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A big chunk of ice has broken away from the Greenland ice sheet and the Arctic’s largest remaining ice shelf- called 79N, or Nioghalvfjerdsfjorden- in north-east Greenland. 

The piece that has broken off covers about 110 sq km. The Nioghalvfjerdsfjorden is roughly 1 600 sq km and is the floating front end of the northeast Greenland Ice Sheet, where it flows into the ocean. The glacier splits into two pieces, with a small offshoot to the north; it is this offshoot, called Spalte Glacier, that has disintegrated. 

The loss is further evidence of the advancing climate crisis and the changes happening in the region and to the Greenland Ice Sheet. According to Dr Jenny Turton, the atmosphere in the region has warmed by about 3 degrees Celsius since 1980. 

Satellite images show that these higher air temperatures in the region can be seen in the number of melt ponds that sit on top of the shelf ice. This water is problematic for ice platforms because if it fills crevasses, it can help to open them up. The water will push down on the fissures, moving them to the base of the shelf in a process known as hydrofracturing, which weakens the ice shelf. Warmer sea temperatures in the region mean that ice is probably being melted from beneath as well. 

greenland ice sheet n79

Professor Jason Box from the Geological Survey of Denmark and Greenland, says, “79N became the ‘largest remaining Arctic ice shelf’ only fairly recently, after the Petermann Glacier in northwest Greenland lost a lot of area in 2010 and 2012. What makes 79N so important is the way it’s attached to the interior ice sheet, and that means that one day- if the climate warms as we expect- this region will probably become one of the major centres of action for the deglaciation of Greenland.” He believes that 79N will likely disintegrate from the middle, but says that this could happen in anywhere from 10 to 20 years. 

July saw another large ice shelf structure in the Arctic lose a large amount of area; the last fully intact ice shelf in Canada in the Arctic collapsed, losing about 40% of its area over a two-day period. The ice shelf is now 106 sq km in size, after 80 sq km broke off from the Milne Ice Shelf. The Milne was the largest intact remnant from a wider shelf feature that covered 8 600 sq km at the start of the 20th century.

Further, the Greenland ice sheet lost a record amount of ice in 2019: an average of a million tons per minute throughout the year.

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The climate crisis is heating the Arctic region at double the rate than at lower latitudes, and the Greenland ice sheet will be one of the biggest contributors to sea level rise, which is already affecting coastline cities around the world.

Featured image by: Flickr

According to satellite data, the Greenland ice sheet lost a record amount of ice in 2019: an average of a million tons per minute throughout the year. The climate crisis is heating the Arctic region at double the rate than at lower latitudes, and the Greenland ice sheet will be one of the biggest contributors to sea level rise, which is already affecting coastline cities around the world.

Published in the journal Communications Earth & Environment, the research used data from NASA’s Grace satellites, which take gravity measurement and essentially weigh the mass of ice in Greenland. The researchers say that the scale of the 2019 loss was likely to be the biggest in centuries. 

The Greenland ice sheet shrank by 600 billion tons in 2019. This, according to satellite data that has been collected since 2003, was more than double the annual average since then of 255 billion tons. Weather data and computer models allow for losses to be calculated back to 1948. Almost 96% of the ice sheet underwent melting at some point in 2019, compared with an average of 64% between 1981 and 2010. The researchers add that of record melt years, the top five has happened in the last 10 years. 

The researchers attributed this massive ice loss in 2019 to “blocking patterns” of weather that kept warm air over Greenland for longer, occurrences which are becoming more frequent as the climate crisis accelerates. This pattern also caused low snowfall, which means that little ice was added to the sheet. 

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However, the researchers found that in 2017 and 2018, there was unusually low ice loss, as this block pattern was reversed. This led to cold, snowy conditions over Greenland. However, they stress that ice was still lost from the ice sheet, and that cold years do not make up for the hot ones. 

Ingo Sasgen of the Alfred Wegener Institute in Bremerhaven, Germany, who led the analysis, says, “2019 was really shocking and depressing in terms of the numbers. But it’s also not very surprising, because we had other strong melt years in 2010 and 2012, and  expect we will see more and more.” 

Sasgen expresses further concern about feedback loop mechanisms that increase ice loss, like meltwater weakening the ice sheet and exacerbating its fall into the ocean. Warmer temperatures also melt the white snow on top of the sheet, revealing darker ice below, which absorbs more of the sun’s heat. 

If the entire Greenland ice sheet melts, sea level would rise by six metres. However, the researchers say that cutting carbon emissions will reduce the sea level rise from the ice sheet, which will allow those living near coasts to move away. 

Secondly, as glaciers retreat, they lose contact with warmer ocean waters and therefore melt less, and the melting of the sheet with warm air will take centuries, during which time the rise in global temperatures may be reversed. 

Featured image by: NASA Handout/ EPA

The ice sheet covering Greenland experienced dramatic melting in the summer of 2019, researchers have confirmed, in a study that reveals the loss was largely down to atmospheric circulation patterns that have become more frequent in the region, a phenomenon that is not being incorporated into climate models and suggests that scientists are underestimating the melt rates of the Greenland ice sheet.

Greenland Ice Sheet Melting: Facts

The Greenland ice sheet melted at a near record rate in 2019 and much faster than the average of previous decades. The sheet lost about 560 gigatons of water last year, which would contribute about 1.5mm of sea-level rise according to the study published in The Cryosphere, a scientific journal. The surface mass balance, the amount of ice the sheet gained from rain and snowfall minus the amount lost through meltwater run-off and evaporation, was 54 gigatons a year- about 320 gigatons lower than the average across earlier decades, and the greatest such drop recorded.

Marco Tedesco, a research professor at Columbia University’s Lamont- Doherty Earth Observatory and leader of the study, says, “We’re destroying ice in decades that was built over thousands of years. What we do here has huge implications for everywhere else in the world.”

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The team used satellite data, climate models and global weather patterns to investigate the melting of the surface of the ice sheet in 2019. Among their findings, the team report that almost 96% of the ice sheet experienced meeting at some time in 2019, compared with an average of just over 64% between 1981 and 2010.

The high pressure conditions lasted for 63 of the 92 summer days in 2019, compared with an average of 28 days between 1981 and 2010. A similar situation was seen in 2012, a record year for melting of the ice sheet. Levels of snowfall and reflection of sunlight, as well as cloudiness and absorption of sunlight were all influenced by the persistent high pressure zone over the sheet last summer. 

These anti-cyclonic conditions blocked the formation of clouds over southern Greenland, causing unfiltered sunlight to melt the ice sheet surface. Fewer clouds also meant less snow, which exposed darkened, soot-covered ice which absorbs heat instead of reflecting it. The study showed that conditions were different, but no better in the northern and western parts of Greenland, due to warm, moist air pulled up from lower latitudes. 

Tedesco says, “These atmospheric conditions are becoming more and more frequent over the past few decades.” 

Crucially, the team of researchers says that the climate models of the Intergovernmental Panel on Climate Change (IPCC) have not incorporated these unusual conditions into climate models. If these high pressure zones persist, future melting could be twice as high as currently predicted, which would have catastrophic consequences for sea-level rise. 

Over the last few decades, Greenland contributed between 20 and 25% of global sea level rise. If carbon emissions continue to increase, this share could rise to around 40% by 2100, not taking into account the ice melt in Antarctica, the largest ice sheet on Earth. 

Greenland’s ice sheet covers 80% of the island and is currently predicted to raise global sea levels by up to 7 metres if it melts entirely. 

Average temperatures in the Arctic region have risen two degrees Celsius since the mid-19th century, twice the global average.   

Featured image by: Kitty Terwolbeck

A new study shows that the Arctic will have ice-free summers by 2050, threatening the Arctic ecosystem with devastating consequences and escalating sea-level rise. 

Published in Geophysical Research Letters, the study involved 21 research institutes from around the world, where researchers analysed recent results from 40 different climate models. Using these models, the researchers assessed the progression of Arctic sea-ice cover in scenarios with high CO2 emissions and little climate protection. In these simulations, summer Arctic sea-ice disappeared quickly.

An Ice-Free Arctic

In most of these simulations, the Arctic sea-ice was reduced to less than a million sq kms- a level that is ‘practically sea-ice free’, according to the researchers- in September for the first time before 2050. 

Surprisingly, researchers also found that ice disappeared in some simulations where CO2 emissions were rapidly reduced, but that ice-free years would occur ‘only occasionally’. With higher emissions, the Arctic Ocean will become ice-free in most years.

Bruno Tremblay, Associate Professor in the Department of Atmospheric and Oceanic Sciences at McGill University and co-author of the report, says, “While the Arctic sea-ice extent is decreasing during this transition to an ice-free Arctic, the year-to-year variability in extent greatly increases, making life more difficult for local populations and ice-dependent species.

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Sadly, there is enough ‘locked in’ global warming that even if carbon emissions are drastically reduced, there will still be a significant melting of sea-ice.

When will the Arctic melt completely?

Dirk Notz, who leads the sea-ice research group at University of Hamburg and coordinated the study, says, “If we reduce global emissions rapidly and substantially, and thus keep global warming below 2 degrees Celsius relative to pre-industrial levels, the Arctic will nevertheless be occasionally ice-free in summers even before 2050. This really surprised us.”

Currently, the North Pole is covered by sea-ice all year. Each summer, the area of sea-ice coverage decreases and grows again in winter. However, as a result of rising temperatures, the area of the Arctic Ocean covered by sea-ice has reduced rapidly over the past few decades. 

This affects the Arctic ecosystem and climate significantly. The sea-ice cover is a hunting ground and habitat for polar bears and seals and keeps the Arctic cool by reflecting sunlight.

The climate crisis is warming the Arctic more than twice as fast as anywhere else on the planet. Seas are now rising an average of 3.2 mm per year globally, and are predicted to climb to a total of 0.2 to 2m by 2100. In the Arctic, the Greenland Ice Sheet poses the greatest risk for sea levels because melting land ice is the main cause of rising sea levels.

This is made all the more concerning considering that last year’s summer triggered the loss of 60 billion tons of ice from Greenland, enough to raise global sea levels by 2.2mm in just two months

The researchers emphasise that humans determine how often the Arctic Ocean will be ice-free in the summers, depending on the future level of emissions. It is vital that countries cooperate on a global scale to lower emissions to avoid catastrophic climate breakdown that will render hundreds of millions of people without homes. 

Earth.Org analysed satellite data to assess the concentration of methane emissions in the Greenland ice sheet (GiS) in July 2019. The GiS covers an area of roughly 1,7million square km; together with Antarctica’s ice sheet, it contains more than 99% of the world’s fresh water. Most of this water is frozen in masses of snow and ice and as greenhouse gases build, the oceans absorb 93% of the excess heat those gases trap. The warming air and water are causing ice sheets to melt at unprecedented rates. 

Besides sea-level rising, the melting of this ice sheet in Greenland has another side-effect- methane emissions, which has rapidly increased in the past decades and more than doubled from pre-industrial times.

Methane, or CH4, has a 20-year Global Warming Potential (GWP) of 84, which means that over a 20-year time period, it’s 84 times more powerful than CO2 at trapping heat in the atmosphere. Methane emissions are temperature-sensitive and could provide significant feedback mechanisms in a changing climate. 

Arctic Methane

The Arctic region is one of the most abundant natural sources of methane. It is estimated that the Arctic permafrost (carbon-rich soils that remain completely frozen for at least two years straight) stores 1 650 gigatonnes of organic carbon, twice the amount of greenhouse gases in the atmosphere. 

As the temperature rises above 0°C, microbes in the permafrost decompose frozen organic matter into methane, an anaerobic biotic process known as methanogenesis. Thawing of the permafrost produces both methane and CO2. A warming climate can induce environmental changes that accelerate this decomposition and release of greenhouse gases. This feedback can accelerate climate change, but the magnitude and timing of greenhouse gas emissions from these regions and their impact on climate change remain unclear. This makes it all the more concerning that ice sheets are currently ignored in global methane budgets and that there is no existing data on the current methane footprint of ice sheets. 

A study conducted by the University of Bristol found that much of the methane produced beneath the ice likely escapes the GiS in large, fast flowing rivers before it can be oxidised to CO2

A study estimated that 6.3 tonnes of methane was transported by meltwater underneath the ice in the summer of 2015. Every summer, the ice sheets melt in Greenland, peaking in June to August and although this is a natural process, global warming is accelerating the rate of melting. Subglacially produced methane is rapidly driven to the ice margin by the efficient drainage system of a subglacial catchment of the GiS. Another study reported a concentration of methane emissions 15 times the background atmospheric concentration in the air expelled with meltwater in West Greenland in 2016. The total amount of methane released with meltwater remains unestimated.

From 1992 to 2018, about half of the ice loss from Greenland was from melting driven by air surface temperatures, which have risen much faster in the Arctic than the global average (more than double), and the rest was from the speeding up of the flow of ice into the sea from glaciers, driven by the warming ocean. 

The Sentinel- 5P satellite captures methane hot spots where methane-saturated fluxes reach the ice margin. 

While many studies place their focus on the West GiS, the satellite images produced from Sentinel- 5P have revealed another bright hot spot on the north, near the North Pole. 

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Satellite Image of Methane Emissions in Greenland

The image above shows the concentration of methane in Greenland in July 2019 according to images taken by Earth.Org from the Sentinel- 5P satellite. The mean methane concentration over Greenland during the month was 1 809.6 ppb (parts per billion), with a local maximum of 1 968.2 ppb. 

The information for the images above is taken from research by the National Snow and Ice Data Center, which Earth.Org has tabulated. The top graph shows the mean daily melting area during melting seasons from 1981 to 2019, and the bottom graph shows the maximum daily melting area during melting seasons from 1981 to 2019. 

Researchers suggest that the microbes in the frozen soil contain methane-oxidising communities, essentially making the tundra a methane sink. The effect of methane digestion increases with temperature, so it is particularly potent in the growing seasons (July- September).

Studies suggest that a longer growing season results in ‘potentially high emissions’ by permafrost systems. This creates a cycle, called a ‘climate change feedback’, whereby global warming causes ice sheets to melt, which releases more methane, which in turn exacerbates global warming. 

Greenland Ice Melt

According to a study conducted in December, Greenland’s ice is melting seven times faster than it did in 1992. From July 30 to August 3, melting occurred across 90% of the continent’s surface, dumping 55 billion tonnes of water over 5 days. On August 1, the GiS lost 12.5 billion tonnes of ice, more than any day since researchers started recording ice loss in 1950. 

Melting seen at this rate was not expected for another 50 years; by the last week of July, melting had reached levels that scientists with the IPCC had projected for the year 2070 in the most pessimistic scenario. 

The region has lost more than 4.2 trillion tonnes of ice in the last 25 years, which has raised global sea levels over 1cm. The rate of ice loss has risen from 33 billion tonnes a year in the 1990s to 254 billion tonnes a year in the last decade. The IPCC has estimated that global sea levels could rise by 60cm by 2100, putting 360 million people at risk of annual coastal flooding. However, this new study shows that if the current melt rate continues, Greenland will raise sea levels nearly 7cm more than the IPCC’s prediction by 2100, putting an additional 40 million people at risk. 

One of the keys to reducing methane emissions in Greenland, and certainly the rest of the world, is cutting the use of fossil fuels. Additionally, there is too much uncertainty surrounding the impacts of these environments on the planet and they should be considered in the Earth’s methane budget so as to allow researchers and policy makers to collaborate to mitigate and manage the effects of these emissions. 

This is the second of two parts in an Earth.Org investigation of methane emissions in the polar regions. See December 20th’s article, ‘Methane Emissions in the Arctic Could Amplify Global Warming’. 

Featured image by: Christine Zenino

Glaciers and ice sheets currently cover around 10% of the Earth’s surface and are vital for shaping its physical landscape, reflecting intense solar radiation and supplying many people around the world with freshwater. Until recently, however, one characteristic of this environment has remained largely overlooked. What are algae blooms and how are they affecting the landscape?

Algae blooms living on the surface of the south-west coast of the Greenland Ice Sheet (GrIS) are causing darkening of the sheet, leading to increased rates of melting not currently being incorporated into melt rate models.

Glaciers and ice sheets are extremely dynamic ecosystems, capable of hosting abundant and diverse microbial life. Areas of the Earth in which water is found in a solid, frozen form are now termed the Cryosphere, which is considered one of the Earth’s five biospheres. Due to extreme and harsh conditions, particularly in the Arctic and Antarctic, microbial abundance, diversity and activity in these environments have been given little global prominence.  

Microbial life has now been documented in most areas of glaciers and ice sheets, including at the bedrock-ice interface, on the ice surface and inside the ice itself. Most initial research focused on microbial communities living at the bedrock-ice interface due to their influence on nutrient export to fjord and ocean environments. Surface ice environments, comprised of snow packs, bare ice, lakes and streams, have recently begun to take centre stage as microbial communities thriving in these habitats have drastically changed the physical appearance of glaciers and ice sheets worldwide. Areas of high microbial abundance and activity, known as cryoconite holes, have quickly become the primary focus of attention in surface ice environments. Cryoconite is a dark substance now found on most glacier and ice sheet surfaces worldwide, with areas of high abundance described as having the appearance of swiss cheese. 

It wasn’t until 2012 that scientists discovered a habitat other than cryoconite holes: the ice surface itself. A study of the GrIS found that the top two centimetres of the ice surface hosts abundant microbial life, dominated mainly by Streptophyta algae, now termed glacier algae.  

Prior to this finding, satellite imagery revealed a significant annual darkening occurring since 2000 on the surface of the GrIS, on an area about 20-30 km inland and 50 km wide, now known as the ‘Dark Zone’. Many scientists initially attributed this darkening to common light-absorbing particles such as atmospheric dust, black carbon from the burning of fossil fuels, dust melting out of ancient ice and even cryoconite. Cryoconite holes typically cover only 3-6% of the whole GrIS, whereas glacier algae appear to bloom wherever bare ice is present, therefore covering far greater areas.  In fact, a study reported an abundance of up to 85 thousand glacier algae cells per milliliter of melted surface ice collected in the Dark Zone.

Glacier algae have adopted many unique strategies for surviving in this extreme environment, yet one has elevated their global importance. Ice surfaces are subject to intense solar radiation, due to 24 hours of sunlight during the polar summer. As such, glacier algae have developed a dark pigmentation within their cells to help shield them from radiation. Because of this pigmentation and their high abundance in the Dark Zone, several studies have now concluded that pigmented algae have the greatest impact on ice surface darkening compared to any other nonalgal impurity, including black carbon or dust melting out of ancient ice. Yet, at present, algal influence on surface darkening, known as bioalbedo, is not being factored into melt rate models for the GrIS. 

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Pigmented glacier algae, as seen under a microscope. (Source: Yallop et. al, 2012/Nature.com)

The GrIS has experienced a significant increase in net mass loss in the past two decades, increasing from 34 gigatonnes of ice per year during 1992 – 2001 to 215 gigatonnes of ice per year during 2002 – 2011, with surface ice accounting for nearly 68% of that increase since 2009.  As temperatures continue to rise in the Arctic, seasonal snow packs, which form during the winter and melt away in the spring, will retreat earlier, leading to an extended season of bare ice exposure. This will result in more surface ice melt and nutrient and liquid water availability, perfect growing conditions for glacier algae blooms. Furthermore, the burning of fossil fuels releases nutrients necessary for cell growth, such as nitrogen, into the atmosphere, which are transported to surface ice environments that are otherwise nutrient-limited.  This extra abundance of nutrients allows for microbial communities to spend less energy on producing nutrients and more energy on growth.  

It can therefore be expected that these blooms seen on the GrIS, and on glaciers and ice sheets throughout the cryosphere, will continue to escalate leading to further darkening of the sheet and increased melt rates, resulting in increased sea-level rising. 

Featured image by: Christine Zenino

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