Polar bears feel the heat as icy habitat shrinks

Polar bears feel the heat as icy habitat shrinks

As climate change increasingly affects the Arctic, some polar bear populations are suffering because rising temperatures are reducing the sea ice vital for their survival.

LONDON, 19 December, 2014 − The Arctic is changing faster under the influence of the warming climate than anywhere else on Earth, scientists have confirmed.

The US National Oceanic and Atmospheric Administration (NOAA) says Arctic air temperatures continue to rise more than twice as fast as they do globally − a phenomenon known as Arctic amplification.

The extent of snow cover in April 2014 in Eurasia was the lowest since 1967, and sea ice extent in September was the sixth lowest since 1979.

Badly affected

Some Arctic polar bear populations have been badly affected by the progressive shrinking of Arctic sea ice.

But NOAA says: “Natural variation remains, such as the slight increase in March 2014 sea ice thickness and only a slight decrease in total mass of the Greenland ice sheet in summer 2014.”

Increasing air and sea surface temperatures, a decline in the reflectivity of the ice at the surface of the Greenland ice sheet, shrinking spring snow cover on land and summer ice on the ocean, and the declining populations and worsening health of some bear populations are among the findings described in NOAA’s Arctic Report Card 2014.

“Arctic warming is setting off changes that affect people and the environment in this fragile region, and has broader effects beyond the Arctic on global security, trade and climate,” Craig McLean, of NOAA, told the annual American Geophysical Union Fall meeting in San Francisco.

“This year’s Arctic Report Card shows the importance of international collaboration on long-term observing programmes that can provide vital information to citizens, policymakers and industry.”

“Arctic warming has broader effects beyond the Arctic on global security, trade and climate”

The Report Card, published annually since 2006, updates changes affecting the Arctic. This year’s report − written by 63 US and other authors − covers key indicators, and also includes a new report on the status of the bears.

This section, written by the Norwegian Polar Institute and Polar Bears International, assesses the animals’ populations in some areas where there is good long-term data available. There are clear variations between areas.

Ice break-up

The most recent data shows that a population decline in western Hudson Bay, Canada, was caused by earlier sea ice break-up and later freeze-up.

The bears depend on sea ice to travel, hunt, mate and, in some areas, to den. But in the southern Beaufort Sea, north of Alaska, their numbers have now stabilised after a decline of about 40% since 2001.

In the Chukchi Sea, between Alaska and Russia and immediately to the west of the Beaufort, the condition of the bears and their reproductive rates have been stable for 20 years.

The Report Card says there are now twice as many ice-free days in the southern Beaufort as there are in the Chukchi Sea.

It notes that polar bears have been through “long and dramatic periods of population decline” during the last million years, and that during periods with little sea ice, polar bears and brown bears have often interbred.

The report says Alaska recorded temperature anomalies more than 10°C higher than the January average during 2014.

Snow cover across the Arctic during the spring was below the long-term average for 1981-2010, with a new record low set in April for Eurasia. North America’s June snow extent was the third lowest on record.

Snow disappeared three to four weeks earlier than normal in western Russia, Scandinavia, the Canadian sub-Arctic and western Alaska because of below-average accumulation and above-normal spring temperatures.

The eight lowest sea ice extents since 1979 have occurred in the last eight years (2007-2014). There is still much less of the oldest, thickest (greater than 13 feet, or four metres) and most resilient ice than in 1988, when it made up 26% of the ice pack. This year’s figure is 10%.

Extent of melting

As sea ice retreats in summer, sea surface temperature across the Arctic Ocean is increasing. In the Chukchi Sea, it is increasing at 0.5°C per decade.

Melting occurred across almost 40% of the surface of the Greenland ice sheet in summer 2014. For 90% of the summer, the extent of melting was above the long-term average for 1981-2010.

In August 2014, the reflectivity (albedo) of the ice sheet was the lowest recorded since satellite observations began in 2000. When less of the sun’s energy is reflected by ice, melting increases. The total mass of the ice sheet remained essentially unchanged between 2013 and 2014.

Declining sea ice allows more sunlight to reach the upper layers of the ocean, triggering increased photosynthesis and greater production of phytoplankton − the tiny marine plants that form the base of the food chain for fish and marine mammals. − Climate News Network

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Sea urchins refine survival instincts as oceans change

Sea urchins refine survival instincts as oceans change

As climate change adds to the threat of extinction faced by many species, new research shows how sea urchins can adapt to the increasing temperature and levels of acidity in Antarctic waters.

LONDON, 17 December, 2014 − The sea urchins of the Southern Ocean could be safe from the threat of extinction. They may not enjoy global warming and the increasingly acid oceans, but new research indicates that they can adapt to climate change.

Researchers from the British Antarctic Survey and Bangor University in Wales − in what they describe as the largest study of its kind − collected 288 urchins of the species Sterechinus neumayeri from waters off the Antarctic Peninsula, carried them to Cambridge in the UK, and tested them in aquarium tanks over a two-year span, covering two full reproductive cycles.

During this time, they report in the Journal of Animal Ecology, they changed the water chemistry and turned up the temperature. The environment was made less alkaline and the thermometer notched up another 2°C − which are the conditions sea creatures could expect by 2100 if the world goes on burning fossil fuels and pumping greenhouse gases under the notorious business-as-usual scenario.

Intricate network

Research like this matters because it helps scientists to better understand the intricate network of environmental conditions that underwrite life on the planet, and because it provides answers to one of the big questions of climate change: how will it affect the estimated seven million species with whom humans share the planet?

According to the journal Nature, the lowest estimate is that 10 species become extinct every week, and the number could be as high as 690 a week. The uncertainty is an indicator of how little is known about the diversity of life on the planet.

The oceans, in particular, have been hard hit by human action. Other marine survival studies have not been encouraging: ocean acidification promises to be very bad news for corals, and therefore for the rich and diverse communities that depend on coral reefs. It also offers a survival threat to bivalves that exploit ocean chemistry to build protective shells.

Other experiments have shown that it can affect the survival behaviour of fish, and can even affect the lugworms that anglers favour as bait for fish.

But the news from the laboratory aquarium in Cambridge is encouraging. It took the sea urchins six to eight months to acclimatise and adjust to the new acidity levels and temperature − but they survived.

Artificial insemination experiments suggested that the urchins could spawn successfully under the new conditions, but to be sure of this, the researchers need more time. Antarctic invertebrates mature very slowly and sea urchins could live for 40 years or more.

“With predictions of warmer, more acidic waters in the future, this work shows how resilient these animals are to climate change,” said Melody Clark, project leader for the Adaptations and Physiology Group at the British Antarctic Survey.

“It also emphasises the importance of conducting long-term experiments in making accurate predictions. These animals live a long time, and so they do everything really slowly. They take around eight months to get used to new conditions, and two years to produce gonads (sexual organs). If we had stopped this experiment at three or even six months, we would have got very different results.”

Change habitat

Sea urchins cannot easily change their habitat: they must adapt or perish. But four-legged, warm-blooded terrestrial creatures have another option. In another instance of long-term research, scientists have established that small mountain mammals are prepared to move uphill as the climate warms.

Karen Rowe, biodiversity research fellow at Museum Victoria in Melbourne, Australia, and colleagues report in Proceedings of the Royal Society that they looked at records of observations of small mammals, made between 1911 and 1934 at 166 sites in the Californian mountains. Then, between 2003 and 2010, they surveyed the same species in the same locations.

Warmer winters are bad for hibernating mammals such as the chipmunk. Image: Vlad Lazarenko via Wikimedia Commons

Warmer winters are bad for hibernating mammals such as the chipmunk.
Image: Vlad Lazarenko via Wikimedia Commons

Altogether, they looked at 30,000 observations that recorded the foraging and breeding ranges of 34 species of chipmunk, gopher, pika, shrew, deer mouse, woodrat and squirrel at altitudes that varied from sea level to about 4,000 metres.

Moving uphill

Since the first, historic set of systematic measurements, the average temperatures in the region have climbed by 0.6°C, and many mammals have shifted their range accordingly – by moving uphill.

The pattern wasn’t consistent, but the researchers identified a problem for those animals that normally hibernate: warmer winters could be very bad news for creatures adapted to the chillier mountain slopes. And those animals that live at the highest altitudes might soon have nowhere to go.

“While mammals can avoid heat stress by behavioural means (such as shifting daily activity), warming winters lead to increased energy expenditures for hibernators and reduce the snow layer, which acts as insulation for non-hibernators,” they conclude.

“Global climate projections suggest that disappearing climates will be an increasing challenge for predicting future species’ responses.” – Climate News Network

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Climate change’s threat of space centre invasion

Climate change's threat of space centre invasion

Rising sea levels and repeated storm damage to natural coastal defences pose an increasing threat to the famous Cape Canaveral rocket launch site in Florida.

LONDON, 15 December, 2014 − Climate change has begun to make its mark on one of America’s most iconic sites – the Kennedy Space Centre at Cape Canaveral in Florida.

Within a decade, according to geologists, the combination punch of rising sea levels and increasing wave energy could start to affect operations at the site where, more than five decades ago, astronauts were launched towards a landing on the Moon.

Peter Adams and John Jaeger, of the University of Florida, have since 2009 been studying the dunes and the beach at Cape Canaveral that historically screened the launch site from even the worst tropical storms.

These dunes were levelled in 2008 during Tropical Storm Fay, in 2011 during Hurricane Irene, and again in 2012 during Hurricane Sandy.

Washed away

Storm waves repeatedly covered a stretch of railroad track built by the US space agency NASA during the 1960s. The line is no longer used, and part of it has been removed to make room for a protective man-made dune. NASA’s own prediction in 2010 was that the line could be permanently breached by 2016.

Hurricane Sandy, the superstorm  that brought catastrophic flooding to New York and caused damage along almost all the US Atlantic seaboard, washed away a section of Cape Canaveral shoreline so close to a US Air Force launch pad that the surrounding fence was left near collapse.

“When you put immovable infrastructure right next to a dynamic environment, something has to give”

Coastal erosion is an enduring fact of life, but during the 1960s the Cape seemed a secure site for one of the great 20th-century adventures.

The two geologists, working as partners with NASA and the US Geological Survey, began looking at a problem that seemed to have been getting worse since 2004: chronic erosion of a six-mile stretch between the two launch pads used for the Apollo missions and space shuttle launches.

According to Dr Adams, the slow rise in sea levels and the increased energy of the ocean’s storm waves – both symptoms of global warming – are almost certainly to blame. He said: “Is it affecting NASA’s infrastructure? The answer’s yes.”

Although man-made dunes will protect the site for the immediate future, the space agency has already spoken of a “managed retreat”. And Dr Jaeger  said: “When you put immovable infrastructure right next to a dynamic environment, something has to give.”

Evidence of flooding

As a coastal facility, Cape Canaveral is naturally vulnerable to hurricanes, which tend to lose their energy as they hit the coasts. But University of Iowa scientists report in the Bulletin of the American Meteorological Society that they have found evidence of flooding by tropical cyclones as far inland as Iowa, in the Midwest.

Gabriele Villarini, a civil and environmental engineer, found the evidence in 30 years’ worth of discharge records from more than 3,000 US Geological Survey stream measurement stations.

Between 1981 and 2011, the US was hit by more than 100 tropical cyclones or hurricanes that did their worst damage at the coast, but could also be linked with major flooding far inland.

“Our results indicate that flooding from tropical cyclones affects large areas of the US and the Midwest, as far inland as Illinois, Wisconsin and Michigan,” Villarini said. – Climate News Network

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Deep concern over invisible threat to Antarctic glaciers

Deep concern over invisible threat to Antarctic glaciers

As ocean temperatures rise, warmer currents are attacking the Antarctic ice sheet from below and adding to the threats posed by a melting rate that has trebled in the last two decades.

LONDON, 13 December, 2014 − The Antarctic ice shelf is under threat from a silent, invisible agency – and the rate of melting of glaciers has trebled in the last two decades.

The ocean waters of the deep circumpolar current that swirl around the continent have been getting measurably warmer and nearer the ocean surface over the last 40 years, and now they could be accelerating glacier flow by melting the ice from underneath, according to new research.

And a separate study reports that the melting of the West Antarctic glaciers has accelerated threefold in the last 21 years.

Calamitous consequences

If the West Antarctic ice sheet were to melt altogether – something that is not likely to happen this century – the world’s sea levels would rise by 4.8 metres, with calamitous consequences for seaboard cities and communities everywhere.

Researchers from Germany, Britain, Japan and the US report in Science journal that they base their research on long-term studies of seawater temperature and salinity sampled from the Antarctic continental shelf.

This continued intrusion of warmer waters has accelerated the melting of glaciers in West Antarctica, and there is no indication that the trend is likely to reverse.

Other parts of the continent so far are stable – but they could start melting for the first time.

“The Antarctic ice sheet is a giant water reservoir,” said Karen Heywood, professor of environmental sciences at the University of East Anglia, UK. “The ice cap on the southern continent is on average 2,100 metres thick and contains 70% of the world’s fresh water. If this ice mass were to melt completely, it could raise global sea level by 60 metres. That is not going to happen, but it gives you an idea of how much water is stored there.”

“These waters have warmed . . . and  are significantly shallower than 50 years ago”

Temperatures in the warmest waters in the Bellinghausen Sea in West Antarctica have risen from 0.8°C in the 1970s to about 1.2°C in the last few years.

“This might not sound much, but it is a large amount of extra heat available to melt the ice,” said Sunke Schmidtko, an oceanographer at the Geomar Helmholtz Centre for Ocean Research in Kiel, Germany, who led the study. “These waters have warmed in West Antarctica over 50 years. And they are significantly shallower than 50 years ago.”

The apparent rise of warm water, and the observed melting of the West Antarctic ice shelf, could be linked to long-term changes in wind patterns in the southern ocean. Although melting has not yet been observed in other parts of the continent, there could be serious consequences for other ice shelves.

The shelf areas are where the Antarctic krill – the little shrimp that plays a vital role in the Antarctic ocean food chain – are getting warmer, with unpredictable consequences for spawning cycles, and then for ocean biodiversity.

Meanwhile, according to US scientists writing in Geophysical Research Letters, the glaciers of the Amundsen Sea in West Antarctica are shedding ice faster than any other part of the region.

Tyler Sutterley, a climate researcher at the University of California Irvine, and NASA space agency colleagues used four sets of observations to confirm the threefold acceleration.

They took their data from NASA’s Gravity Recovery and Climate Experiment (GRACE) satellites, from a NASA airborne project called Operation IceBridge, from an earlier satellite called ICESat, and from readings by the European Space Agency’s Envisat satellite.

Loss calculated

The observations spanned the period 1992 to 2013 and enabled the researchers to calculate the total loss of ice, and also the rate of change of that loss.

In all, during that period the continent lost 83 gigatonnes, or 83 billion metric tonnes, of ice per year on average. Since Mount Everest weighs an estimated 161 billion tonnes, this is as if the ice cap lost an Everest’s worth of ice every two years.

After 1992, the rate of loss accelerated by 6.1 billion tonnes a year, and between 2003 and 2009 the melt rate increased by 16.3 gigatonnes a year on average. So the increasing rate of loss is now nearly three times the original figure.

“The mass loss of these glaciers is increasing at an amazing rate,” said Isabella Velicogna, Earth system scientist at both UC Irvine and the NASA Jet Propulsion Laboratory. – Climate News Network

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Scientists hammer out warning on climate change risks

Scientists hammer out warning on climate change risks

A group of international experts says time is rapidly running out to take serious steps to avert the impacts of global warming by prioritising a switch to clean energy systems.

LONDON, 4 December, 2014 − The all-too-familiar story of ice loss in the world’s polar regions, repeated over and over by researchers in the last two years, is being told yet again – this time for the benefit of delegates at the UN climate change conference currently being held in Lima, Peru.

A report in Earth’s Future journal by distinguished scientists from an international group called Earth League aims to remind the delegates that time is running out to avert the serious impacts of climate change.

Each summer, most of the surface of Greenland now starts to melt – and to darken, which means it absorbs more light, and becomes increasingly more likely to go on melting.

The same thing is happening in the Arctic Ocean, where open sea is now absorbing radiation that would once have been reflected by sea ice.

Irreversible melting

In West Antarctica, a warming ocean has begun to advance, and the glacial ice to retreat, which means more loss of ice, and more warming, and more retreat. With this retreat comes the first sign of irreversible melting in some parts of the ice sheet.

The snows of the Greenland ice sheet alone hold enough water to raise sea levels by seven metres or more. But the retreat of the ice in the Arctic quite literally opens up new territory for another feedback: as permafrost thaws it will release tens of thousands of years of stored carbon, to stoke up greenhouse gas levels and trigger yet more warming.

There is still a chance that humanity can take steps and limit global average temperature rise to 2°C, but the current rates of greenhouse gas emissions could push temperatures to an average of 4°C or more above the averages at the start of the Industrial Revolution by the end of the century.

“Our climate would be as different from pre-industrial conditions as it was when the Earth began to emerge from the last ice age”

“If this occurs,” the Earth League scientists warn, “our climate would be as different from pre-industrial conditions as it was when the Earth began to emerge from the last ice age some 18,000 to 20,000 years ago.”

They add:  “Considerable risks, with potentially serious impacts, are already expected at 1°C to 2°C warming, which will require large investments in adaptation.”

If the temperatures rise beyond the 2°C target, societies will experience increasing risks from extreme events, along with other changes that could make several parts of the world “susceptible to extremely high social and economic costs.

This includes risks to global food production, freshwater supply and quality, significant sea level rise, changes in disease patterns and possibly higher risk of pandemics.”

All this, too, has been said before. But the fact that a group of scholars, economists, geographers and meteorologists from distinguished universities, institutes, academies and laboratories in Europe, the US, Mexico, Brazil and India felt the need to say it once more, with feeling, is an indicator of the urgency of the problem.

Greater risk

As things stand, they say, there is a 30% probability that global average temperatures will exceed 2°C by the end of the century. This is a risk “much greater than we normally accept for other potentially dangerous societal risks, such as nuclear power generation, terrorism, and human health epidemics”.

The report’s authors point out that change is possible, and that a global energy revolution has already begun. Energy demand is many developed countries is falling, and renewable energy use increasing.

“The world may be approaching a point,” they say, “where the technological feasibility and economic benefits clearly tip in favour of a large-scale transition to an economy powered by clean and efficient energy.”

However, they warn that these changes can only happen “by prioritising access to cheap modern energy systems and higher mitigation requirements on richer nations who have caused the bulk of CO2 emissions from fossil fuels so far”. – Climate News Network

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Ocean heat drives surge to global warming record

Ocean heat drives surge to global warming record

Climate scientists say this year looks likely to enter the record books as the world’s hottest, with the warming of the oceans causing striking changes.

LONDON, 3 December 2014 − It’s official, even though it won’t be conclusive for a few months yet: if present trends continue, 2014 will be one of the hottest years on record − and quite possibly the hottest of them all.

Preliminary estimates by the World Meteorological Organisation (WMO) − published to provide information to the UN Framework Convention on Climate Change annual round of negotiations, currently being held in Lima, Peru − show this year is set to be a record breaker largely because of record high global sea surface temperatures.

These, combined with other factors, helped to cause exceptionally heavy rainfall and floods in many countries and extreme drought in others.

Christiana Figueres, executive secretary of the Convention, said: “Our climate is changing, and every year the risks of extreme weather events and impacts on humanity rise.”

Above normal

It is the warming of the oceans − which the WMO says “will very likely remain above normal until the end of the year” − that is chiefly perplexing the scientists.

The WMO’s provisional statement − to be finalised in March next year − on the Status of the Global Climate in 2014 shows that the global average air temperature over the land and sea surface from January to October was about 0.57°C above the average of 14°C for the 1961-1990 reference period, and 0.09°C above the average for 2004 to 2013.

If November and December follow the same trend, the WMO says, then 2014 will probably be the hottest on record, ahead of 2010, 2005 and 1998. This confirms the underlying long-term warming trend.

“The provisional information for 2014 means that 14 of the 15 warmest years on record have all occurred in the 21st century,” said the WMO secretary-general, Michel Jarraud. “There is no standstill in global warming.

“Record-breaking heat, combined with torrential rainfall and floods, destroyed livelihoods
and ruined lives”

“What we saw in 2014 is consistent with what we expect from a changing climate. Record-breaking heat, combined with torrential rainfall and floods, destroyed livelihoods and ruined lives. What is particularly unusual and alarming this year are the high temperatures of vast areas of the ocean surface, including in the northern hemisphere.

“Record-high greenhouse gas emissions and associated atmospheric concentrations are committing the planet to a much more uncertain and inhospitable future.”

Weather patterns

The high January to October temperatures occurred in the absence of a full El Niño-Southern Oscillation (ENSO). An ENSO occurs when warmer than average sea-surface temperatures in the eastern tropical Pacific combine, in a self-reinforcing loop, with atmospheric pressure systems, affecting weather patterns globally.

Among the remarkable features of 2014’s first 10 months are land surface temperatures. The WMO says they averaged about 0.86°C above the 1961-1990 average, the fourth or fifth warmest for the same period on record.

Global sea-surface temperatures were unequivocally the highest on record, at about 0.45°C above the 1961-1990 average. Temperatures were particularly high in the northern hemisphere from June to October for reasons, the WMO notes, that “are subject to intense scientific investigation”.

The ocean heat content for January to June was estimated to depths of 700m and 2000m, and both were the highest recorded. Around 93% of the excess energy trapped in the atmosphere by greenhouse gases from fossil fuels and other human activities ends up in the oceans, so the heat they contain is essential to understanding the climate system.

The early part of 2014 saw global-average measured sea level reach a record high for the time of year. Arctic sea-ice extent was the sixth lowest on record, according to the National Snow and Ice Data Centre, in the US, but Antarctic daily sea ice reached a new record for the third consecutive year.

Some impressively anomalous rainfall and floods made 2014 a year to forget as fast as possible. The UK winter was the wettest on record, with 177% of the long-term average precipitation. In May, devastating floods in south-east Europe affected more than two million people, and in Russia, in late May and early June, more than twice the monthly average precipitation fell in parts of southern Siberia.

In September, southern parts of the Balkan peninsula received over 250% of the monthly average rainfall, while parts of Turkey had more than 500%. Heavy rains caused severe flooding in northern Bangladesh, northern Pakistan and India, affecting millions of people.

Searing drought

In contrast, parts of north-east China, large areas of the western US, Australia, and Brazil experienced searing drought.

But the incidence of tropical storms and cyclones recorded was lower than the 1981-2010 average in much of the world.

The WMO Global Atmosphere Watch Programme shows that atmospheric levels of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) reached new highs in 2013  − the most recent data processed to date.

Globally-averaged atmospheric levels of CO2 reached 396.0 parts per million (ppm), approximately 142% of the pre-industrial average. The increase from 2012 to 2013 was 2.9 ppm, the largest year to year increase.

Atmospheric CH4 concentrations reached a new high of 1,824 parts per billion (ppb) in 2013, about 253% of the pre-industrial level, and concentrations of N2O reached 325.9 ± 0.1 ppb, a rise of 121%. − Climate News Network

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Yellow submarine is a big hit for Antarctic records

Yellow submarine is a big hit for Antarctic records

A new underwater robot is revolutionising important research into the thickness of the sea ice floating off Antarctica’s coasts by looking up from the depths to create detailed 3-D maps.

LONDON, 27 November, 2014 − For the first time, researchers have begun to collect accurate data on the thickness of the sea ice around Antarctica.

A new underwater robot called SeaBED has begun to deliver a clear picture of the greatest mass of floating frozen water on the planet. And the first evidence is that the ice is thicker than anyone had realised: on average somewhere between 1.4 and 5.5 metres, but sometimes as much as 16 metres or more.

Although scientists can keep an eye on the precise extent of the seasonal ice, thanks to consistent satellite data, looking beneath the rim of floating ice that surrounds the enormous continent has been more of a problem. But it’s a problem SeaBED is now addressing by producing the first detailed, high-resolution 3-D maps of Antarctic sea ice.

Baseline measurement

Ice thickness measurements are not easy. During the Cold War, nuclear submarines routinely cruised under the Arctic Ocean ice, making measurements – for navigational safety reasons, rather than climate research. But, in consequence, when the Arctic ice sheet started to melt and dwindle, researchers had a baseline of accurate measurement.

The Antarctic, however, is a partly-submerged rocky continent that bears a huge burden of snow and ice. Shipboard and shore-based studies can provide only a limited set of measurements of ice thickness off its coasts.

Now Guy Williams, a polar oceanographer at theUniversity of Tasmania Institute for Marine and Antarctic Studies, and colleagues from the British Antarctic Survey  and other institutions, report in Nature Geoscience that at last they have a clearer picture of the ice thickness, and therefore a better chance of calculating how sea ice is likely to change as the planet’s climate continues to warm.

“We can now measure in far greater detail, and were excited to measure ice up to 17 metres thick”

SeaBED, technically described as an autonomous underwater vehicle (AUV), is a little yellow submarine two metres long and weighing 200 kg. It was designed and built by the Woods Hole Oceanographic Institution in the US.

In 2010 and 2012 it made a series of autonomous underwater traverses in lawnmower fashion, at depths of 20-30 metres. Most surveying instruments look down, but this one looks up at the ice above it.

There has been a level of alarm at change in Antarctica in recent years. Although the sea ice during recent polar winters has been greater than ever there has been concern about the rate at which some Antarctic glaciers are melting − with worrying consequences for the rate of sea level rise.

Accurate estimates

So the more accurate the information about the volumes of ice formed and lost, the more accurate the estimates of future sea level rise, and the better the understanding of the polar climate machinery.

The AUV measurements – especially when backed up by direct measurements, radar and satellite studies – promise to provide a real insight into the nature of Antarctic sea ice.

Jeremy Wilkinson, lead investigator at the British Antarctic Survey, says: “We can now measure in far greater detail, and were excited to measure ice up to 17 metres thick.”

David Ferreira, an oceanographer at the University of Reading, who is not one of the authors, called the study “a formidable benchmark” in formulating climate models of the region.

“We strongly depend on the simulation of the sea ice in these models to test possible causes of the Antarctic sea ice expansion,” he said. “Effects of the ozone hole, of melt water from the Antarctic ice sheet, or of sea ice movements are among the plausible candidates, but we are limited by the quality of our models in this poorly-observed region of the world to discriminate between them.” – Climate News Network

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Weather extremes will be the norm as world warms

Weather extremes will be the norm as world warms

The World Bank says the Earth is on an unavoidable path towards a 1.5˚C heat rise by mid-century – but it could reach 4˚C by 2100 unless immediate action is taken to avoid dire impacts for millions of people.

LONDON, 26 November, 2014 − As the planet continues to warm, heat waves and other weather extremes that happen perhaps once in hundreds of years − if ever − would become the “new climate normal”, a World Bank report says.

The consequences for development would be severe: failing harvests, shifting water resources, rising sea-levels, and millions of people’s livelihoods put at risk.

The World Bank report, the third in its Turn Down the Heat series, says even very ambitious mitigation action taken today will not stop global average temperatures reaching about 1.5˚C above their pre-industrial level by the middle of this century. They are already 0.8˚C higher, and likely − on present trends − to reach about 4˚C by 2100.

Poor and vulnerable

“Today’s report confirms what scientists have been saying – past emissions have set an unavoidable course to warming over the next two decades, which will affect the world’s poorest and most vulnerable people the most,” said Jim Yong Kim, President of the World Bank Group.

“We’re already seeing record-breaking temperatures occurring more frequently, rainfall increasing in intensity in some places, and drought-prone regions like the Mediterranean becoming drier. These changes make it more difficult to reduce poverty. . . They also have serious consequences for development budgets.”

“Tackling climate change is a matter of reason,
but also of justice”

The report was prepared for the Bank by the Potsdam Institute for Climate Impact Research (PIK), and the UK independent thinktank, the Overseas Development Institute.

The report’s lead author, Professor Hans Joachim Schellnhuber, director of PIK, said: “Tackling climate change is a matter of reason, but also of justice. Global warming impacts in the next decades are likely to hit those hardest that contributed least to global greenhouse gas emissions: the global poor.”

Chain of impacts

Dr Bill Hare, founder and CEO of the Berlin-based not-for-profit organisation, Climate Analytics, is another lead author of the report. He said: “Assessing the entire chain of climate impacts − for example, how heat waves trigger crop yield declines, and how those trigger health impacts − is key to understanding the risks that climate change poses to development.”

Many of the worst projected impacts can still be avoided by holding warming below 2˚C, the report says. It analyses the probable impacts of 0.8˚C, 2˚C and 4˚C of extra heat on agricultural production, water resources, ecosystem services and coastal vulnerability across Latin America and the Caribbean, the Middle East and North Africa, and parts of Europe and Central Asia.

A common threat across the three regions is the risk posed by heat extremes. State-of-the-art climate modelling shows that “highly unusual” extremes − similar to the heat waves in the US in 2012 and in Russia and Central Asia in 2010 − would increase rapidly under a 4˚C emission pathway. It also shows that the risks of reduced crop yields and production losses increase significantly above 1.5˚C to 2˚C.

Key findings across the regions include:

  • Latin America and the Caribbean: Heat extremes and changing rainfall will damage harvests, water supplies and biodiversity. In Brazil, without further adaptation, crop yields could decrease by 2050 by up to 70% for soya and 50% for wheat with 2˚C of warming. Ocean acidification, sea level rise, cyclones and temperature changes will affect coastal livelihoods, tourism, health, food and water security, particularly in the Caribbean.
  • Middle East and North Africa: A large increase in heat waves, combined with warmer average temperatures, will put intense pressure on already scarce water resources, seriously affecting human consumption and regional food security. In Jordan, Egypt, and Libya, harvests could fall by up to 30% with 1.5˚ to 2˚C warming by 2050. Migration and climate-related pressure on resources may increase the risk of conflict.
  • Western Balkans and Central Asia: Melting glaciers and shifts in the timing of water flows will lead to less water resources in summer months and high risks of torrential floods in Central Asia. In the Balkans, a higher drought risk will affect harvests, urban health and energy generation. In Macedonia, yield losses are projected of up to 50% for maize, wheat, vegetables and grapes at 2˚C warming by 2050.

The report adds that forest damage and thawing permafrost in northern Russia could release carbon and methane. With 2˚C warming by 2050, methane emissions could increase by 20% to 30% across Russia. − Climate News Network

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Rare water data drives heating debate underground

Rare water data drives heating debate underground

Global warming’s effects are being felt even below the Earth’s surface, as researchers find that temperatures are rising not only in oceans, but also in subterranean freshwater sources.

LONDON, 25 November, 2014 − Two great bodies of water have begun to feel the heat. European scientists report that they have evidence that the planet’s groundwater – the subterranean ocean of freshwater that bubbles into wells, freshens desert springs, scours great underground limestone caverns and makes possible the irrigation of crops in the world’s farmlands – may be responding to climate change.

And out on the open sea, average global surface temperatures in the northern summer of 2014 were the highest ever recorded.

Both claims will require verification from other sources: in science, one set of measurements is never enough.

Precious resource

In the case of the groundwater temperature rises, this will not be easy. Although water authorities everywhere are concerned about the depletion of this precious resource, and there are routine chemical and microbiological checks, sustained records of groundwater temperatures are rare.

But a team from ETH Zurich in Switzerland and Karlsruhe Institute of Technology in Germany had an advantage: they had data from four wells near the German cities of Cologne and Karlsruhe, where temperature records have been maintained systematically for nearly 40 years.

They report in the journal Hydrology and Earth System Sciences that, after a detailed study of evidence from the four sources, they were able to identify a pattern of very small but significant rises in the groundwater temperatures that mirrored – but came later than – changes in average temperatures above ground. That is, even far below the surface, global warming is making its presence felt.

Research like this is not easy, and there will be plenty of questions and some argument about how they reached these conclusions.

Warming stages

Groundwater is ancient rainfall that seeped down into the bedrock and filled the pores in the soil. As it is drawn from one source, it moves to fill the gap, so there will be questions about how “old” the water is, how swiftly it is being replenished, how well insulated it is from the surface, and how close it might be to seepage from surface rivers.

However, the data reveals not just a rise in temperatures over the four decades, but also a series of warming stages that echo patterns of warming in the atmosphere far above.

“Global warming is reflected directly in the groundwater, albeit damped and with a certain time lag,” says Peter Bayer, senior scientist in engineering geology at ETH Zurich.

Meanwhile, Axel Timmermann, professor of oceanography at the University of Hawaii’s International Pacific Research Centre, says that global mean sea surface temperatures in 2014 were the highest ever recorded.

They were higher even than those of 1988, a year marked by a powerful El Niño event that warmed the Pacific and reversed climate patterns, with sometimes catastrophic consequences in the form of floods, droughts, windstorms, forest fires and harvest failures.

Unexpected slowdown

The 2014 ocean warming may have brought to an end the so-called global warming hiatus, in which average surface air temperatures rose only very slowly between 2000 and 2013.

While there have been a number of possible explanations for this unexpected slowdown – unexpected because greenhouse emissions have increased in that time – there has been no clinching argument. But Timmerman says that the long pause may have come to an end.

He says: “The 2014 global ocean warming is mostly due to the North Pacific, which has warmed far beyond any recorded value and has shifted hurricane tracks, weakened trade winds and produced coral bleaching in the Hawaiian islands.

“Record-breaking greenhouse gas concentrations and anomalously weak North Pacific summer trade winds, which usually cool the ocean surface, have contributed further to the rise in sea surface temperatures. The warm temperatures now extend in a wide swath from just north of Papua New Guinea to the Gulf of Alaska.” – Climate News Network

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Iron’s mixed blessing for health of oceans

Iron’s mixed blessing for health of oceans

New research shows that iron fertilisation stimulates growth of the plankton that help transport carbon dioxide to the deep ocean – but swells the number of small creatures who feed on plankton and whose shells put CO2 back into the atmosphere.

LONDON, 16 November, 2014 − Technology’s answer to climate change in a world in which humans go on releasing carbon dioxide in the atmosphere has just had another setback. The idea of fertilising the planet’s oceans with iron filings to stimulate green growth and turn the oceans into a carbon sink isn’t so simple as hoped.

Two studies – both involving experiments at sea – have confirmed that trace elements such as iron affect plankton growth, and that more iron can mean more carbon dioxide exported to the sea bed in the form of dead and buried life forms. But new research in Nature Geoscience shows that the story is more complex.

Ian Salter, bioscience researcher at the Alfred Wegener Institute’s Helmholtz Centre for Polar and Marine Research, Germany, and colleagues report that they took a closer look at what happens around the Crozet Islands in the Southern Ocean − basaltic islands that deliver a steady natural supply of iron to the surrounding waters.

Carbon pumped

More iron meant more phytoplankton, which meant that more carbon was pumped into deeper waters. But more phytoplankton also meant more little creatures such as foraminifera, which graze on phytoplankton, and then make shells of calcium carbonate − a process that puts carbon dioxide back into the atmosphere.

Dr Salter and his colleagues estimate that the carbonate manufacture in waters naturally fertilised by iron reduced the overall amount of carbon transferred to the deep ocean by between 6% and 32%, whereas in waters not fertilised by iron, the reduction was 1% to 4%. So added iron might make the phytoplankton grow, but it also soups up the return of carbon dioxide to the atmosphere.

The finding is not conclusive. It doesn’t settle the question of whether the presence of trace iron ultimately assists the removal of more carbon from the atmosphere in the long term.

It also doesn’t answer questions about how things might work in warmer waters, and doesn’t offer a guide to the overall effect of iron deliberately added to waters where the phytoplankton don’t bloom in profusion.

“We are in the middle of an experiment we cannot reverse, but which we still don’t understand . . .”

But it does provide a snapshot of science in action, and is yet another reminder that the climate system – and especially the traffic in carbon between rock, water, air and living tissue – is immensely complex, and still puzzling.

And if that wasn’t already clear, new research in the Proceedings of the National Academy of Sciences confirms that there is a lot more to be learned about the role of oceans in climate science.

Researchers report that ocean temperatures have been far more variable over the last 7,000 years than anyone had realised.

Thomas Laepple, a climate scientist at the Alfred Wegener Institute, and Peter Huybers, Professor of Earth and Planetary Sciences at Harvard University, US, combed the climate archives, examined indirect evidence from sediment cores and corals and other sources, and reconstructed sea surface temperatures in a range of different locations over a period of thousands of years.

Then they picked 20 climate models and conducted more than 100 test runs to see if they could simulate the same pronounced fluctuations in ocean temperatures in the same places over the same timescale

Greater discrepancies

They could − but only for short periods. The longer the time sequence, the greater the discrepancies. Over timescales of a thousand years, the models underestimated the variations by a factor of 50.

“Fundamentally, there are only two explanations,” Dr Laepple says. “Either the climate archives do not provide reliable temperature data, or the climate models underestimate the variability of the climate. Or both may be true to some extent.”

Neither finding suggests that climate scientists don’t know what they are doing. In fact, quite the reverse: researchers are establishing just what they can be sure about, and what remains uncertain.

Nor does either finding suggest that long-term alarm over the consequences of increasing levels of atmospheric carbon dioxide is based on uncertain science.

Dr Laepple says: “We are in the middle of an experiment we cannot reverse, but which we still don’t understand well enough to make clear statements at the regional level on longer timescales. Unfortunately, we will just have to continue with this uncertainty for some time.” – Climate News Network

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