator of climate change,” said Shawn Marshall, a glaciologist at the University of Calgary, who was not involved in the study. He thinks that a natural next step would be to use these data to examine when ice and snow cover give Earth its peak brightness, to see how changes in albedo impact the climate on a seasonal or monthly basis and how this is changing over time.
To compile their global estimate of the extent of the cryosphere, the authors divided up the planet’s surface into a grid system. They used existing data sets of global sea ice extent, snow cover, and frozen soil to classify each cell in the grid as part of the cryosphere if it contained at least one of the three components. Then they estimated the extent of the cryosphere on a daily, monthly, and yearly basis and examined how it changed over the 37 years of their study.
The authors say that the global dataset can now be used to further probe the impact of climate change on the cryosphere, and how these changes impact ecosystems, carbon exchange, and the timing of plant and animal life cycles.
Reference: “A Holistic Assessment of 1979–2016 Global Cryospheric Extent” by Xiaoqing Peng, Tingjun Zhang, Oliver W. Frauenfeld, Ran Du, Haodong Jin and Cuicui Mu, 16 May 2021, Earth’s Future. DOI: 10.1029/2020EF001969
Sea ice across much of the Arctic is thinning twice as fast as previously thought, researchers have found.
Arctic ice is melting as the climate crisis drives up temperatures, resulting in a vicious circle in which more dark water is exposed to the sun’s heat, leading to even more heating of the planet.
The faster ice loss means the shorter north-eastern shipping passage from China to Europe will become easier to navigate, but it also means new oil and gas extraction is more feasible.
Calculating the thickness of sea ice from satellite radar data is difficult because the amount of snow cover on top varies significantly. Until now, the snow data used came from measurements by Soviet expeditions on ice floes between 1954 and 1991. But the climate crisis has drastically changed the Arctic, meaning this information is out of date.
The new research used novel computer models to produce detailed snow cover estimates from 2002 to 2018. The models tracked temperature, snowfall and ice floe movement to assess the accumulation of snow. Using this data to calculate sea ice thickness showed it is thinning twice as fast as previously estimated in the seas around the central Arctic, which make up the bulk of the polar region.
Robbie Mallett of University College London, who led the study, said: “Sea ice thickness is a sensitive indicator of the health of the Arctic – and, when the Arctic warms, the world warms.
“Thicker ice acts as an insulating blanket, stopping the ocean from warming up the atmosphere in winter and protecting the ocean from the sunshine in summer. Thinner ice is also less likely to survive during the Arctic summer melt.”
Changes in the Arctic are also increasingly believed to influence extreme weather such as heatwaves and floods around the northern hemisphere. The rapid thinning of sea ice has consequences for human activities in the Arctic as well.
The newly exposed waters enabled storms to hit coastal communities and erode coasts, Mallett said. The opening of the shorter north-eastern shipping route around Siberia means less fuel is needed to transport goods between China and Europe, leading to lower carbon emissions.Advertisementhttps://1800dead54a5b54ff32446a37838d191.safeframe.googlesyndication.com/safeframe/1-0-38/html/container.html
In February, a cargo ship made a round trip for the first time in winter. “However, this also raises the risk of fuel spillages in the Arctic, the consequences of which could be dire,” said Mallett.
“There’s also a lot of interest in oil and gas extraction from the Russian shelf seas,” Mallett said. But the research revealed much greater annual variability in ice thickness than estimated before. “Knowing the thickness of the ice is pretty critical to planning those activities, so the enhanced variability is generally bad news for those planning to work in the Arctic,” he said.
The Soviet-era data was hard won, Mallett said. “They sent these brave guys out and they sat on these drifting stations and floated around the Arctic, sometimes for years at a time, measuring the snow depth.” But the Intergovernmental Panel on Climate Change identified the lack of more recent data as a key knowledge gap in 2019.
Sea ice thickness is calculated from satellite radar data that measures how high the ice sits above the sea surface. Snow on top of the ice is invisible to the radar signals but it weighs the ice down, so it is critical to know the depth of snow.
“Sea ice has begun forming later and later in the year, so the snow on top has less time to accumulate,” said Mallett. “Our calculations account for this declining snow depth for the first time.” The research is published in the journal The Cryosphere.
“We are still learning about the changes to the Arctic environment, and one of the big unknowns – or less well-knowns – is snow cover,” said Walt Meier, at the US National Snow and Ice Data Center, and not involved in the new research. “The approach in the study is a significant improvement over older methods, and the results fit with other changes we’re seeing with Arctic sea ice, including earlier melt onset, lower summer ice cover, and later freeze-up.”
Prof Julienne Stroeve, at UCL, said: “There are [still] a number of uncertainties but we believe our new calculations are a major step forward. We hope this work can be used to improve climate models that forecast the effects of long-term climate change in the Arctic – a region that is warming at three times the global rate and whose ice is essential for keeping the planet cool.”
by Maja Sojtaric, UiT The Arctic University of Norway
They are diligently stoking thousands of bonfires on the ground close to their crops, but the French winemakers are fighting a losing battle. An above-average warm spell at the end of March has been followed by days of extreme frost, destroying the vines with losses amounting to 90 percent above average. The image of the struggle may well be the most depressingly beautiful illustration of the complexities and unpredictability of global climate warming. It is also an agricultural disaster from Bordeaux to Champagne.https://e1ac7464d9e81ce2033a0fae7f811a32.safeframe.googlesyndication.com/safeframe/1-0-38/html/container.html
It is the loss of the Arctic sea-ice due to climate warming that has, somewhat paradoxically, been implicated with severe cold and snowy mid-latitude winters.
“Climate change doesn’t always manifest in the most obvious ways. It’s easy to extrapolate models to show that winters are getting warmer and to forecast a virtually snow-free future in Europe, but our most recent study shows that is too simplistic. We should beware of making broad sweeping statements about the impacts of climate change.” Says professor Alun Hubbard from CAGE Center for Arctic Gas Hydrate, Environment and Climate at UiT The Arctic University of Norway.
Melting Arctic sea ice supplied 88% of the fresh snow
Hubbard is the co-author of a study in Nature Geoscience examining this counter-intuitive climatic paradox: A 50% reduction in Arctic sea-ice cover has increased open-water and winter evaporation to fuel more extreme snowfall further south across Europe.
The study, led by Dr. Hanna Bailey at the University of Oulu, Finland, has more specifically found that the long-term decline of Arctic sea-ice since the late 1970s had a direct connection to one specific weather event: “Beast from the East”—the February snowfall that brought large parts of the European continent to a halt in 2018, causing £1bn a day in losses.
Researchers discovered that atmospheric vapor traveling south from the Arctic carried a unique geochemical fingerprint, revealing that its source was the warm, open-water surface of the Barents Sea, part of the Arctic Ocean between Norway, Russia, and Svalbard. They found that during the “Beast from the East,” open-water conditions in the Barents Sea supplied up to 88% of the corresponding fresh snow that fell over Europe.
Climate warming is lifting the lid off the Arctic Ocean
“What we’re finding is that sea-ice is effectively a lid on the ocean. And with its long-term reduction across the Arctic, we’re seeing increasing amounts of moisture enter the atmosphere during winter, which directly impacts our weather further south, causing extreme heavy snowfalls. It might seem counter-intuitive, but nature is complex and what happens in the Arctic doesn’t stay in the Arctic.” says Bailey.
When analyzing the long-term trends from 1979 onwards, researchers found that for every square meter of winter sea-ice lost from the Barents Sea, there was a corresponding 70 kg increase in the evaporation, moisture, and snow falling over Europe.
Their findings indicate that within the next 60 years, a predicted ice-free Barents Sea will likely become a significant source of increased winter precipitation—be it rain or snow—for Europe.
“This study illustrates that the abrupt changes being witnessed across the Arctic now, really are affecting the entire planet,” says professor Hubbard.
(CNN)Russia is amassing unprecedented military might in the Arctic and testing its newest weapons in a region freshly ice-free due to the climate emergency, in a bid to secure its northern coast and open up a key shipping route from Asia to Europe.Weapons experts and Western officials have expressed particular concern about one Russian ‘super-weapon,’ the Poseidon 2M39 torpedo. Development of the torpedo is moving fast with Russian President Vladimir Putin requesting an update on a “key stage” of the tests in February from his defense minister Sergei Shoigu, with further tests planned this year, according to multiple reports in state media.
Melting permafrost offers opportunities but poses calamitous risks
An LNG tanker successfully sailed to Asia via the Arctic Ocean early this year, the first time the journey has been managed in winter. (Kyodo photo/courtesy of Sovcomflot)KO SAKAI, Nikkei senior staff writerMarch 14, 2021 09:56 JST
TOKYO — On Feb. 19, a Russian icebreaker that transports liquefied natural gas arrived at Sabetta, an LNG loading port in the far north of Siberia. The ship had sailed through the ice-covered Arctic Ocean on its way to and back from China’s Jiangsu Province.
The journey is noteworthy because the Arctic Sea route that the ship took is usually only navigable from July to November, when the sea ice is thin.
It was the first time for a ship to successfully navigate the Arctic Sea route to Asia in the dead of winter.
Japanese companies took note. JGC Holdings has built an LNG plant near the port, to and from which Mitsui O.S.K. Lines partially handles transportation. Trading house Mitsui & Co. and other parties have invested in the second phase of the LNG project, which is to be completed around 2023. Once a year-round shipping route is established, transportation time between Russia and Japan will be greatly reduced.
Global warming is something of a boon for Russia, where 55% to 65% of the country is covered in permafrost. It is estimated that 60% of the country’s oil and 90% of its natural gas, as well as deposits of nonferrous metals and gold, lie under this thawing part of the planet.
President Vladimir Putin once shrugged off the perils of global warming, saying, “an increase of two or three degrees wouldn’t be so bad for a northern country like Russia. We could spend less on fur coats, and the grain harvest would go up.”
That was at least partially prophetic. According to Russia’s Federal State Statistics Service, grain production in 2020 was up 9.7% from the previous year, the second highest level after 2017. The amount of land under cultivation is also increasing.
But those shrugged-off perils are beginning to overshadow the bumper harvests.
In the Republic of Sakha in far eastern Siberia, the temperature is minus 50 C, yet white smoke rises from the snow-covered ground. In January, local media released an amazing image of a peat fire in the ground under the snow.
Roughly 140,000 sq. km of Russia, about the size of Greece, was lost to fire in 2020. Most of that was in once-frozen areas. When covered with snow in winter, the fires seem to be extinguished. However, the peat in the ground continues to smolder, and in summer it ignites on the surface. They’re being called zombie fires and are believed to be caused by global warming.
There are concerns that the zombies will rage again this year.
Peat fires emit large amounts of carbon dioxide. A record 244 million tons of CO2 equivalents were released by fires near the Arctic Circle, mainly in Russia, in the 12 months through last August, according to the British journal Nature. That is 35% more than a year earlier and equal to 21% of Japan’s total emissions in 2017.
In Siberia, plants and other organisms that have been decomposing for more than 10,000 years are trapped in the soil as CO2 and methane gas. These gases are released by fires and other events, further accelerating global warming. The world’s permafrost zones are thought to contain twice the amount of carbon that is in the atmosphere.The Yamal Peninsula in the Russian Arctic in summer 2020. Seventeen of these holes have been discovered since 2014. (Kyodo photo/courtesy of Russian researchers)
There is another phenomenon that illustrates the seriousness of the situation.
Last summer a craterlike hole with a diameter of 20 meters and depth of 30 meters was discovered in the permafrost zone of northwestern Siberia. It is the 17th such hole to be discovered since 2014. The working hypothesis is that the craters are the result of explosions of accumulated methane gas in the thawing permafrost. The blasts are able to blow away frozen soil that had been contained by ice.
This might be fine so long as no one is living in these locations. But in May 2020, a fuel tank at a power plant on the outskirts of the city of Norilsk in central Siberia collapsed, spilling diesel fuel into a nearby river. It caused such serious environmental damage that Putin declared a state of emergency.
The operating company concluded that the collapse occurred because the ground loosened as the permafrost thawed. It has been reported that one-fifth of the infrastructure in the frozen zone, including oil and gas facilities as well as railroads, will be affected by 2050.
In 2016, western Siberia experienced a different kind of crisis, an anthrax outbreak. One boy and over 2,000 reindeer died. The source of the bacterial infections was the melted corpse of a reindeer that had been frozen for more than 75 years. Some scientists have warned of the possibility of more dormant pathogens reactivating.
Russia ratified the Paris Agreement in September 2019. The base year for reducing greenhouse gas emissions is 1990, just before the collapse of the Soviet Union. Since its emissions have declined rapidly since then, Russia has already met its short-term target.
Although it was supposed to be a global warming “winner,” Russia has become an unexpected climate change victim.
The anomalies in Siberia are a wake-up call from Mother Earth. It is time for all of humanity to listen, and for all of us to pool our collective wisdom to address this problem.
Moscow — A Russian natural gas tanker has completed an experimental round trip along the Northern Sea Route — the first time the path across the Arctic has been forged at this time of year. The voyage by the Christophe de Margerie tanker through the ice is the latest visual indicator of climate change in the delicate region.
The deepest ice encountered by the ships was about 5 feet thick. The vessels encountered no multi-year buildup of old ice on the route, however, and meteorologist and journalist Eric Holthaus called that a clear indicator of “a climate emergency.”
Last May, the Christophe de Margerie became the first large-capacity cargo vessel to complete an eastbound transit of the Northern Sea Route, two months earlier in the year than the journey traditionally has been made.
“As a result of the early Northern Sea Route (NSR) voyage completed by Christophe de Margerie in May 2020, as well as the current NSR voyage, the navigation in the Eastern part of the Arctic was practically doubled,” Sovcomflot CEO Igor Tonkovidov said earlier this month. He noted that for decades the transit route along that segment of the NSR had typically remained closed by ice from November until July.
Novatek, the company that operates the LNG gas plant in Sabetta, plans to continue experimental voyages eastward along the Northern Sea Route, with the next one scheduled this spring, the daily Russian business newspaper Kommersant quoted the company’s boss as saying.
Last year, Russia moved almost 33 million tons of cargo along the Northern Sea Route, including over 18 million tons of LNG. Cargo traffic along the NSR has grown almost fivefold in the past five years alone.
“The route can handle a lot more than that,” Russian Deputy Prime Minister Yury Trutnev said during a government meeting last week. He said that according to a decree issued by President Vladimir Putin, cargo traffic along the NSR should rise to 80 million tons per year by 2024.
“One way that target can be achieved is by expanding the period of Arctic navigation,” Trutnev said.
Estimates of ‘just’ 90 centimeters sea level rise by 2100 ignore Antarctica’s slower but hefty contribution, warns oceanographer John EnglanderShare in FacebookShare in TwitterSend in e-mailSend in e-mailZen ReadPrint article
Glacier on west Greenland in August 2007, as it bends in its normal descent to the sea. Due to warming the melting glacier has retreated far inlandCredit: John EnglanderRuth SchusterGet email notification for articles from Ruth SchusterFollowPublished at 23:48
The vast ice sheet on Greenland has become unstable and technology isn’t storming to the rescue. The world is not on a trajectory to “curb” global warming at 1.5 degrees Celsius – we’re almost there already. “Everybody is asleep. It’s like the Titanic,” wails sea level rise guru John Englander, an oceanographer and author who has made it his life’s mission to shake the world awake before it’s too late.
Too late for what? To secure coastlines all over the world ahead of the rising sea, which is pushing coastlines farther inland. To protect property values, to strategize and reorganize economic priorities, to move seaside nuclear reactors, you name it. Life as we know it.
Part of the reason for the global somnolescence is that scientific reports by nature err on the side of caution. Thus, the current sea level rise estimates for 2050 or 2100 (which distract from the fact that sea level rise will continue afterward) are typically conservative, which in this case means they understate the real rise. It’s also considered rude to conclude that the world is careening toward hell in a handbasket.- Advertisment –
But the world is not on a minimalist trajectory. It is not heading for a “mere” 40-centimeter (16-inch) increase by 2100 based on the optimistic scenario, which is losing credence. The official (UN-IPCC) high end of forecasts is around 90 centimeters by 2100 – but even that is too optimistic in Englander’s view, as he warned in a joint paper with other academics in December: “Twenty-first century sea level rise could exceed IPCC projections for strong-warming futures.”
Sea level rise by 2100 could be 2 meters. It could be 3, or 4 meters, he says. The only thing we know is that we don’t know: the situation is fluid, you should excuse the expression. And we know that a lot of the water will come from Greenland.
To warn the general population, however, Englander feels science’s kid gloves are inappropriate at this point. Mounting evidence indicates climate change is accelerating and creating vicious circles that quicken it even more. The destabilization of Greenland’s ice sheet is a case in point.
It is hard to reconcile reports of its accelerated melting and destabilization with estimates that it will, nonetheless, take maybe five to six centuries for all Greenland’s ice to melt. Englander explains this seeming incongruity.
“I’ve been there several times, leading expeditions,” he tells Haaretz. “It’s hard to comprehend how vast Greenland is. It’s 2,500 kilometers north to south and about 1,000 kilometers east to west, literally from east of the Mississippi in the U.S., and from Maine to Florida” – i.e., nearly 2.2 million square kilometers.- Advertisment –
In Middle Eastern terms, Greenland is about the size of Saudi Arabia. (Israel is about 22,000 square kilometers in area – about twice the size of B-15, the biggest-ever iceberg caught on camera, which calved off the Ross Ice Shelf. )https://www.youtube.com/embed/lBfzFt_kgNU?start=0&controls=1&loop=0&modestbranding=1&rel=1&autoplay=false&enablejsapi=1&mute=undefined
Greenland is covered by a layer of ice 1 to 3 kilometers thick; if it all melts, it will raise global sea levels by over 7 meters. No one thinks that can happen quickly. It will take centuries, at least. “The question is what will happen by 2050 and 2100,” Englander drives home the point.
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Asked if the Greenlandic ice sheet’s recently reported destabilization could change his vague expectation that the melt should take centuries, Englander offers the only answer he can: maybe. Which is all the more reason to wake up.- Advertisment –
Sea level rise cannot be stopped
Even if carbon dioxide emissions were to screen to a halt today, even if cows were to start farting flowers instead of methane, even if every car were to suddenly morph into a tree, further sea level rise is inevitable. Like the Titanic, its direction cannot be diverted anymore, though its momentum might be influenced.
It is time to glance again at John Englander’s famous graph of historic correlations between atmospheric carbon dioxide levels, global mean temperatures, and sea level over the last 400,000 years. The graph shows exactly what the problem is:
Atmospheric carbon dioxide has risen to levels last seen millions of years ago, approximately speaking (neither Donald Trump nor the coronavirus changed the trajectory in any meaningful sense). Atmospheric carbon dioxide concentrations and temperature are correlated: if the one rises, so does the other. The higher the CO2, the higher the global mean temperature – at a lag. Again: at a lag. Temperature has yet to proportionately react to the increase in carbon dioxide levels.
Yes, after CO2 rises, temperature will too – but how long the reaction will take depends on a practically infinite array of parameters, so it cannot be predicted with any meaningful accuracy. All we can say is it will happen, and the fact that the globe has experienced year after year of “record heat” is just the start. Oceans, being vast and dense and saline, take longer to react than the air or shallow lakes, but as the air warms, so does their surface and then their depths. The Arctic has been among the worst affected – there are days parts of it are hotter than in Tel Aviv.
Apropos of which, forecasting the future of Israel’s coast is tricky.
“The coastline has moved kilometers inland over the last 50 years,” says Dr. (emeritus) John K. Hall of the Geological Survey of Israel, adding that this conundrum tends to be met with massive denial. “The beaches are eroding, the cliffs are coming down,” he adds. At sea rise levels of 20 to 30 centimeters, it is difficult to draw lines with any accuracy, to say which neighborhoods will be affected and which spared – but the key issue is the likelihood of increasingly violent storms smashing into the beaches and cliffs. “If sea levels come up, storms will beat the hell out of the coast,” Hall predicts.
Anyway, there is a growing unease in global scientific circles about simultaneously warning and reassuring the public. More and more scientists are warning that sea level will rise faster “than previously thought.” Which means what?
The Greenland ice sheet alone locks up 7 meters of sea level rise, which is bad enough, but Antarctica locks up 65 meters more, Englander explains. All the other glaciers in the world add just 1 more meter. “Looking at glaciers from Mount Kilimanjaro [in Kenya] to the Alps, it’s pocket change” he says.
Ergo: the Arctic island of Greenland and southern continent of Antarctica contain about 98 percent of the ice on land, by volume. Yet modelers have been ignoring Antarctica’s contribution.
This is why? For one thing, because the dynamics and precise timing of Antarctica’s melting ice remain profoundly unclear. As we said, scientists tend to err on the side of caution, lest they be perceived as a pack of yowling Cassandras scorned by policymakers. If you stand on a soapbox shrieking “The end is nigh,” precious few will listen even as avenging angels begin to arrive.
But the result is that projections of half a meter to just-under-a-meter of sea level rise by the century’s end don’t factor in Antarctica, nor do they factor in Greenland’s destabilization, Englander explains.
That is bound to end about as well as the Euripides play performed in 408 B.C.E., where the actor Hegelochus meant to say, “After the storm I see again a calm sea,” but wound up saying, “After the storm I see again a weasel.” Well, 2,500 years belatedly, the unfortunate thespian may have had a point. Those are not calm seas on our horizon.
The Greenlandic irony
What does “Greenland has destabilized” even mean? That parts of the ice sheet and major glaciers are already exhibiting sudden break up and collapse. In 2012, the documentary “Chasing Ice” captured one huge collapse using time-lapse cameras. Meanwhile, Greenland is already the chief contributor to sea level rise today, and it has started to dawn on coastal residents and insurance companies and the like that “something” will have to be done.
Part of Englander’s book due out on April 6, “Moving to Higher Ground” (The Science Bookshelf), discusses exactly these conundrums.
Why is it only an issue now? The science of climate change has been around for decades. Why is anybody still buying a beachside home?
Englander blames a failure of imagination. At the height of the Ice Age, the average sea level was 120 meters lower than it is now. As the latest Ice Age waned and the ice sheets melted, sea levels gradually rose – sometimes more abruptly than at other times. But none of that happened during recorded history.
Civilization as we could recognize it – a gradual transition from hunting-gathering to a settled lifestyle – seems to have begun around 12,000 years ago, some places earlier, some places later, well after the Last Glacial Maximum 22,000 years ago. People adore living by the coast and always have. Even Neanderthals are thought to have frolicked in the water and dived for shellfish. And the first villages on low-lying shoreland were indeed inundated. Israeli archaeologists, for example, have found the remains of Neolithic villages off today’s coast, under the waves of the Mediterranean.
But for the last 7,000 or 8,000 years, sea levels have been stable, near present-day heights, and we are not capable of imagining the situation otherwise, Englander postulates.
Sea levels have been creeping up since the industrial revolution began and some cities have noticed – think of Miami and its sunny-day floods. But that is why we simply cannot fathom what a meter or two even mean. It’s beyond our scope of experience.
The last time sea level was above present-day levels was 122,000 years ago, when it was some 7 meters above present, he explains.
“Even at the accelerated warming rate, most people don’t think we’ll get more than a meter out of sea level rise from Greenland this century. But a meter of global sea level rise would be devastating, flooding literally thousands of coastal communities,” he points out the obvious.
Three of the biggest cities in the world are in acute danger: Shanghai, Mumbai and Jakarta, and so are hundreds more from Alexandria to Boston to London.
Ironically, Greenland’s own coastlines are probably safe. This is because as its ice cover melts, the land is rising, as land does when an enormous weight is lifted. It is the obverse of the situation in Jakarta, where the land is sinking because of groundwater depletion, the heavy buildings and sea level rise. Never mind 2100: the city is expected to be 95 percent underwater by 2050.
“The human instinct is to be optimistic, [to hope] technology will come to the rescue. But it doesn’t make sense in this context,” Englander sums up. “The oceans have been warmed almost a degree already and we’re going to warm them 2 degrees more. The ice is going to melt.”
Frozen Greenland is on track to become significantly less frozen before the 21st century is over. By 2055, winter snowfall on the Greenland Ice Sheet will no longer be enough to replenish the ice that Greenland loses each summer, new research finds.
Rising global temperatures are driving this dramatic change. If Earth continues to heat up at its present pace, average global temperatures should climb by nearly 5 degrees Fahrenheit (2.7 degrees Celsius) by 2055. Regional averages in Greenland become even hotter, rising by about 8 F (4.5 C), scientists reported in a new study.
Under those conditions, Greenland’s annual ice loss could increase sea levels by up to 5 inches (13 centimeters) by 2100 — unless drastic steps are taken, starting now, to curb greenhouse gas emissions and slow global warming trends.
Ice sheets are any thick masses of ice that cover more than 20,000 square miles (50,000 square kilometers) of land, and they grow their icy layers from snow that builds up over thousands of years, according to the National Snow and Ice Data Center (NSIDC). During the last ice age (around 115,000 to 11,700 years ago), ice sheets blanketed much of North America and Scandinavia. But today, only two ice sheets remain — in Greenland and in Antarctica — holding around 99% of Earth’s freshwater reserves, NSIDC says.
Ice sheets aren’t static — their own weight pushes them slowly toward the ocean, where they discharge ice and meltwater from ice shelves, streams and glaciers. An ice sheet can remain stable only so long as its lost ice is replenished seasonally by winter snowfall.
The Greenland Ice Sheet is roughly three times the size of Texas, measuring approximately 656,000 square miles (1.7 million square km), according to NSIDC. If all of Greenland’s ice were to melt at once, sea levels would rise by about 20 feet (6 meters). While that catastrophic scenario is unlikely to happen anytime soon, Greenland has been steadily losing ice for decades, at a rate of about 500 gigatons per year since 1999, another study published in August 2020 found.
Those scientists said that Greenland was already losing more ice than it gained every winter. Their models factored in ice loss from iceberg calving, which can be substantial; a massive iceberg that separated and drifted alarmingly close to a Greenland village in 2018 was thought to weigh more than 12 million tons (11 million metric tons), Live Science previously reported.
However, the processes that drive icebergs to separate from the ice sheet are complex and unpredictable, said Brice Noël, lead author of the new study and a researcher with the Institute for Marine and Atmospheric research (IMAU) at Utrecht University in the Netherlands. For the new study, the researchers analyzed the Greenland Ice Sheet’s surface to determine when melt would surpass snowfall, Noël told Live Science in an email.
“We explore the sensitivity of the Greenland Ice Sheet mass loss to atmospheric warming using a much higher resolution climate model — 1 km — compared to previous work (20 to 100 km),” Noël said. “Higher spatial resolution means that we can now better capture the high mass loss rates of small outlet glaciers;” this source of melt runoff was previously excluded from models, but contributes significantly to the total mass of ice lost, he explained.
“As a result, we can more accurately project the future evolution of the Greenland Ice Sheet mass loss and its contribution to sea-level rise,” Noël said.
Stability of the ice sheet began to slip after the 1990s, as atmospheric warming boosted meltwater runoff during warm summer months, according to the study. Models showed that most of the runoff was produced at the margins of the ice sheet, in a narrow band called the ablation zone. As Earth warms, it melts the ablation zone’s protective layer of tightly compressed snow. Once this layer is gone, the ice underneath — which is much less reflective than the bright snow — absorbs more sunlight, leading to more melt.
“The accelerating exposure of bare ice amplifies the runoff production, and thus the surface mass loss,” Noël said.
In a scenario where humans don’t lower greenhouse gas emissions and present warming continues, ice loss in Greenland will cross a new threshold — in which the ice sheet gets smaller each year — within just a few decades, according to the study. And that’s a conservative estimate; that threshold could be crossed even earlier, depending on how much additional ice is lost annually from calving icebergs, the authors reported.
It could then take thousands of years for the ice sheet to melt completely, but saving Greenland’s ice from disappearing would require halting or reversing global warming sooner rather than later — “during this century,” Noël said.
That’s why the dark zone is so worrisome. During the summer months, part of the western section of the ice sheet turns from brilliant white to inky gray as algae bloom across the surface. Since 2000, these blooms have gotten bigger, causing the dark zone to expand, according to a statement by the researchers.
The darker color of the ice reduces its albedo — the amount of sunlight it reflects back to space — and causes the ice sheet to absorb more heat. However, until now, what triggers these algal blooms has remained a mystery.
“We see a lot of variability in the blooms that form on the ice-sheet surface,” said Jenine McCutcheon, a microbiologist at the University of Waterloo in Ontario and lead author of the new study describing the findings. “We wanted to better understand what causes their growth,” she told Live Science.
Understanding the algal blooms
During the Arctic’s sunless winter months, the ice algae — primarily made up of Ancylonema nordenskioeldii and species in the Mesotaenium genus — remain in a dormant state deep within the ice. During spring, as the ice melts, these algae slowly migrate to the surface. When they reach the surface, the Arctic summer provides 24-hour sunlight for photosynthesis and growth. The algae are normally green, but when exposed to constant sunlight, they create dark-colored sunscreens to protect themselves from damaging ultraviolet rays. This is what darkens the ice and, ironically, causes it to absorb more sunlight.(Image credit: Jim McQuaid)
But sunlight alone didn’t seem enough to cause the expansive blooms the researchers were seeing.
After the researchers analyzed samples they collected from the surface, “it became clear phosphorus was the most important nutrient to the algae,” study co-author Jim McQuaid, a climate scientist at the University of Leeds in England, told Live Science. “We then found that it was originating locally.”
In Greenland, the phosphorus comes from hydroxylapatite — a phosphate mineral that also contains calcium, oxygen and hydrogen — that gets blown across the ice as dust from exposed rocky outcrops.
“As the atmosphere gets warmer due to climate change, the exposed rock becomes drier and winds get stronger,” McQuaid said. “This means more dust is transported across the ice.”
Melting ice in the area also uncovers more hydroxylapatite-rich rocks, thus increasing the available phosphorus. So the algal blooms are part of a positive feedback loop: The increased ice melting leads to a higher phosphorus input, which spurs the algal growth that, in turn, further increases the ice melting.
“This type of thing will continue to happen in the future; there’s no doubt in my mind,” McQuaid said, referring to the accelerated melting.RELATED CONTENT
However, now that scientists fully understand the dark zone phenomenon, they can more accurately predict how fast the Greenland ice sheet will melt.
“If we can measure the amount of phosphorus that’s in the environment, it may be possible to translate that to an estimate of algal growth and allow us to better monitor the rate of ice melting,” McCutcheon said.