The Arctic Ocean could be ice-free sooner than what most of the scientific studies have predicted so far. A new study led by the University of Calgary’s Cryosphere Climate Research Group claims that satellite data for the thickness of seasonal ice (one-year-old ice) have been overestimated by up to 25 per cent. The study attributes this inaccuracy of satellite readings to the saline properties of snow cover on top of the ice.
“The problem is, microwave measurements from satellites don’t penetrate the salty snow very well, so the satellite is not measuring the proper sea ice freeboard and the satellite readings overestimate the thickness of the ice,” says Vishnu Nandan, Geography Eyes High doctoral candidate and lead author of the study.
All this while, all the scientific estimates on sea ice thickness and volume have been made based on the data provided by the European Space Agency’s CryoSat-2 (CS-2) satellite, considering that the satellite can accurately measure the sea ice freeboard, which is the ice we can see above sea level. “But that ice is covered in snow and the snow is salty close to where the sea ice surface is,” adds Nandan.
The study concludes that the “snow cover on sea ice affects the CS-2 radar waves” and it has the potential to misrepresent the sea ice freeboard, leading to ambiguous sea ice thickness estimates”.
Questioning measurements provided over the past decade by the CryoSat-2 means the first ice-free summer in the Arctic Ocean may happen much sooner than between 2040 and 2050 as predicted by previous studies. Previous studies had pointed to shorter sea ice season with total number of ice-covered days declining by seven to 19 days per decade in the last 35 years. In fact, in March 2017, the Arctic Sea ice extent dipped to a record low.
Dispelling inaccuracy in satellite data
To offset the inaccuracy of satellite readings, Nandan and his co-researchers from University of Calgary as well as researchers from Toronto, Germany and France examined the role of saline snow on first-year sea ice (FYI), with respect to its ability to decrease radar penetration depth and its impact on FYI thickness estimates. For this, they combined microwave theory and over 10 years of snow property data in the Canadian Arctic.
Prior to this study, it was believed that the volume of ice has been declining by 17 per cent every decade since 1979. The new research shows that the rate of summer sea ice decline could be slightly faster.
Ice-free summers in the Arctic Ocean “would radically affect global weather patterns and dramatically increase the magnitude and frequency of storm events. It would also dramatically alter the Arctic marine ecosystem, with the added sunlight affecting the Arctic Ocean food web and melting the very ice bed on which animals like polar bears hunt,” says John Yackel, professor of geography, University of Calgary.
The study recommends considering snow salinity in all future estimates on the Arctic seasonal ice freeboard made from satellites.
In 2007, the Intergovernmental Panel on Climate Change (IPCC) had estimated that the Arctic will have an ice-free summer by the end of this century. We might not have to live that long to see that happen as Peter Wadhams of Cambridge University (UK) has predicted ice-free summer in the Arctic in 2016. His prediction is based on projected data from the US National Snow and Ice Data Center (NSIDC).
Predictions based on NSIDC data
According to the provisional satellite data produced by the NSIDC, there was just over 11.1 million sq km of sea ice on June 1 as compared to the 30-year average of 12.7 million sq km The difference of more than 1.5 million sq km is more than four times the size of Germany. When Wadhams predicted ice-free summer in the Arctic, he meant less than one million square kilometers of sea ice in the Arctic Ocean – which means 90 per cent shrinkage in ice cap over a period of three months.
The world had received a rude awakening in 2011 when the NSIDC data revealed that ice caps covered just 4.33 million sq km of the Arctic Ocean in September. A year later, the mid-September reading in 2012 measured 3.4 million sq km. Four years down the line, we are looking at a scenario where less than one million square kilometres of sea ice is a possibility.
Why is 2016 worst so far?
Some climatologists and researchers are sceptical about Wadham’s predictions. However, that doesn’t nullify the fact that all the indications were pointing to a worst summer this year. The Arctic sea ice extent set a record low in March 2016. On March 24, Arctic sea ice extent was recorded at 14.52 million sq km, a record low ever since satellite observations started in 1979.
The sea ice extent is melting faster than at the same time of the year in 2012. Last Year, Down To Earth reported the growing enthusiasm among scientists to understand the reason behind thinning of ice layer and far-reaching consequences on climate change.
This year, fractures in the ice cover became evident in the north of Greenland as early as May. Mark Serreze, the Director of the NSIDC, thinks fractures are "quite unusual" at this time of the year. Satellite images show the fracturing of sea ice is more prominent in the Beaufort Sea, north of Alaska, where the ice is rapidly breaking up. This fracturing, according to Serrezze, is "a sign of much thinner ice in the region that is typically the thickest and most durable".
Another fact that seems to defend Wadham’s arguments is the emergence of “unusually thin and even totally absent” sea ice covers on both the Atlantic and Pacific sides of the Arctic.
Arctic ice loss linked to weather changes in Europe and the US
A team of researchers at Rutgers University has been harping on the concept of “Arctic amplification”. It refers to the enhanced sensitivity of high latitudes to global warming. Declining sea ice is one of the contributing factors to this phenomenon. Extreme weather in Western Europe and large swathes of North America is attributed to Arctic amplification.
According to climatologists, changes in the jet streams, especially polar jet streams, are also linked to global warming. Jet streams are ribbon of strong winds blowing high above in the atmosphere and exerting huge influence on weather patterns. When the jet streams are warmer, their ups and downs become more extreme, bringing different weather to areas unaccustomed to climate variations. They bring prolonged cold weather and snowfall to some places and extended summer with unusually hot conditions to others. It explains the occurrence of massive snowstorms and bone-chilling cold on the east coast of the US and flooding in Britain.
With the warming of the Arctic and the loss of sea ice, scientists have observed that methane – a greenhouse gas – has started to bubble up to the surface at a precariously faster rate. Generally, it lies frozen on the sea bed. One can’t be oblivious to another major concern: having less sea ice would lead to higher absorption of the sun's energy as the surface of the earth gets darker.
Hard times for Arctic species
Species like polar bears, seals and walruses depend on sea ice cover to breed, hunt and rest. The depleting sea ice causes malnutrition in them and their already declining population sees a further southward trend.
According to Andrew Freedman, the Science Editor at Mashable, dwindling sea ice cover has forced walruses to undertake a journey of hundreds of miles for food. That’s precisely why tens of thousands of them are increasingly seen on beaches in Alaska and Russia. They come here in search of rest. The polar bears use sea ice in the Arctic as a hunting ground for seals. However, they are experiencing weight loss in recent years as they have 30 less days every year to hunt on the ice.
NASA study on Arctic regions
According to a new NASA study published on an April 2016 paper in Remote Sensing of Environment, Arctic regions of North America are losing their white patches and getting greener. Almost one-third of the land cover resembles landscapes found in warmer climes. The images captured by Landsat satellites reveal a healthy growth of vegetation on the ground. The researchers are of the opinion that Quebec (Canada), western Alaska other regions became lot greener between 1984 and 2012.
Rising temperatures in the Arctic has made the region conducive for plants to grow and led to the changes in the soils. Grassy tundra is changing to shrubland and shrubs are growing bigger and denser. The images suggested extensive greening in the tundra region of western Alaska, the tundra region of Quebec and Labrador and the northern coast of Canada.
Hence, the rapid loss of Arctic ice is not only spelling disaster for the Arctic species but also scripting a drastic shift in climatic patterns that the world is not yet ready to tackle.
For the Arctic, like the globe as a whole, 2016 has been exceptionally warm. For much of the year, Arctic temperatures have been much higher than normal, and sea ice concentrations have been at record low levels.
The Arctic’s seasonal cycle means that the lowest sea ice concentrations occur in September each year. But while September 2012 had less ice than September 2016, this year the ice coverage has not increased as expected as we moved into the northern winter. As a result, since late October, Arctic sea ice extent has been at record low levels for the time of year.
Late 2016 has produced new record lows for Arctic ice. NSIDC, Author provided
These record low sea ice levels have been associated with exceptionally high temperatures for the Arctic region. November and December (so far) have seen record warm temperatures. At the same time Siberia, and very recently North America, have experienced conditions that are slightly cooler than normal.
Temperatures have been far above normal over vast areas of the Arctic this November and December. Geert Jan van Oldenborgh/KNMI/ERA-Interim, Author provided
Extreme Arctic warmth and low ice coverage affect the migration patterns of marine mammals and have been linked with mass starvation and deaths among reindeer, as well as affecting polar bear habitats.
Given these severe ecological impacts and the potential influence of the Arctic on the climates of North America and Europe, it is important that we try to understand whether and how human-induced climate change has played a role in this event.
Arctic attribution
Our World Weather Attribution group, led by Climate Central and including researchers at the University of Melbourne, the University of Oxford and the Dutch Meteorological Service (KNMI), used three different methods to assess the role of the human climate influence on record Arctic warmth over November and December.
We used forecast temperatures and heat persistence models to predict what will happen for the rest of December. But even with 10 days still to go, it is clear that November-December 2016 will certainly be record-breakingly warm for the Arctic.
Next, I investigated whether human-caused climate change has altered the likelihood of extremely warm Arctic temperatures, using state-of-the-art climate models. By comparing climate model simulations that include human influences, such as increased greenhouse gas concentrations, with ones without these human effects, we can estimate the role of climate change in this event.
This technique is similar to that used in previous analyses of Australian record heat and the sea temperatures associated with the Great Barrier Reef coral bleaching event.
The November-December temperatures of 2016 are record-breaking but will be commonplace in a few decades’ time. Andrew King, Author provided
To put it simply, the record November-December temperatures in the Arctic do not happen in the simulations that leave out human-driven climate factors. In fact, even with human effects included, the models suggest that this Arctic hot spell is a 1-in-200-year event. So this is a freak event even by the standards of today’s world, which humans have warmed by roughly 1? on average since pre-industrial times.
But in the future, as we continue to emit greenhouse gases and further warm the planet, events like this won’t be freaks any more. If we do not reduce our greenhouse gas emissions, we estimate that by the late 2040s this event will occur on average once every two years.
Watching the trend
The group at KNMI used observational data (not a straightforward task in an area where very few observations are taken) to examine whether the probability of extreme warmth in the Arctic has changed over the past 100 years. To do this, temperatures slightly further south of the North Pole were incorporated into the analysis (to make up for the lack of data around the North Pole), and these indicated that the current Arctic heat is unprecedented in more than a century.
The observational analysis reached a similar conclusion to the model study: that a century ago this event would be extremely unlikely to occur, and now it is somewhat more likely (the observational analysis puts it at about a 1-in-50-year event).
The Oxford group used the very large ensemble of Weather@Home climate model simulations to compare Arctic heat like 2016 in the world of today with a year like 2016 without human influences. They also found a substantial human influence in this event.
Santa struggles with the heat. Climate change is warming the North Pole and increasing the chance of extreme warm events. Climate Central
All of our analysis points the finger at human-induced climate change for this event. Without it, Arctic warmth like this is extremely unlikely to occur. And while it’s still an extreme event in today’s climate, in the future it won’t be that unusual, unless we drastically curtail our greenhouse gas emissions.
As we have already seen, the consequences of more frequent extreme warmth in the future could be devastating for the animals and other species that call the Arctic home.
Geert Jan van Oldenborgh, Marc Macias-Fauria, Peter Uhe, Sjoukje Philip, Sarah Kew, David Karoly, Friederike Otto, Myles Allen and Heidi Cullen all contributed to the research on which this article is based.
You can find more details on all the analysis techniques here. Each of the methods used has been peer-reviewed, although as with the Great Barrier Reef bleaching study, we will submit a research manuscript for peer review and publication in 2017.
Andrew King, Climate Extremes Research Fellow, University of Melbourne
This article was originally published on The Conversation. Read the original article.
The 80,000-odd tourists heading for the North Pole this summer are likely to witness a changing topography: icebergs crumbling into the sea, ice shelves floating away and freely navigable sea lanes that remained icebound just five years ago. Rising global temperature is melting Arctic sea ice, making a piece of the planet accessible for the first time in living memory. On their way the tourists would often encounter cargo liners on exploration missions—each clearing the way for future routes to exploit the frozen pole. These cargo liners herald the intense competition to grab the abundance of natural resources that lie under the melting sea ice. Whether the tourist is from far away India, China or Singapore, he or she will be able to gauge the future economic and political impacts of the disappearing ice caps on his or her respective economy.
Recent scientific studies confirm that the Arctic is warming twice as fast as the rest of the globe. The period between 2005 and 2010 was the warmest since record keeping began in 1840. In September 2011, at the height of its summertime shrinkage, ice caps covered 4.33 million square kilometres of the Arctic Ocean. This, according to the US National Snow and Ice Data Center (NSIDC), was a 50 per cent drop from the average sea ice cover between 1979 and 2000.
The Arctic is also getting thinner and younger. Its thicker, older ice caps that have formed over several years and were able to survive through the summer melt season are increasingly being replaced with ice that accrues over the winter every year and then melts away. This makes the Arctic more vulnerable to global warming. By the reckoning of NSIDC, only five per cent of the Arctic ice caps were over five years old last summer. In the early 1980s as much as 40 per cent of the Arctic sea ice was over five years old. The Intergovernmental Panel on Climate Change (IPCC) in 2007 estimated that the Arctic will have an ice-free summer by the end of this century. A few recent studies predict that this may happen as early as 2030-2040. But no one can say for sure. What everyone is sure about is summer now comes early and stays longer.
“This is a very fast, profound and dramatic change in the earth system. It has significant consequences for the world,” says Vladimir Ryabinin of World Climate Research Programme.
The Arctic’s vast reservoirs of fossil fuel, fish and minerals, including rare earth materials, are now accessible for a longer period. But unlike Antarctica, which is protected from exploitation by the Antarctic Treaty framed during the Cold War and is not subject to territorial claims by any country (see ‘Poles apart’), there is no legal regime protecting the Arctic from industrialisation, especially at a time when the world craves for more and more resources. The distinct possibility of ice-free summer has prompted countries with Arctic coastline to scramble for great chunks of the melting ocean. The scrambling pales the Gold Rush of the 19th century in its scope and degree.
Of the eight Arctic nations—Russia, Sweden, Norway, Iceland, Denmark (Greenland), Finland, Canada and the US—several have explored the Arctic waters and found over 400 oilfields with proven reserves of around 240 billion barrels of crude oil and natural gas. This is about 10 per cent of the world’s known hydrocarbon reserves. They have also discovered significant deposits of various minerals on the seabed.
New reserves will be available with further melting of the polar sea ice. The US Geological Survey estimates that the Arctic holds up to 20 per cent of the world’s unexplored hydrocarbon reserves, with potential oil reserves of 90 billion barrels, natural gas reserves of 47.3 trillion cubic metres and gas condensate reserves of 44 billion barrels. Around 80 per cent of these new discoveries are likely to be found offshore at an easy depth of 500 metres.
As a bonus, the vanishing ice also opens up two new faster shipping routes that sharply reduce the distance between Western countries and Asia by connecting the Pacific and Atlantic oceans. These are the Northwest Passage along the northern coast of North America and the Northeast Passage along the Siberia coast (see map). The Northwest Passage will reduce the distance from US’ Seattle port to Rotterdam in the Netherlands by almost 25 per cent compared to the current route via the Panama Canal. The voyage from Rotterdam to Yokohama in Japan via the Northeast Passage will be 40 per cent shorter than the traditional Suez Canal route. Explorers had long sought these trans-Arctic passages as possible trade routes.
With fast-rising global temperatures, if, as some scientists predict, these passages become navigable round the year in the coming decades, they could redraw the global trading routes. Shipping routes will shift from politically unstable regions like Western Asia and piracy-infested routes like the South China Sea, the Malacca Straits and the Gulf of Aden.
The melting has been so fast that each shipping season attains a new milestone. In August 2008, a Danish cable ship became the first commercial vessel to pass through the Northwest Passage. It saved 15 days on its voyage from Japan to Newfoundland off the east coast of Canada. In September 2010, the first cargo ship with 41,000 tonnes of iron ore sailed through the Northeast Passage to Asia. Around the same time last summer, a Russian ship became the first supertanker to ferry 120,000 tonnes of gas condensate through the route. The largest-ever bulk carrier crossed the ocean when a Japanese ship with 66,000 tonnes of iron ore completed its voyage from Russia’s Kola Peninsula to Jingtang in China. Norway plans to ferry liquified natural gas (LNG) to Japan through the route this summer.
According to Canadian and US maritime experts, nearly two per cent of the ships worldwide could be sailing through the Arctic by 2030, which will grow to five per cent by 2050. Several Arctic countries are planning deep sea ports in the pole. Shipping companies have already built 500 ice-class ships, suitable for the Arctic region. More are under construction.