Tag Archives: Arctic

Bluefin tuna follow prey to warming high Arctic

Large bluefin tuna that were caught among mackerel near Greenland Image: Greenland Fisheries License Control Authority
Large bluefin tuna that were caught among mackerel near Greenland
Image: Greenland Fisheries License Control Authority

By Alex Kirby

A research ship’s surprise catch of bluefin tuna further north than ever recorded indicates that climate change is restructuring the food web as the waters of east Greenland get warmer.

LONDON, 8 September, 2014 − Biologists and fishermen aboard a scientific cruise in the Arctic while they investigated mackerel stocks caught more than they bargained for − three large bluefin tuna, each weighing about 100 kilograms.

The research ship was sailing through the Denmark Strait, which separates Greenland from Iceland. Bluefin tuna are very seldom found near Greenland, and there are no other scientific reports of them venturing that far north. The most recent report of a tuna anywhere near was a stranding in 1900, a long way south at Qaqortoq, on the south-western tip of Greenland.

Details of the find, during a cruise in August 2012 organised by the Center for Macroecology, Evolution and Climate at the University of Copenhagen, have now been published in the journal Global Change Biology.

Expanded range

The lead author, Professor Brian MacKenzie, said bluefin tuna usually search for prey in areas where surface temperatures are warmer than 11°C.

At the time of the catch, the Denmark Strait was unusually warm, and one of tuna’s preferred prey species, mackerel, had already expanded their range into the region.

Professor MacKenzie and his colleagues write: “Regional temperatures in August 2012 were historically high and contributed to a warming trend since 1985, when temperatures began to rise.

“The presence of bluefin tuna in this region is likely due to a combination of warm temperatures . . . and immigration of an important prey species to the region. We conclude that a cascade of climate change impacts is restructuring the food web in east Greenland waters.”

They say their data was too limited to estimate how many tuna came so far north, but because bluefins are a schooling species − with schools having from 10 to 100 individuals − and because the three tuna were caught in the same haul, it is likely there were many more present.

The report says: “Satellite imagery showing the spread of warm water from the south-east towards east Greenland suggests that recent warming and climate change may have opened a migration pathway from the European shelf towards Greenland for migratory species.”

It acknowledges that the fish may have swum to the Denmark Strait from the north-west Atlantic, and concludes: “Our results show that rising temperatures have been progressively leading a . . . trophic [high in the food chain] cascade into east Greenland waters via improved thermal conditions for migratory prey and predator species.”

New fishing quotas

Nobody knows why bluefin tuna disappeared from the waters near Denmark and in the Norwegian Sea during the 1960s, nor when they might return. But Iceland and Norway have been allocated new fishing quotas of 30 tonnes each for the species in 2014.

An adult bluefin tuna is typically 1.5m-2m long, but some have been as big as 4.5m and weighed 650 kg. The fish are highly prized for sushi, especially in Japan.

Further climate-related changes in distributions of commercial fish such as mackerel and herring will mean new fishery and ecosystem management plans are going to be needed, says the report’s co-author, Helle Siegstad, head of the Department for Fish and Shellfish at the Greenland Institute of Natural Resources.

The Denmark Strait tuna will be discussed at the annual science conference of the International Council for the Exploration of the Sea (ICES), which starts on 15 September in the Spanish coastal city of A Coruña. – Climate News Network

Sun sheds light on Arctic carbon puzzle

Sun reflects through ice crystals on the Arctic Ocean Image: Mike Dunn/NOAA Climate Program via Wikimedia Commons
The sun reflects from ice crystals on the Arctic Ocean
Image: Mike Dunn/NOAA Climate Program via Wikimedia Commons

By Tim Radford

Scientists discover that, as the Arctic continues to warm, sunlight will be the major cause of CO2 escaping into the atmosphere from vegetation preserved in frozen soil.

LONDON, 4 September, 2014 − One of the puzzles of the permafrost has been solved by scientists in the US. The key to the carbon cycle in the Arctic north is not the microbe population − it’s the sunlight.

Such a discovery is not, strictly speaking, concerned with climate change, but with the more detailed question of how the world works – specifically, how the carbon that was once plant material gets back into the atmosphere.

However, since the Arctic permafrost is home to half of all the organic carbon trapped in the soils of the entire Earth, the finding is ominous.

The Arctic is one of the fastest warming regions on the planet. As it warms, more and more carbon dioxide is likely to escape from the half-decayed tundra vegetation preserved in the frozen soil and will find its way into the atmosphere, to accelerate still further warming.

For the moment, the study is another piece fitted into place in a wider understanding of the carbon cycle.

Organic carbon

Rose Cory, of the University of Michigan, US, reports with colleagues, in the journal Science, that they measured the speeds at which bacteria and sunlight converted dissolved organic carbon in the lakes and rivers of Alaska.

In the standard domestic garden compost heap, the hard work of turning such things as decaying cabbage stalks, potato peelings and grass cuttings back into carbon dioxide and methane is performed by microbes.

But visible and ultraviolet light beams also pack a punch. They too can oxidise organic carbon and turn it back into gas molecules.

In 2013, Dr Cory and colleagues established that levels of dissolved organic carbon in a region that was once permanently frozen were rising, giving microbes and other conversion processes a chance to get to work.

The researchers took samples of flowing and still water from 135 lakes and 73 rivers on Alaska’s North Slope over a three-year period, and then incubated them under differing conditions of light.

More efficient

They found that sunlight was 19 times more efficient than microbes at processing the carbon, and could account for between 70% and 95% of all the carbon released from Alaskan water.

“We’re likely to see more carbon dioxide released from thawing permafrost than people had previously believed,” Dr Cory said. “We are able to say that because we now know that sunlight plays a key role and that carbon released from thawing permafrost is readily converted to carbon dioxide once it is exposed to sunlight.”

Microbes are less efficient in low temperatures. And the sunlight works more efficiently because it can directly degrade the dissolved organic carbon, and can also convert it into a condition that makes it more accessible for the microbes.

“This is because most of the fresh water in the Arctic is shallow, meaning sunlight can reach the bottom of any river – and most lakes – so that no dissolved organic carbon is kept in the dark,” said Byron Crump, a microbial ecologist at Oregon State University, and a co-author of the report. “Also there is little shading of rivers and lakes in the Arctic because there are no trees.” – Climate News Network

Satellite mapping shows ice caps’ faster melt rate

Surface water flows into a 'moulin' shaft in Greenland's ice cap Image: NASA via Wikimedia Commons
Surface water flows down into a ‘moulin’ shaft in the Greenland ice cap
Image: NASA via Wikimedia Commons

By Tim Radford

Scientists have been able to measure more accurately than ever the thickness of the world’s major ice caps  revealing that melting is causing the loss of 500 cubic kms of ice annually.

LONDON, 1 September, 2014 − German researchers have established the height of the Greenland and Antarctic ice caps with greater precision than ever before. And the new maps they have produced show that the ice is melting at an unprecedented rate.

The maps, produced with a satellite-mounted instrument, have elevation accuracies to within a few metres. Since Greenland’s ice cap is more than 2,000 metres thick on average, and the Antarctic bedrock supports 61% of the planet’s fresh water, this means that scientists can make more accurate assessments of annual melting.

Dr Veit Helm and other glaciologists at the Alfred Wegener Institute’s Helmholtz Centre for Polar and Marine Research in Bremerhaven, Germany, report in the journal The Cryosphere that, between them, the two ice sheets are now losing ice at the unprecedented rate of 500 cubic kilometres a year.

Big picture

The measurements used to make the maps were taken by an instrument aboard the European Space Agency’s orbiting satellite CryoSat-2. The satellite gets closer to the poles − to 88° latitude − than any previous mission and traverses almost 16 million sq km of ice, adding an area of ice the size of Spain to the big picture of change and loss in the frozen world.

CryoSat-2’s radar altimeter transmitted 7.5 million measurements of Greenland and 61 million of Antarctica during 2012, enabling glaciologists to work with a set of consistent measurements from a single instrument.

Over a three-year period, the researchers collected 200 million measurements in Antarctica and more than 14 million in Greenland. They were able to study how the ice sheets changed by comparing the data with measurements made by NASA’s ICESat mission.

More complex

Greenland’s volume of ice is being reduced at the rate of 375 cubic km a year. In Antarctica, the picture is more complex as the West Antarctic ice sheet is losing ice rapidly, but is growing in volume in East Antarctica.

Overall, the southern continent − 98% of which is covered with ice and snow − is losing 125 cubic km a year. These are the highest rates observed since researchers started making satellite observations 20 years ago.

“Since 2009, the volume loss in Greenland has increased by a factor of about two, and the West Antarctic ice sheet by a factor of three,” said Angelika Humbert, one of the report’s authors. − Climate News Network

Pre-history proof of climate’s see-saw sensitivity

The woolly rhinoceros once roamed wild on the plains of Europe Image: Public Library of Science via Wikimedia Commons
The woolly rhinoceros once roamed wild on the plains of Europe
Image: Public Library of Science via Wikimedia Commons

By Tim Radford

Computer simulations reaching back deep into the last Ice Age have enabled scientists to put a historic perspective on how even small variations in the climate system can lead to dramatic temperature change.

LONDON, 24 August, 2014 − It doesn’t take much to change a planet’s climate – just a little shift in the Northern hemisphere glacial ice sheet and a bit more carbon dioxide in the atmosphere. After that, the response is rapid. The tropical rain belt moves north and the southern hemisphere cools a bit, in some sort of bipolar see-saw response.

Sound familiar? It does, and it doesn’t. It all happened long before the internal combustion engine, or even the new Stone Age.

Researchers from the Alfred Wegener Institute’s Helmholtz Centre for Polar and Marine Research, Bremerhaven, the University of Bremen, Germany, and the University of Cardiff in the UK, report in Nature journal that they have made climate simulations that agree with observations of historical climate change that date back 800,000 years.

Long before the present alarms about global warming through the emission of carbon dioxide from fossil fuels, climate researchers were puzzled by the phenomenon of the Ice Ages and the “interglacials” that punctuated those long periods when the Arctic ice extended from the North Pole to the Atlantic coast of France, and over huge tracts of North America.

Vanished species

Mysteriously, and at great speed, the temperatures would rise by up to 10°C and the vast walls of ice would retreat. Lion, hyena and rhinoceros would invade the wild plains of what is now southern England, and now-vanished species of humans would hunt big game and gather fruit and seeds in the valleys and forests of Europe and America.

Since the end 10,000 years ago of the last ice age – itself a very rapid event – was the springboard for agriculture and civilisation, and eventually an Industrial Revolution based on fossil fuels, the story of climate change plays a powerful role in human history.

So any analysis of the tiny shifts in ice cover that seemed to trigger these dramatic, bygone events can be helpful in understanding the long story of the making of the modern world.

The researchers found a tentative scenario involving weak ocean currents, and prevailing winds that shifted the sea ice and allowed the oceans and atmosphere to exchange heat, pushing warmer water into the north-east Atlantic.

These changes precipitated a dramatic warming of the northern hemisphere in just a few decades, and the retreat of the glaciers for an extended period before the ice returned to claim much of the landmass again. But, overall, such changes tended to occur when sea levels reached a certain height.

“The rapid climate changes known in the scientific world as Dansgaard-Oeschger events were limited to a period of time from 110,000 to 23,000 years before the present,” said Xu Zhang, the report’s lead author.

“The abrupt climate changes did not take place at the extreme low sea levels, corresponding to the time of maximum glaciations 20,000 years ago, or at high sea levels such as those prevailing today. They occurred during periods of intermediate ice volume and intermediate sea levels”

Climate swings

Co-author Gerrit Lohmann, who leads the Wegener Institute’s palaeoclimate dynamics group, said: “Using the simulations performed with our climate model, we were able to demonstrate that the climate system can respond to small changes with abrupt climate swings.

“At medium sea levels, powerful forces − such as the dramatic acceleration of polar ice cap melting − are not necessary to result in abrupt climate shifts and associated drastic temperature changes.”

How much this tells anybody about modern climate change is open to debate. Right now, according to this line of evidence, the planet’s climate could be in one of its more stable phases of the Earth’s history.

But while the conditions for the kind of rapid change recorded in pre-history do not exist today, Prof Lohmann warns that “sudden climate changes cannot be excluded in the future”. – Climate News Network

Arctic warming blamed for dangerous heat waves

Feeling the heat: a wildfire rages in New Mexico during the 2012 heat wave in the US Image: Kari Greer/USFS Gila National Forest via Wikimedia Commons
Feeling the heat: a wildfire rages in New Mexico during the 2012 heat wave
Image: Kari Greer/USFS Gila National Forest via Wikimedia Commons

By Paul Brown

Giant waves in the jet stream that often governs our weather are changing as the Arctic warms more rapidly − leading to long periods of soaring temperatures that pose major threats to economies and human health.

LONDON, 16 August, 2014 − Few people have heard of Rossby waves and even less understand them, but if you are sweltering in an uncomfortably long heat wave, then they could be to blame.

New discoveries about what is going on in the atmosphere are helping to explain why heat waves are lasting longer and causing serious damage to humans and the natural world. These events have doubled in frequency this century, and the cause is believed to be the warming of the Arctic.

The weather at the Earth’s surface is often governed by high winds in the atmosphere, known as jet streams. In 1939, Carl-Gustaf Arvid Rossby, a Swedish-born America meteorologist, discovered waves in the northern jet stream that were associated with the high and low pressure systems at ground level that form daily weather patterns.

Jet streams travel at up to 200 kilometres an hour, frequently wandering north and south − with cold Arctic air to the north, and warmer air to the south.

Rapid variations

When the jet stream develops Rossby waves and they swing north, they suck warm air from the tropics to Europe, Russia or the US. And when they swing south, they do the same thing with cold air from the Arctic. The waves constantly change shape, and so cause rapid variations in the weather.

But new research, published in the Proceedings of the National Academy of Sciences of the USA, has discovered a tendency for these waves in the jet stream to get much bigger and to get stuck – particularly in July and August. This causes heat waves that last not just for a few days but for weeks.

This is a serious health and economic threat. A recent example is the record heat wave in the US that hit corn farmers and worsened wildfires in 2012.

Close study of records shows that, from 1980 to 2003, there were two such heat wave events every four years on average. From 2004-07, there were three events, and between 2008-11 there were five.

Ice shrinking

Theory and the new data both suggest a link to processes in the Arctic. Since 2000, the Arctic has been warming about twice as fast as the rest of the globe. One reason for this is that ice is rapidly shrinking in the White Sea − a southern inlet of the Barents Sea on the north-west coast of Russia – and so less sunlight gets reflected back into space, while the open ocean is dark and hence warms more.

“This melting of ice and snow is actually due to our lifestyle of churning out unprecedented amounts of greenhouse gases from fossil fuels,” says Hans Joachim Schellnhuber, co-author of the study and founding director of the Potsdam Institute for Climate Impact Research.

As the Arctic warms more rapidly, the temperature difference to other regions decreases. Yet temperature differences are a major driver of the atmospheric circulation patterns that in turn rule our weather.

“The planetary waves topic illustrates how delicately interlinked components in the Earth system are,” Schellnhuber concludes: “And it shows how disproportionately the system might react to our perturbations.” – Climate News Network

Norway fails to tap new Arctic oil and gas

Melkøya gas plant, 110km south of Statoil’s latest Arctic drilling site Image: Joakim Aleksander Mathisen via Wikimedia Commons
Melkøya gas plant, 110km south of Statoil’s latest Arctic drilling site
Image: Joakim Aleksander Mathisen via Wikimedia Commons

By Alex Kirby

The Norwegian company conducting some of the most northerly drilling operations in the world admits that it has failed so far to find commercially exploitable hydrocarbon reserves in the high Arctic.

LONDON, 12 August, 2014 − Statoil, the Norwegian state-owned company, has announced that it has failed to find commercial quantities of oil and gas in the Barents Sea this year.

The Arctic remains one of the oil industry’s most promising exploration areas. The US Geological Survey says a large part of the world’s remaining hydrocarbon resources − perhaps as much as a quarter of its reserves − is thought to lie in the high northern latitudes of Russia, Norway, Greenland, the US and Canada.

Statoil hoped to find oil in the three test wells it drilled this summer in the high northern Arctic, having made finds in the area in 2011 and 2012.

Dry reservoir

But it has admitted to being disappointed at its latest results, which included a small quantity of natural gas at one site and a dry reservoir at another.

Statoil announced in February this year that drilling in the Johan Castberg oilfield − also in the Barents Sea, off northern Norway and Russia − had produced no oil and little gas.

Irene Rummelhoff, Statoil’s senior vice-president for exploration on the Norway continental shelf, said of the latest drilling operations: “We are naturally disappointed with the results of this summer’s drilling campaign in the Hoop area.”

But the company reaffirmed its confidence in the potential of the area, where the latest drilling was conducted. Rummelhoff said the wells were three out of just six drilled so far in an area measuring 15,000 sq km. Even negative results provided valuable information for further drilling, she said.

“Non-commercial discoveries and dry wells
are part of the game in frontier exploration.”

“We do not have all the answers about the subsurface yet,” Rummelhoff said in a Statoil statement on the exploration programme. “Non-commercial discoveries and dry wells are part of the game in frontier exploration.”

The possibility and the wisdom of trying to recover oil and gas from the unique and very challenging Arctic environment sharply divide environmental campaigners and the energy industry.

In September 2013, Russian security forces detained 30 Greenpeace activists and journalists and seized their vessel, the Arctic Sunrise, during a protest at an offshore oil rig owned by Gazprom, the Russian energy company. The 30, who included four Russians, were held for around two months before being released.

Old partner

The Russian president, Vladimir Putin, had praise for what he called Russia’s “old and reliable partner” Exxon Mobil as he gave the signal on 9 August for the US energy company and its Russian partner, OAO Rosneft, to start drilling a $700 million Arctic Ocean oil well, Russia’s northernmost well.

“Despite current political difficulties, pragmatism and common sense prevails,” he said at the Black Sea resort of Sochi, as he ordered drilling to start.

“Nowadays, commercial success is defined by an efficient international co-operation. Businesses, including the largest domestic and foreign companies, understand this perfectly.”

The facts of climate science support the campaign groups: most of the hydrocarbons that lie beneath the Arctic cannot be burned if the world is to avoid dangerous climate change.

By 2011, the world had used over a third of its 50-year carbon budget. Only 20% of its total reserves can be burned unabated, leaving up to 80% of oil and gas assets technically unburnable. − Climate News Network

Lakes raise new question on Arctic warming

Thermokarst lakes formed in melting permafrost in Alaska. Image: 16Terezka via Wikimedia Commons
Thermokarst lakes formed in melting permafrost in Alaska.
Image: 16Terezka via Wikimedia Commons

By Alex Kirby

Research into the lakes that form when permafrost melts challenges the widely-held view that they are contributing to Arctic temperature rise by releasing carbon into the atmosphere.

LONDON, 4 August, 2014 − Scientists say there is uncertainty over a previously unquestioned assumption about the way in which temperatures are rising in the Arctic.

New research, supported by the US National Science Foundation (NSF), suggests that a rethink is required on the widely-held scientific view that thawing permafrost uniformly accelerates atmospheric warming.

Instead, the scientists say, their findings show that one type of Arctic lake stores more greenhouse gases (GHGs) than it emits into the atmosphere.

But they say the effect is unlikely to be permanent, because increasing Arctic warmth will probably lead to the renewed release of the gases stored in the lakes.

Melted fresh water

The study, published in the journal Nature, focuses on thermokarst lakes, which appear as permafrost thaws and create surface depressions that fill with melted fresh water, converting previously frozen land into lakes.

The research suggests that Arctic thermokarst lakes are “net climate coolers” when observed over millennial timescales.

The Arctic is one of the fastest-warming regions on Earth. Sea ice has been retreating in the last 30 years or so by 12% a decade, NASA says, and spring and autumn on the Greenland icecap have warmed by more than 3°C.

But the new research suggests the lakes have not been contributing to this recent warmth, although thousands of years ago they did release GHGs.

“Until now, we’ve only thought of thermokarst lakes as positive contributors to climate warming,” said lead researcher Katey Walter Anthony, who is associate research professor at the University of Alaska Fairbanks Institute of Northern Engineering.

“It is true that they do warm climate by strong methane emissions when they first form, but on a longer-term scale they switch to become climate coolers because they ultimately soak up more carbon from the atmosphere than they ever release.”

The team found, thermokarst lakes in ice-rich regions of North Siberia and Alaska began cooling about 5,000 years ago. They stopped emitting methane and carbon dioxide, and instead started storing CO2 from peat-rich sediments.

The researchers used published data, their own field observations of Siberian permafrost and thermokarsts, radiocarbon dating, atmospheric modelling and spatial analyses to study how thawing permafrost is affecting climate change and GHG emissions.

Over the millennia, they say, several factors stimulated high rates of carbon deposits in lake sediments. These included thermokarst erosion and accumulations of organic matter, nutrient release from thawing permafrost, and slow decomposition in cold lake bottoms that lacked oxygen.

Carbon uptake

The study’s co-author, Miriam Jones, of the US Geological Survey, said: “These lakes are being fertilized by thawing yedoma permafrost [a type of permafrost rich in organic material]. So mosses and other plants flourish in these lakes, leading to carbon uptake rates that are among the highest in the world, even compared to carbon-rich peatlands.”

The study also found that when the lakes drain, previously thawed organic-rich lake sediments freeze again, storing a large amount of carbon processed in and under thermokarst lakes.

But the researchers say the new carbon storage will not last indefinitely. Future warming will probably start re-thawing some of the permafrost and release some of the carbon it contains.

Roughly 30% of global permafrost carbon is concentrated within 7% of the permafrost region in Alaska, Canada and Siberia. The study has expanded estimates of how much carbon the circumpolar peat stores in permafrost regions by more than 50%.

And it leaves scientists puzzling over a further question. The thermokarst lakes, according to this study, have been storing GHGs, not emitting them. So what else, despite that, is continuing to warm the Arctic faster than most of the rest of the planet? − Climate News Network

Data adds to confusion over polar sea ice

The expansion of Antarctic sea ice may have been overestimated. Image: Jason Auch via Wikimedia Commons
The expansion of Antarctic sea ice may have been overestimated.
Image: Jason Auch via Wikimedia Commons

By Tim Radford

Possible errors in the interpretation of satellite data may help to explain scientists’ puzzlement over indications that sea ice cover is apparently increasing in the Antarctic, but is shrinking visibly in the Arctic.

LONDON, 26 July, 2014 − Scientists believe they may have found explanations for two inconsistencies in their understanding of global warming.

One cause for head scratching is in the Antarctic, where the sea ice seems to be getting bigger when it ought to be shrinking, and another has been the apparent slowdown overall in the rate of global warming for the last decade.

Climate scientists around the world have been picking away at both puzzles, and not just because climate sceptics and energy industry lobbyists use them as ammunition to argue that global warming is not a problem at all. Scientists are naturally unhappy when data doesn’t match their predictions − and they want to know the reason why.

The Antarctic problem is hard to miss. The Arctic Ocean sea ice is shrinking visibly, and the entire sea could be ice-free most summers in a few decades. But even though there is clear evidence from separate sources that West Antarctica is responding to climate change, the southern hemisphere ice cover, overall, has been increasing.

Or has it? Ian Eisenman, a climatologist at the Scripps Institution of Oceanography at the University of California San Diego, begs to differ. He and colleagues report, in The Cryosphere journal, that it could be due to an error in the way satellite data is processed.

Spliced together

Scientists have been using satellite data to check sea ice cover for 35 years. But the data does not come from one instrument on just one satellite: observations transmitted from a series of satellites have been spliced together.

One report from the Intergovernmental Panel on Climate Change said the sea ice cover was more or less constant, but a later report said it had grown by 16,500 square kilometers a year between 1979 and 2012.

“When we looked at how the numbers reported for the trend had changed, and we looked at the time series of Antarctic sea ice, it didn’t look right,” Dr Eisenman said.

The researchers think that the difference between the two datasets might be linked to a change in satellite sensors in 1991, and the way the data collected by the two instruments was calibrated. What the Scripps team has done is identify a source of possible error, but it hasn’t settled the question one way or the other.

Since the Arctic and Antarctic are very different places, it would be unrealistic to expect the patterns of melting to be the same. And it may still be that southern hemisphere sea ice is growing.

However, while that question remains open, there is less doubt about the long slowdown in the rate of average global warming during the 21st century.

Missing heat

Separate teams of researchers have proposed a series of possible explanations for the failure of the climate to keep up with the projections of the climate scientists. These have included the suggestion that the missing heat may be “concealed” in the deep oceans, and that a pause in warming was going to happen anyway, but it just happened earlier than anyone expected.

Shaun Lovejoy, professor of physics at McGill University in Canada, reports in Geophysical Research Letters that there is yet another explanation. He argues, from statistical analysis, that coincidentally with the increase in man-made emissions of greenhouse gases, there has been a natural cycle at work, and that the most recent human impact on climate has been damped down by a cooling phase.

He had already ruled out with 99% certainty the possibility that natural variation could explain all the ups and downs of global average temperatures since 1800. This time he used the same statistical approach to the data for the 15 years from 1998 to the present.

His research suggests that there has been a natural cooling of 0.28°C to 0.37°C since 1998, which is in line with natural variations that occur every 20 to 50 years. “The pause has a convincing statistical explanation,” Lovejoy says. – Climate News Network

Svalbard’s reindeer thrive as climate warms

Warm welcome: Svalbard's distinctive reindeer are increasing in numbers. Image: courtesy of Dr Jonathan Codd, University of Manchester
Warm welcome: Svalbard’s distinctive reindeer are increasing in numbers
Image: courtesy of Dr Jonathan Codd, University of Manchester

By Alex Kirby

The rising temperatures that have many negative impacts in the Arctic region are not a problem for a Norwegian subspecies of reindeer whose population increased by a remarkable 30% last year.

LONDON, 21 July, 2014 − There will be winners as well as losers as climate change intensifies, and scientists say they have just found one species that is prospering already.

Far from threatening the reindeer on the Norwegian high Arctic archipelago of Svalbard, rising temperatures appear to be driving a remarkable increase in the animals’ numbers.

Scientists from the University of Manchester, UK, and the Arctic University of Norway in Tromsø have found that the numbers of Svalbard reindeer, continuing a trend that has been observed over the last 36 years, increased by 30% in the last year.

Physically counted

The scientists established the population spurt by counting the reindeer in the valley of Adventdalen, in central Spitsbergen. They say their research is one of only very few studies on animal populations and climate change that involves animals being physically counted annually, rather than estimated.

The total number of animals − including all births and all deaths − in Adventdalen has been recorded annually since 1979 by a team led by Dr Nicholas Tyler, of the Arctic University of Norway.

Svalbard’s reindeer population had increased in close parallel with winter warming in the last 35 years, growing from an average of around 600 animals in the early 1980s to around 1,000 today.

Dr Tyler said: “Winter warming is widely held to be a major threat to reindeer across the Arctic, but, in Svalbard, global warming has had the opposite effect. Our data provides remarkable confirmation of this counter-intuitive observation.”

This summer, a team from Manchester, led by Jonathan Codd and Nathan Thavarajah, helped with the annual census of reindeer in Adventdalen.

Dr Codd, the programme director for zoology at the university, said: “The results revealed a remarkably successful year for Svalbard reindeer. Despite very high numbers in 2013, the population increased by almost 30% and reached a new record of just over 1,300 animals − more than three times the population size in 1979, when the present series of counts began.”

The team found very little winter mortality and very high calving. There were over 300 calves in the valley, the second highest number recorded.

Streets awash

“The substantial increase in the numbers of reindeer is linked with frequent and pronounced periods of warm weather last winter,” said Dr Codd. “In February, the temperature rose above freezing for six days, reaching a maximum of +4.2°C, and the streets of the Norwegian settlement at Longyearbyen were reported awash with melt water.”

Dr Codd told the Climate News Network: “We count the reindeer by walking the same set routes every day, and there is no possibility of any double counting.

“There are signs that Svalbard’s predators are in good shape. I think most of the polar bear populations are at least stable, and the Arctic foxes are doing pretty well too.

“But neither seems to be bothering the reindeer. The foxes will eat dead deer, but don’t attack live ones. And the main prey of the bears is seals.

“And the reindeer can move fast if they need to. I’ve heard reports that they have been known to reach a speed of 50 miles an hour (80 kph).” − Climate News Network

Hi-tech quest for Arctic sea ice answers

Walrus surfacing through sea ice off the Alaska coast Image: Joel Garlich Miller/USFWS via Wikimedia Commons
Breakthrough: walrus surfacing in sea ice off the coast of Alaska
Image: Joel Garlich Miller/USFWS via Wikimedia Commons

By Tim Radford

A sophisticated array of automatic sensors will allow scientists to conduct the longest ever monitoring programme to determine the precise physics of summer sea ice melt in the Arctic.

LONDON, 20 July, 2014 − An international team of scientists plan to spend months watching ice melt. But although it will take longer and cost a lot more than watching paint dry, it will be much more interesting and rewarding.

They plan to discover just how the Arctic ice retreats, the rate at which it melts, and the oceanographic processes at work.

The Arctic ice cap is a vital part of the climate machine, and the basis of an important ecosystem. But although the polar ice once stretched far further south, it has been both thinning and shrinking for more than three decades. This melting shows signs of accelerating, with consequences for nations far to the south, but researchers still don’t know much about the physics of the process.

Suite of technologies

So the US Naval Research Laboratory, oceanographers from France and the US, the British Antarctic Survey, the Korean Polar Research Institute, the Scottish Association for Marine Science, and the Universities of Cambridge in the UK and Yale in the US have co-ordinated a suite of technologies to monitor every detail of this summer’s ice retreat from the Alaskan shoreline, northwards.

They will use an array of floats, buoys, sensors, thermometers, tethers, GPS receivers and automated weather stations to measure every detail, such as the flow of warmer water, growth and pattern of waves, the wind speed and direction, air pressure, and humidity.

There will be buoys fixed in the ice to record both the melting and – later in the year – its refreezing, and an array of ice-tethered profilers to monitor the changes in the upper ocean. Autonomous sea gliders, too, will be released to explore below the ice shelf and report back every time they surface.

The Arctic summer ice is an example of positive feedback. Ice reflects sunlight, so it is its own insulator, and keeps itself cold. But as it melts and retreats, the exposed darker ocean waters can absorb more radiation, and bring more warmth to the edges of the retreating ice, thus accelerating the process.

It freezes again, but – on average – each year the ice cap becomes thinner, and the total area frozen continues to shrink. Researchers think they understand the big picture, but now they want the confirmatory fine detail.

Melt season

“This has never been done at this level, over such a large area and for such a long period of time,” said Craig Lee, of the University of Washington, who leads the Marginal Ice Zone Programme project. “We’re really trying to resolve the physics over the course of an entire melt season.”

The project began in March, when researchers planted an array of sensors along a line 200 miles to the north of Alaska. In August, a Korean icebreaker will install more equipment, and a team from Miami is studying high resolution satellite pictures of ice floes in the region. Biologists will also want to understand the effect of temperature changes on marine micro-organisms.

“The field programme will provide unique insight into the processes driving the summer melt of Arctic ice,” Dr Lee said. “It’s the automation and unprecedented collaboration that allows us to be out there for the entire season. You couldn’t afford to be out there at this intensity, for this length of time, any other way.” − Climate News Network