Tag Archives: Ice melt

Climate data shows clear signs of warming

Wreckage caused by Super Typhoon Haiyan in the Philippines last year Image: Eoghan Rice, Trócaire/Caritas via Wikimedia Commons
Wreckage caused by Super Typhoon Haiyan in the Philippines last year
Image: Eoghan Rice, Trócaire/Caritas via Wikimedia Commons

By Alex Kirby

Hundreds of scientists from 57 countries have fed evidence into a new report that provides a clear picture of how patterns, changes, and trends of the global climate system show that our planet is becoming a warmer place.

LONDON, 24 July, 2014 − However you view the evidence, whatever set of measurements you examine, the picture that emerges is consistent: the Earth is heating up.

The US National Oceanic and Atmospheric Administration (NOAA) reports: “In 2013, the vast majority of worldwide climate indicators − greenhouse gases, sea levels, global temperatures, etc − continued to reflect trends of a warmer planet.”

This, NOAA says, is the picture painted by the indicators assessed in a report, State of the Climate in 2013, published online by the American Meteorological Society.

Scientists from NOAA’s National Climatic Data Center were the lead editors of the report, compiled by 425 scientists from 57 countries. It provides a detailed update on data collected by monitoring stations and instruments on air, land, sea and ice.

“These findings reinforce what scientists for decades have observed: that our planet is becoming a warmer place,” said the NOAA‘s administrator, Dr Kathryn Sullivan.

Changes tracked

The report tracks patterns, changes, and trends of the global climate system, including: greenhouse gases; temperatures throughout the atmosphere, ocean, and land; cloud cover; sea level; ocean salinity; sea ice extent; and snow cover.

It says greenhouse gases continued to climb, with concentrations of major gases − including carbon dioxide (CO2), methane and nitrous oxide − once again reaching historically high levels. Atmospheric CO2 concentrations rose by 2.8 parts per million (ppm) in 2013 and reached a global average of 395.3 ppm for the year.

Many scientists argue that once CO2 concentrations reach 450 ppm it will be difficult to prevent global average temperatures from rising more than 2°C above their level for most of human history. The present rate of increase suggests that, without drastic emission cuts, that threshold will be reached before mid-century.

Four major independent datasets show that 2013 was among the warmest years on record, ranking between second and sixth, depending upon the dataset used. Sea surface temperatures increased to place 2013 among the 10 warmest on record.

Sea level also continued to rise, in step with a trend of 3.2 ± 0.4 mm per year over the past two decades.

The Arctic went on warming , marking its seventh warmest year since records began in the early 20th century. Record high temperatures were measured at a depth of 20 metres at permafrost stations in Alaska.

The Arctic sea ice extent was the sixth lowest since satellite observations began in 1979. All seven lowest sea ice extents on record have occurred in the past seven years.

Contradictory trends

The Antarctic, too, was consistent, even if only in the apparently contradictory trends it showed. The extent of the sea ice reached a record high for the second year in a row, of 7.56 million square miles on October 1 −  0.7% higher than the previous record high of 7.51 million sq miles in 2012 and 8.6% higher than the record low maximum of 6.96 million sq miles in 1986. But the South Pole station experienced its highest temperature since records began in 1957.

The number of tropical cyclones during 2013 was slightly above average, but the North Atlantic Basin had its quietest season since 1994. However, in the Western North Pacific Basin, Super Typhoon Haiyan had the highest wind speed ever known for a tropical cyclone, with one-minute sustained winds estimated at 196 miles per hour. − Climate News Network

  • State of the Climate in 2013 is the 24th edition in a peer-reviewed series published annually as a special supplement to the Bulletin of the American Meteorological Society.

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

Emissions are fuelling Australian droughts

Water depth marker in Lake Albert, South Australia Image: Bidgee via Wikimedia Commons
Water depth marker in the dried out bed of Lake Albert, South Australia
Image: Bidgee via Wikimedia Commons

By Tim Radford

The Australian prime minister may be scathing about climate science, but new research shows that burning fossil fuels is a significant factor in the long-term rainfall decline that is leaving southern regions of the country parched and sweltering.

LONDON, 17 July, 2014 − American scientists have just confirmed that parts of Australia are being slowly parched because of greenhouse gas emissions – which means that the long-term decline in rainfall over south and south-west Australia is a consequence of fossil fuel burning and depletion of the ozone layer by human activity.

Such a finding is significant for two reasons. One remains contentious: it is one thing to make generalised predictions about the consequences overall of greenhouse gas levels, but it is quite another to pin a measured regional climatic shift directly on human causes, rather than some possible as-yet-unidentified natural cycle of climatic change.

The other is contentiously political. Australia’s prime minister, Tony Abbott, has in the past dismissed climate science as “crap”, and more recently has cut back on Australian research spending.

Australia has already experienced a pattern of heat waves and drought – punctuated by catastrophic flooding – and even now, in the Australian winter, New South Wales is being hit by bush fires.

Tom Delworth, a research scientist at the US National Oceanic and Atmospheric Administration, reports in Nature Geoscience that he and a colleague conducted a series of long-term climate simulations to study changes in rainfall across the globe.

Pattern of change

One striking pattern of change emerged in Australia, where winter and autumn rainfall patterns are increasingly a cause of distress for farmers and growers in two states.

The simulation showed that the decline in rainfall was primarily a response to man-made increases in greenhouse gases, as well as to a thinning of the stratospheric ozone layer in response to emissions of destructive gases by human sources.

The computer simulations tested a series of possible causes for this decline, such as volcanic eruptions and changes in solar radiation. But the only cause that made sense of the observed data was the greenhouse explanation.

South Australia has never been conspicuously lush and wet, but decline in precipitation set in around 1970, and this decline has increased in the last four decades. The simulations predict that the decline will go on, and that average rainfall will drop by 40% over south-west Australia later this century.

Dr Delworth described his model as “a major step forward in our effort to improve the prediction of regional climate change”.

In May, scientists proposed that greenhouse gas emissions were responsible for a change in Southern Ocean wind patterns, which in turn resets the thermostat for the world’s largest island.

Australian scientists report in Geophysical Research Letters that they, too, have been using climate models to examine Antarctic wind patterns and their possible consequence for the rest of the planet.

Temperature rise

“When we included projected Antarctic wind shifts in a detailed global ocean model, we found water up to 4°C warmer than current temperatures rose up to meet the base of the Antarctic ice shelves,” said Paul Spence, a researcher at Australian Research Council’s Centre of Excellence for Climate System Science. This temperature rise is twice previous estimates.

“This relatively warm water provides a huge reservoir of melt potential right near the grounding lines of ice shelves around Antarctica,” Dr Spence said. “It could lead to a massive increase in the rate of ice sheet melt, with direct consequences for global sea level rise.”

Since the West Antarctic ice sheet holds enough water to raise sea levels by 3.3 metres, the consequences would indeed be considerable.

“When we first saw the results it was quite a shock,” Dr Spence said. “It was one of the few cases where I hoped the science was wrong.” – Climate News Network

New clue to Antarctic food-web puzzle

Strength in numbers: thousands of Adélie penguins at a rookery Image: Michael Van Woert/NOAA NESDIS, ORA via Wikimedia Commons
Strength in numbers: thousands of Adélie penguins in an Antarctic rookery
Image: Michael Van Woert/NOAA NESDIS, ORA via Wikimedia Commons

By Tim Radford

A landmark research study that shows one species of penguin is thriving while other populations are in rapid decline offers new insight into how climate change is affecting Antarctica.

LONDON, 16 July, 2014 − Good news from Antarctica: the continent may be warming, the ice shelf may be at risk, and the food chain may ultimately become precarious, but the Adélie penguin population – at least for the moment − is higher than ever before.

The news does not suggest that global warming and climate change are actually good for this important indicator species, which has certainly been in decline on the Antarctic Peninsula. But it does represent an advance: for the first time, a comprehensive study has concluded with a full census of the species.

Heather Lynch, assistant professor of ecology and evelotion at Stony Brook University in New York, and Michelle La Rue, research fellow at the University of Minnesota’s Polar Geopspatial Center, used high resolution satellite imagery to measure levels of penguin guano – the fertiliser industry’s preferred term for seabird excrement – on the continent.

They then used that as the basis for calculating the numbers of birds in a colony necessary to account for all that digested and evacuated seafood.

They report in a journal called The Auk: Ornithological Advances that they identified at least 17 populations of Adélie penguins not previously known to exist, but failed to pinpoint 13 already-recorded colonies, and declared eight of them eradicated.

Their estimate for the total Adélie population in and around the Southern Ocean stands at 3.79 million, which is 53% higher than all previous estimates.

Useful evidence

The researchers call their work a “landmark” study, and see it not as evidence that climate change is going to work for the benefit of one particular species, but more as a useful piece of the great food-web puzzle in a changing climate.

Penguins have been in rapid decline in the West Antarctic Peninsula, which has become one of the fastest-warming regions on the planet. Warmer weather and increased rain have already started to take toll of Magellanic penguins in Argentina, and researchers recently predicted long-term decline for the iconic Emperor penguin on Antarctica itself.

But this is only long-term decline. As long as Antarctica stays cold and the ice shelf stays stable, the researchers say, the population could, in the short term, actually rise.

That is because what matters most to the species that nest in Antarctica is the supply of fish and krill around the continent’s edge. The health and resilience of the Adélie population – and the Emperor penguin, the leopard seal, the cetaceans, and so on – ultimately depend on how the krill and fish populations respond to climate change.

Humans, too, fish for commercial supplies of Antarctic krill, which provides a source of food for fish farms.

“Our finding of a 53% increase in Adélie penguin breeding abundance, compared to 20 years ago, suggests that estimates of krill consumption by this species may be seriously underestimated,” Dr Lynch said. “Leaving enough prey for natural krill predators is an important element in ensuring fisheries proceed sustainably.”

But a second team confirms in Nature Communications that there are strong links between climate and marine life, and that changes in factors such as wind speed and sea ice can have knock-on effects right around the Antarctic food web.

Since 1990, scientists aboard US research vessels have been conducting annual surveys along the western side of the Antarctic Peninsula, measuring populations of photosynthetic algae.

These peak every four to six years, according to changes in atmospheric pressure between the mid-latitudes and Antarctica itself.

Glacial meltwater

In winter, when cold southerly winds blow across the Peninsula, the winter ice extends. Winds drop from spring to summer, reducing the retreat of the ice. So the water column in summer then is stable, and the phytoplankton multiply, fed by iron-rich glacial meltwater.

The blooms of phytoplankton are what the krill need to multiply, and when the krill are around in huge volumes, the Adélie and other penguins, fur seals, baleen whales and albatross don’t have to go so far to find food.

But marine scientist Grace Saba, who did her research while with the Virginia Institute of Marine Science, before moving to Rutgers University, New Jersey, reports that these ideal conditions – negative phases of the Southern Annular Mode (SAM), to give it the technical terminology – are not guaranteed in future. If the world goes on burning fossil fuels, conditions will probably change.

“Projections from global climate models under business-as-usual emission scenarios up to the year 2100 suggest a further increase in temperature and in the occurrence of positive-SAM conditions,” Dr Saba said.

“If even one positive SAM episode lasted longer than the krill lifespan – four to six years with decreased phytoplankton abundance and krill recruitment – it could be catastrophic to the krill population.”  − Climate News Network

Atlases reveal climate and weather impacts

NASA says Arctic sea ice thickness in some areas has halved since 1980 Image: Hannes Grobe 20:05 via Wikimedia Commons

NASA says Arctic sea ice thickness in some areas has halved since 1980
Image: Hannes Grobe 20:05 via Wikimedia Commons

By Alex Kirby

Two new atlases provide clear visual evidence of the effect climate change and extreme weather can have on people and property.

LONDON, 12 July 2014 – For people who find it hard to believe the Earth really is warming, new visual evidence will soon be available – two atlases, one showing graphically the retreat of Arctic ice, the other the human and economic price exacted by extreme weather.

The 10th edition of the National Geographic Atlas of the World is to be published on 30 September. The publication’s geographer, Juan José Valdés, says the reduction in multi-year ice – ice that has survived for two summers – is so noticeable compared with previous editions that it is the biggest visible change since the breakup of the USSR.

“You hear reports all the time in the media about this,” he said. “Until you have a hard-copy map in your hand, the message doesn’t really hit home.” He believes atlases “open people’s eyes to what’s happening in the world.”

The Arctic sea ice has been retreating in the last 30 years or so by 12% each decade, NASA says. (On land the change is even more marked. Spring and autumn on the Greenland icecap have warmed by more than 3°C, although summer temperatures have not changed)

According to NASA’s Operation IceBridge the sea ice is now as much as 50% thinner than in previous decades, falling from an average thickness of 3.8 metres (12.5 feet) in 1980 to 1.9 m (6.2 ft) in recent years. May 2014 represented the third lowest extent of sea ice for that month in the satellite record, the US National Snow and Ice Data Center (NSIDC) says.

Self-supporting

The ice loss is accelerated by what scientists call a positive feedback: the warming in effect fuels itself. Thin ice reflects light less effectively than thick ice, allowing more sunlight to be absorbed by the ocean, which further weakens the ice and warms the ocean even more.

The melting ice also triggers another feedback. Thinner ice is flatter and scientists say this allows melt ponds to accumulate on the surface, reducing the ice’s reflectiveness and absorbing more heat.

In National Geographic’s atlas the multi-year ice, which is older, is shown as a large white mass, with the maximum extent of sea ice – the pack ice that melts and refreezes each season – shown by a simple line. This edition shows the area of multi-year ice is strikingly smaller than previously.

Some scientists say the atlas should show the total ice area at the end of the Arctic summer, including the remaining ice newly formed in the previous winter. This total minimum cover is measured in September, while total maximum cover is measured in March, at the end of winter.

Omitting the minimum cover means ice one year old or less is not being shown, the critics say. But the mapmakers say they do not show the minimum extent because there is only so much information they can include without confusing users.

There is also criticism of the atlas’s reliance on a single year (the new edition uses 2012 data, an extremely low year for ice cover). The critics say this probably over-emphasises long-term trends. But if 2013, a year with more ice, is shown, the mapmakers counter, it could under-emphasise the trend towards rising temperatures.

Steep underestimate

The second publication, the Atlas of Mortality and Economic Losses from Weather, Climate and Water Extremes 1970-2012, is the work of the World Meteorological Organization (WMO) and the Centre for Research on the Epidemiology of Disasters (CRED) of the Catholic University of Louvain (UCL) in Belgium.

Disasters caused by such extremes, it says, are increasing globally, killing people and slowing economic and social development by years or decades. The period covered, the authors say, saw 8,835 disasters, 1.94 million deaths and US$2.4 trillion of economic losses resulting from droughts, extreme temperatures, floods, tropical cyclones and related health epidemics.

Preparations start in Geneva, Switzerland, on 14 July for the third World Conference on Disaster Risk Reduction, to be held in Japan in March 2015 by the United Nations.

Jochen Luther of WMO told the Climate News Network: “It’s not necessarily the number of extreme events that is increasing, but the increasing exposure and vulnerability that turns them into disasters, as well as better reporting of them than in the past.”

The UN’s Global Assessment Report on Disaster Risk Reduction 2013 said direct and indirect losses from natural hazards of all kinds had been underestimated by at least half because of problems with data collection. – Climate News Network

Whalers tale sheds new light on Arctic ice

Oil painting by John Wood (1798-49) of British whalers circa 1840 Image: Lee and Juliet Fulger Fund via Wikimedia Commons
Oil painting by John Wood (1798-1849) of British whalers circa 1840
Image: Lee and Juliet Fulger Fund via Wikimedia Commons

By Tim Radford

Vital data on the Arctic ice sheet before extensive fossil fuel use began to impact on climate has been gleaned from a new study analysing the log books of British whaling ships’ journeys more than 200 years ago.

LONDON, 5 July, 2014 − British whaling ships from Tyneside in the north-east of England made 458 trips to the edge of the Arctic ice between 1750 and 1850. Their log books contained detailed records of perilous journeys, whales caught, and the tons of blubber and barrels of oil they brought home.

For Matthew Ayre, a PhD student at the University of Sunderland, UK, and Dennis Wheeler, the university’s Emeritus Professor of Climatology, these log books and other records by merchant ships and Arctic explorers such as Sir John Franklin − who tried in 1845 to navigate the icy North-West Passage between the Atlantic and the Pacific − represent an extraordinary resource.

They give an account of the southern edge of the ice sheet, the prevailing weather, the spring and summer extremes, the storms, and the condition of the Arctic ice shelf.

Planetary climate

And the log books offer a snapshot of conditions in the century before the first systematic use of fossil fuels began subtly to alter the planetary climate.

The catch, of course, is that the log books were composed in the technical language used by the masters of sailing ships more than 200 years ago, augmented by the jargon appropriate to a trade abandoned by the British more than a century ago.

For Ayre, the first great challenge was to compile a systematic sea ice dictionary and translate it into the language used by scientists today. He then validated his data with five weeks on the US Coastguard ice breaker and research vessel, USCGC Healy, exploring the edge of the polar ice at first hand. His study, which is part of the collaborative ARCdoc project, concentrates on the Davis Straits between north America and Greenland, and the north-west Atlantic.

The evidence confirms satellite observations made in the last three decades that the extent of the polar ice was once far greater, and that the Arctic ice is in historic retreat.

“Significantly, this is the first time we have ever had direct observational information on the ice fronts in the north Atlantic and the Davis Straits area before 1900,” Dr Wheeler said. “Until the introduction of satellite information from the 1970s, we didn’t know what the ice was doing.

“These log books contain absolutely vital
climatological information”

“Well, now we know it was more advanced − therefore, the retreat of the ice in the last 30 years is part of a more recent and new pattern of climate change. So these log books contain absolutely vital climatological information.”

All systematic weather records are relatively recent. The oldest continuous temperature series dates from England in 1659, but records from most of the world, until the last century, were random or simply sparse.

So climate researchers go for what they call proxy data – such as ice cores, lake sediments and tree rings – that provides overall clues to changing patterns of climate during the millennia.

There are other secondary sources – such as monastery and historic estate archives recording farm yields − that offer clues to bygone summers.

Life or death

But the richest resource is probably the log books of the naval ships and merchantmen, the whalers and adventurers who took to the seas in the great age of exploration that began in the 16th century. For such men, the state of the ice and the weather at its edge was a matter of life or death.

The challenge was to match what 18th-century observers recorded with the scientific observations to be made now.

Ayre got his chance aboard the US research vessel, using as a guide an epic account of the Arctic regions, written in 1820 by the Whitby whaler and pioneer scientist, William Scoresby.

“I was making observations every four hours aboard Healy, using Scoresby’s definitions and the Healy researchers’ own daily records, testing how accurate our data is to validate what is in the sea ice dictionary,” Ayre said.

“Apart from modern day research vessels, these are the only books in history from ships that seek out the ice edge in great detail and follow it.” – Climate News Network

Emperor penguin’s Antarctic realm is in peril

 

Iconic pose: emperor penguins' habitat is under serious threat Image: John Landis/NSF via Wikimedia Commons
Iconic pose: emperor penguins’ habitat is seriously threatened by climate change
Image: John Landis/NSF via Wikimedia Commons

By Tim Radford

Loss of Antarctic sea ice through climate change threatens the emperor penguin’s habitat to such an extent that scientists say it should now be made an iconic symbol – like China’s endangered giant panda – of the wildlife conservation movement.

 

LONDON, 3 July, 2014 − Global warming will this century take its toll of Antarctica’s most regal predator, the emperor penguin. There are now 45 colonies of this wonderful bird, but by 2100 the populations of two-thirds of these colonies will have fallen by half or more.

Stéphanie Jenouvrier, a biologist at the Woods Hole Oceanographic Institution in the US, and colleagues from France and the Netherlands report in Nature Climate Change that changes in the extent and thickness of sea ice will create serious problems for a flightless, streamlined ,survival machine that can live and even breed at minus 40°C, trek across 120 kilometres of ice, and dive to depths of more than 500 metres.

The researchers took all the data from 50 years of intensive observation of one colony in Terre Adélie and used climate models to project a future for the other 44 colonies known in the Antarctic.

Decisive factor

They found that the decisive factor in emperor penguin survival was the sea ice. If the seas warmed and there wasn’t enough ice, then that affected the levels of krill in the southern ocean, and therefore reduced the available prey. It also made the penguins more vulnerable to other predators.

If the opposite happened and there was too much sea ice, then foraging trips took longer and penguin chicks were less likely to survive.

Aptenodytes forsteri – the Linnean name for the emperor – is not in trouble yet, and its numbers may even grow in the years up to 2050. But this growth won’t last, and decline is likely everywhere. Climate change has already begun to affect penguin species much further north, in Argentina, by taking toll of young chicks.

Endangered class

For different reasons, the average rise in global temperatures forecast by the Intergovernmental Panel on Climate Change (IPCC) could push the emperor into the endangered class.

“If sea ice declines at the rates projected by the IPCC climate models, and continues to influence emperor penguins as it did in the second half of the 20th century in Terre Adélie, at least two-thirds of the colonies are projected to have declined by greater than 50% from their current size by 2100,” Dr Jenouvrier said.

“None of the colonies, even the southernmost locations in the Ross Sea, will provide a viable refuge by the end of the 21st century.”

The researchers end their paper by arguing that the emperor should – like the giant panda in China – become an icon for the conservation movement.

They conclude: “We propose that the emperor penguin is fully deserving of Endangered status due to climate change, and can act as an iconic example of a new global conservation paradigm for species threatened by future climate change.” – Climate News Network

Icebergs strip away rich Antarctic habitat

Icy waters near the Rothera research station in Antarctica Image: Vincent van Zeijst via Wikimedia Commons
Icy waters near the Rothera research station in West Antarctica
Image: Vincent van Zeijst via Wikimedia Commons

By Tim Radford

The scouring effect of drifting icebergs that are increasingly breaking free from Antarctic ice shelves as a result of global warming is wiping out fauna that cling to the boulders in shallow waters

 LONDON, 23 June, 2014 − A once-rich habitat in the Antarctic has become an impoverished zone as icebergs, increasingly breaking free from the surrounding sea ice because of global warming, scour the shallow-water rocks and boulders on which a diversity of creatures cling to life.

A report in the journal Current Biology says that researchers who carried out a survey dive in 2013 at Lagoon Island, off the West Antarctic Peninsula, discovered that “no live mega or macro-fauna can be found, the first time this has been observed there, despite being regularly visited by scientific divers since 1997”.

David Barnes, of the British Antarctic Survey, and colleagues report that boulders on the seabed near the Rothera research station had once been richly encrusted with creatures that competed for living space. Now such rocks might only support a single species.

Early warning system

“The Antarctic Peninsula can be considered an early warning system, like a canary in a coal mine,” Dr Barnes said. “Physical changes there are among the most extreme and the biology considered quite sensitive, so it was always likely to be a good place to observe impacts of climate change.

“But impacts elsewhere are likely to be not too far behind. A lot of the planet depends on the near shore environment, not least for food. What happens there to make it less stable is important.”

A research diver surveys the shallow waters of West Antarctica Image: British Antarctic Survey
A research diver surveys the shallow waters off the West Antarctic Peninsula
Image: British Antarctic Survey

Climate change has already begun to affect Antarctica in different ways. Researchers last year found that as icebergs broke free, the surviving ice shelf had begun to melt from underneath from underneath. The effect of the drifting bergs was mixed: at depth in the fjords of the Peninsula, for instance, the species variety seemed to have got richer, according to one set of observations.

But no such effect was observed in the ocean shallows that are being scraped and scoured by drifting icebergs. The researchers say that although no species has disappeared entirely from the region, the numbers are so low as to be negligible.

In 2013, most of the observations seemed to involve just one opportunistic or pioneer species, a suspension feeder called Fenstrulina rugula. What had once been a rich habitat had become one of the simplest seabed systems to be found anywhere.

Ecological roles

“Reduction of complex systems into very simple ones, where many (formerly important) species become too rare to maintain meaningful ecological roles, is a common reaction to anthropogenic disturbance such as overfishing, pollution, introductions of non-indigenous species, and habitat destruction,” the report’s authors say.

“Across West Antarctica, the levels of these disturbances are among the lowest globally, apart from greenhouse contributions to climate change.”

The scientists conclude: “We expect the deeper seabed to become richer in benthic colonisation with more ice shelf collapses and fast ice losses, but hard surfaces in the shallows are likely to become deserts dominated by rapidly-colonising pioneers and responsive scavengers.” − Climate News Network

Flow chart unclear for glacial rivers

 

Confluence of the Indus and Zanskar rivers that rise in Tibet SImage Sundeep Bhardway via Wikimedia Commons
Confluence of the glacial Indus and Zanskar rivers flowing from Tibet
Image: Sundeep Bhardwaj via Wikimedia Commons

By Kieran Cooke

Glaciers in the high Himalayas and on the Tibetan Plateau are a vital source of water for millions of people in Asia, but scientists question what will happen to supplies if the rate of melting continues to rise due to climate-related factors

 

LONDON, 19 June – A new study examining river basins in the Asia region suggests that amounts of water supplied to the area by glaciers and rainfall in the Himalayas will increase in the coming decades.

At first reading, that looks like good news, as an estimated 1.3 billion people in Pakistan, India, Bangladesh, Nepal, China and elsewhere are dependent for their water supplies on rivers fed by glaciers and snowmelt.

But the less welcome news is that scientists are unsure what will happen after 2050 if the rate at which glaciers melt continues to increase as a result of climate change.

Scientists say rising temperatures and more intense rainfall patterns in the higher Himalayas are causing the retreat of the majority of glaciers in the region.

Heat build-up

They say glacier melt is also being caused by black carbon – particulate matter that, in South Asia, comes mainly from cooking fires, the burning of waste, plus coal burning and diesel exhausts. The black carbon, or soot, falls on the glaciers, reducing reflectivity and increasing heat build-up.

This latest study of glacier melt and water flows, appearing in the journal Nature Climate Change, was carried out by scientists at Future Water, a Netherlands-based research group, Utrecht University, and the Nepal-based International Centre for Integrated Mountain Development.

It assesses the contribution of glacier and snowmelt to the region’s river basins, incorporating some of the world’s mightiest rivers – the Indus, the Ganges, the Brahmaputra, the Mekong and the Salween.

The scientists say that highly-sophisticated modelling techniques were used to study the river basins in unprecedented detail.

They report: “Despite large differences in runoff composition and regimes between basins and between tributaries within basins, we project an increase in runoff at least until 2050, caused primarily by an increase in precipitation in the upper Ganges, Brahmaputra, Salween and Mekong basins and from accelerated melt in the upper Indus Basin.

“These findings have immediate consequences for climate change policies where a transition towards coping with intra-annual shifts in water availability is desirable.”

Uncertain supplies

But while the study says that, up to mid-century, little change is likely in the amount of glacier melt water flowing into river basins, it is unclear what will happen thereafter to the water supplies for  what is a significant portion of the world’s population.

“Our study does not include projections after 2050,” Arthur Lutz, lead author of the study, told Climate News Network. “However, at some point in time, the contribution of glacier melt to the total flow will decrease, because of the decreasing glacier extent. When this happens, it will differ for different river basins and sub-basins.”

The study says the long-term outlook is particularly uncertain for the upper Indus basin. While glacier melt contributes only 11.5% of the total runoff in the upper basin of the Ganges river, it contributes more than 40% of total water runoff in the upper Indus basin.

The Indus river, which flows for nearly 2,000 miles from high up in the Hindu Kush-Karakoram Himalaya mountain range down to the Arabian Sea, is vital to life in Pakistan, providing water for 90% of the country’s agricultural crops. Hydro plants along the Indus also supply about half the country’s electricity. – Climate News Network