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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Obama pledge gets dollars flowing into climate fund

Obama pledge gets dollars flowing into climate fund 

Many developing countries are already suffering the impacts of climate change, but a special fund to help them adapt to a warming world has been bolstered by promises of billions of dollars from wealthier nations.

LONDON, 20 November, 2014 − It’s been quite a week for those waiting for some action on climate change.

After US President Obama and China’s President Xi Jinping announced radical plans to cut back on greenhouse gas emissions, Obama then called on nations at the G20 summit in Brisbane, Australia, to agree to a new deal on climate.

And when he backed that up by pledging US$3 billion to the Green Climate Fund (GCF), set up in 2010 to promote low emissions and climate-resilient projects in the developing world, other countries quickly reached for their cheque books.

Paying their dues

Japan says it will be giving $1.5 billion to the GCF. Britain indicated it will be pledging a similar amount.  France and Germany have already announced they will be giving the $1 billion each. Sweden is pledging more than $500 million. And other countries in the developed world are lining up to pay their dues.

The GCF, which operates under the auspices of the United Nations Framework Convention on Climate Change, is holding a special High-Level Pledging Conference in Berlin today.

“This week’s announcements will be a legacy of US President Obama,” said Hela Cheikhrouhou, GCF’s executive director. “It will be seen by generations to come as the game‐changing moment that started a scaling‐up of global action on climate change.”

Obama said money paid into the GCF would help developing countries leapfrog some of the dirty industries that fuelled growth in the industrialised world, and will allow them to build clean-energy economies.

“Along with the other nations that have pledged support, this gives us the opportunity to help vulnerable communities with an early warning system, with stronger defences against storm surge, climate resilient infrastructure, to help farmers plant more durable crops,” Obama said.

In the past, calls for cash to support the Fund’s activities in the developing world have been largely unsuccessful. Now the mood seems to have changed.

“It will be seen by generations to come as the game‐changing moment that started a scaling‐up of global action on climate change”

In the US, the Republicans – who now control both houses of Congress – are for the most part firmly opposed to Obama’s new-found zeal for action on the climate.

The White House feels that public attitudes on climate change issues are changing, both within the US and around the globe, but a brave new, fossil fuel-free world is still a long way off.

There are big questions about how the emissions reductions announced in the US-China agreement are to be achieved.

And the pledges to the GCF look impressive, but leaders of the wealthier nations have a tendency for making grand monetary gestures at international gatherings –then not following through with the cash.

Despite this, climate change has been put firmly among the top items on the international agenda. Momentum has also been built towards achieving a new global deal at the UN Climate Change Conference in Paris late next year.

Clear message

The past week’s events have also sent a clear message to the fossil fuel industry, and to investors in the sector: many of the most powerful countries in the world now agree that greenhouse gas emissions have to be cut.

The message has not gone down well with Tony Abbott, the Australian prime minister, and host of the G20 summit.

Although Australia is considered by scientists to be one of the countries most vulnerable to global warming, the Abbott government has made known its scepticism on the issue and has rolled back various measures aimed at combating changes in climate.

It has also strongly backed the development of several large-scale coal mining operations on the east coast, adjacent to the waters of the Great Barrier Reef. – Climate News Network

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Insurance industry sleeps through climate alarm calls

Insurance industry sleeps through climate alarm calls

Disasters linked to climate change could cost insurance companies billions of dollars, but a new survey finds that many of them − particularly in the US − are paying scant attention to the threat.

LONDON, 30 October, 2014 − Insurance is all about assessing risk, so you might expect companies in the sector to be intimately involved with one of the most potent risks facing the world – the possibility of catastrophic climate change.

Yet a survey by Ceres, a US not-for-profit group that lobbies for more environmental awareness in the business sector, has found a startling lack of action by most insurers on the issue.

In total, more than 300 insurers − a large proportion of them based in the US − were canvassed and then given various ratings associated with their response to climate change –ranging from “leading” to “minimal”.

“Most of the companies responding to the survey reported a profound lack of preparedness in addressing climate-related risks and opportunities,” the Ceres report says. “Only nine insurers, or three per cent of the 330 companies overall, earned a ‘leading’ rating.”

Forecasting techniques

The Ceres survey examined the structures and management that companies have in place to deal with climate change, their forecasting techniques, how they communicate on the issue with policyholders and investors, and how the companies were dealing with their own carbon emissions.

On all counts, the majority of companies were found wanting, with the relatively smaller companies performing less well than the bigger concerns.

The insurance industry is considerably bigger in the US than elsewhere, but only two of the nine companies that earned leading ratings in the survey are based in the US. Non-US companies that gained a leading rating include the re-insurers Swiss Re and Munich Re, and the XL Group.

Property and Casualty insurers are on the frontline of climate change risks, and “there is compelling evidence those risks are growing”

The survey looked in detail at two key segments of the insurance industry: Property and Casualty (P&C), and Life and Annuity (L&A).

Ceres says P&C insurers are on the frontline of climate change risks, “and there is compelling evidence those risks are growing”.

Hurricane Sandy, which hit the Caribbean and the eastern seaboard of the US in late 2012, resulted in $29 billion of insured losses in the US.

“A tremendous amount of property (both insured and uninsured) is increasingly threatened by sea level rise,” Ceres says.

A report earlier this year by CoreLogic, a financial analysis and advisory company, identified more than 6.5 million homes in the US at risk of storm surge damage, with a total reconstruction value amounting to $1.5 trillion.

“Extreme weather is also exacerbating supply chain risks and causing business interruption losses,” Ceres says.

In 2011, there was serious flooding in Thailand, and international companies with manufacturing plants there suffered between $15 billion and $20 billion in losses.

Profit margins

Most P&C insurers pay inadequate attention to climate risks, but the L&A segment of the industry is even more lax, Ceres says. L&A insurers have trillions of dollars worth of investments that may be affected by climate change. If those investments are not managed with climate change in mind, then profit margins will suffer and companies might struggle to meet their liabilities in the long term.

The insurance industry also isn’t paying nearly enough attention to how global warming will affect human health and mortality, Ceres warns. The survey shows that most health insurers are not preparing for climate change-related temperature extremes, decreasing air quality, and the increased spread of diseases.

“As risk carriers, risk managers and major investors, every insurer should develop and issue a public climate risk management policy for the benefit of their shareholders, policy holders and employees,” Ceres recommends.

Separately, the Bank of England, the UK’s central bank, has written to 30 leading insurance companies asking for information on how they assess the impact of climate change-related events on their operations. – Climate News Network

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Sea rise may still pose a man-sized threat

Sea rise may still pose a man-sized threat

Although new research discounts the likelihood of a two-metre sea rise this century, the predicted impacts of global warming are still bad news for the many millions of people living at or near sea level.

LONDON, 21 October, 2014 − For those who think climate change means deep trouble, some comfort: there is a limit to how deep. Danish-led researchers have looked at all the projections and satisfied themselves that, at the very worst, sea levels this century will rise by a maximum 1.8 metres − roughly the height of an average man.

They report in Environmental Research Letters that they contemplated rates of melting in Greenland and Antarctica, the retreat of mountain glaciers worldwide, and the impact of groundwater extraction for agriculture and industry.

They also looked at all the projections for thermal expansion of the oceans, because warmer water is less dense than colder water and therefore occupies a greater volume. Then they began to calculate the band of possibilities.

“We have created a picture of probable limits for how much global sea levels will rise this century,” said Aslak Grinsted, assistant professor in the Niels Bohr Institute’s Centre for Ice and Climate at the University of Copenhagen. “Our calculations show that seas will likely rise by around 80cm. An increase of more than 180 cm has a likelihood of less than 5%. We find that a rise in sea levels of more than 2 metres is improbable.”

Critical infrastructure

The worst-case scenario, he says, is something that it would be wise to consider for critical infrastructure, such as the Delta Works, a series of construction projects that protect a large area of land in the south-west of the Netherlands, or the Thames Barrier, which aims to prevent London from being inundated by exceptionally high tides and storm surges from the North Sea.

The finding comes with two important provisos: one is that any significant rise remains extremely bad news for people in those regions of the planet that are already more or less at sea level − among them the coral atolls of the tropical oceans, the Netherlands, the Nile Delta, Bangladesh, Venice in Italy, and some of the world’s great maritime cities.

The other is that the man-high limit extends only to 2100, and researchers have repeatedly warned that, once begun, sea level rise will continue for centuries.

The Danish calculations fall into the category of things that could happen: melting in polar waters inevitably means even warmer equatorial waters, and another ominous projection for the near future is that commercially valuable fish could desert the tropics by 2050.

William Cheung, head of the Changing Ocean Research Unit at the University of British Columbia, Canada, and Miranda Jones, an environmental scientist at the same university, considered what would happen if the world warmed by 3°C by 2100.

“The tropics will be the overall losers. This area has
a high dependence on fish for food, diet and nutrition”

They report in ICES Journal of Marine Science that, under such a scenario, tropical fish could move away from their present habitats at a rate of 26 kilometres a decade. Even with a 1°C warming, they would desert their home waters at 15 km a decade.

Altogether, the two scientists considered the possibilities for 802 commercially important species, concluding that such a set of migrations might introduce new potential catches in Arctic waters, but could be very bad news for tropical fishermen, and for the hundreds of millions who depend on fish as a source of protein.

“The tropics will be the overall losers,” Dr Cheung said. “This area has a high dependence on fish for food, diet and nutrition. We’ll see a loss of fish populations that are important to the fisheries and communities in these regions.”

Accelerated rates

Paradoxically, as researchers consistently forecast accelerated rates of melting in polar waters, the Antarctic sea ice in September occupied a greater area than ever before, with the five-day average on September 19 reaching 20 million sq km, according to the US National Snow and Ice Data Centre.

That means that while most of the planet continued to warm, the Antarctic continent and the seas around it were icier, for one season at least.

Such measurements ultimately depend on satellite and aerial surveillance, and according to Claire Parkinson, climate change senior scientist at  the NASA Goddard Space Flight Centre, the anomaly simply reflects the complexity of climate dynamics and the diversity of the Earth’s environments.

“The planet as a whole is doing what was expected in terms of warming,” she says. “Sea ice as a whole is decreasing as expected, but just like with global warming, not every location with sea ice will have a downward trend in ice extent.”

But, overall, the planet is still saying goodbye to ice. The Antarctic’s gain is roughly a third in area of the loss of ice in the Arctic. – Climate News Network

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Oceans’ greater heat explains warming ‘pause’

Oceans' greater heat explains warming 'pause'

New technology is helping scientists to re-assess how much heat is being absorbed by the world’s oceans – much more in some regions than realised, they say.

LONDON, 7 October 2014 – One of the most hotly-argued questions in climate research – whether global warming has slowed or even stopped – appears to have been definitively answered. And the scientists’ conclusion is unambiguous: the Earth continues to warm at a dangerous pace.

All that’s happening, they say, is that the extra heat being produced – mainly by the burning of fossil fuels – is concentrating not in the skies but in the seas. They have found new evidence that backs them up.

Instead of driving up the temperature of the atmosphere quite as fast as predicted, the evidence shows that the heat from greenhouse gas emissions is warming the oceans much more rapidly than had been realised.

In some regions the water appears to have been warming, for over 40 years, more than twice as quickly as thought, for instance in the upper 2,300 feet (700 metres) of the southern hemisphere’s oceans.

Paul Durack from the Lawrence Livermore National Laboratory in California and colleagues compared direct and inferred sea temperature measurements with the results of climate models. Together the three sets of measurements suggest estimates of northern hemisphere ocean warming are about right.

Serious under-estimate

But the team report in Nature Climate Change their estimate that warming in the southern seas since 1970 could be far higher than scientists have been able to deduce from the limited direct measurements from this under-researched region. Globally, they conclude the oceans are absorbing between 24 and 58% more energy than thought.

The researchers were able to use data from satellites and from a new source – Argo floats, a fleet of more than 3,000 free-floating monitors which drift through the water and measure the temperature and salinity of the upper 6,500 feet (2,000 m) of the ocean.

A year ago, the Intergovernmental Panel on Climate Change published its Fifth Assessment Report. Professor Chris Rapley, a former director of both the British Antarctic Survey and  the Science Museum in London, told the Climate News Network then of his alarm at what the IPCC said about the oceans.

He said the Earth’s energy imbalance, and evidence that the 93% of the energy build-up absorbed by the oceans continued to accumulate, meant the slow-down in the rise of surface temperatures appeared “a minor and temporary fluctuation”.

Speaking of the latest research, Profesor Rapley told the Network: “The newly reported results of a combination of satellite altimetry measurements of globally mapped sea level rise combined with ocean heat modelling, and a further analysis of the in situ measurements from the Argo buoys, add to the evidence that the so-called ‘pause’ in global warming is confined to surface temperature data, whilst the planet’s energy imbalance continues unabated.

Cold depths

“Once more we need to assess our appetite for risk, and consider seriously what measures we should take to minimise the threats to food and water supplies, the impacts of extreme weather, and the consequences of these to the world economic system and human wellbeing.”

A second study, also published in Nature Climate Change, by scientists at NASA’s Jet Propulsion Laboratory in Pasadena, California, concluded tentatively that all ocean warming from 2005 to 2013 had occurred above depths of 6,500 feet, and that it was not possible to detect any contribution by the deep oceans to sea level rise or energy absorption.

Josh Willis, a co-author of this study (which like that by Dr Durack and his colleagues results from the work of NASA’s newly-formed Sea Level Change Team)  said the findings did not throw suspicion on climate change itself. He said: “The sea level is still rising. We’re just trying to understand the nitty-gritty details.”

This study therefore leaves several questions still unanswered. Will more research find evidence that deep water is in fact warming, for instance? Why are the oceans now apparently absorbing more heat than they once did? And if the southern oceans are heating up faster, then may that help to speed up Antarctic ice melt?

One urgent question that needs answering is how much longer the water near the surface can continue to absorb the extra heat which human activities are producing. Another is what will happen when the oceans no longer absorb heat but start to release it. The answers could be disturbing. – Climate News Network

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Surfers fear climate will wipe out big waves

Surfers fear climate will wipe out big waves

Dedicated surfers, deeply involved with monitoring the natural coastal environment around the world, warn that climate change now poses a major threat to this booming leisure industry.

LONDON, 5 October, 2014 − The world’s oceans are alive with surfers enjoying one of the fastest growing leisure activities. It is estimated there are now at least 35 million people around the globe who regularly ride the waves, and many thousands of people are employed in what has grown into a multi-billion dollar industry.

A warming world should be good news for all those artists of the waves. Warming oceans mean more storms, and the theory goes that more storms will lead to ever bigger waves. So why then are surfing websites – the internet is waterlogged with them – full of concern about changes in the climate?

Two studies appearing in the journal Nature Climate Change have made surfers stand up on their boards and reconsider the situation.

A study led by Dr Andrew Dowdy, a researcher at the Centre for Australian Weather and Climate Research (CAWCR) predicts that rising temperatures will in fact reduce the number of storms causing big waves by the end of the century on the central east coast of Australia.

Potentially destructive

The storms that do occur could be more intense and potentially destructive – but the consistency of wave patterns will be reduced.

That’s bad news for surfers of the future in that area – one of the world’s surfing hotspots. They’ll just have to move elsewhere. Dowdy told the Climate News Network that his projections only relate to that particular region, and they are not necessarily applicable to other coastal regions.

But another study, led by Mark Hemer, a senior research scientist at CAWCR, indicates that surfers might be having to ride smaller waves in future in other parts of the world as well.

Using ocean modelling techniques, Hemer and his colleagues predict a decrease in annual wave height over more than 25% of the global ocean area by the end of the century. The North Atlantic is likely to see a decrease in wave heights during all seasons, and waves are likely to be smaller in the winter months in the North Pacific and Indian Ocean.

But all is not lost. The study predicts that some regions − including  the waters off the south coast of Australia and New Zealand − will see bigger waves of between 5% and 10% above present size averages during winter months.

Surfers are worried about other climate change related threats to their activities. There are fears that rising sea levels could threaten key surfing areas.

Surfers regularly monitor water conditions – everything from acidity levels to rubbish content and sewage levels in the seas.

Surf zone

The Save the Waves Coalition − a US-based group that lobbies to protect the coastal environment, with a particular focus on what it calls the surf zone − monitors development activities in surfing areas worldwide.

Its “endangered waves” campaign lists projects that threaten key surfing areas – from plans to construct a nuclear power station on the coast of South Africa to a series of coal-fired power plants proposed for the coast of Chile.

And Climate change is seen as a major challenge facing the surfing industry.

“The unfortunate truth is that the threats to surfing habitat are now growing exponentially due to the impacts of man-made climate change,” says the California-based Sustainable Surf organisation. – Climate News Network

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Why Greenland is likely to melt more quickly

Why Greenland is likely to melt more quickly

Scientists who have examined the role of the bedrock on which the Greenland ice sheet rests think it shows the huge island is more vulnerable than realised to global warming.

LONDON, 1 October – Climate scientists have thought a little more deeply about the state of the Greenland ice sheet and their conclusions are ominous.

They think that the northern hemisphere’s largest assembly of ice and compacted snow is more vulnerable to climate change than anybody had previously thought.

Marion Bougamont of the Scott Polar Research Institute in Cambridge, UK, and colleagues report in Nature Communications that they factored in not just a mathematical model of the melting ice from Greenland, but also the role of the soft, yielding and absorbent mud and rock beneath.

The Greenland ice sheet is the planet’s second largest body of terrestrial ice. It covers 1.7 million square kilometres and if it were all to melt, the world’s sea levels would rise by more than seven metres.

Right now, about 200 gigatonnes of Greenland ice a year turn to water and run into the sea. This alone raises sea levels at the rate of 0.6 millimetres a year. In fact the increase in sea levels from all causes – glacier retreat worldwide, ice cap melting and ocean thermal expansion –  is now 3 mm a year.

Researchers have repeatedly found evidence of an acceleration of melting, in some cases by looking at what is happening within the ice or on the surface, or by taking a new look at satellite data.

Less stable

But the latest calculation goes even deeper: into the mud below the ice. According to the new model, and to evidence from surveys, melting will be complicated by the conditions deep under the ice.

The ice sheets are moving, naturally and at different speeds, causing the ice to shear or flow, and the assumption has always been that the ice is flowing over hard and impermeable rock. A closer look suggests a different process.

Lakes of summer meltwater tend to form on the ice sheet surface: if the ice below fractures, these lakes can drain in a matter of hours. The meltwater flows down within the ice, and into the sediment below it.

“The soft sediment gets weaker as it tries to soak up more water, making it less resistant, so that the ice above moves faster. The Greenland ice sheet is not nearly as stable as we think,” said Poul Christofferson, a co-author.

And Dr Bougamont said: “There are two sources of net ice loss: melting on the surface and increased flow of the ice itself, and there is a connection between these mechanisms that isn’t taken into account by standard ice sheet models.”

Rapid change

At present, the annual flow of ice meltwater is more or less stable. In warmer years, the ice sheet becomes more vulnerable because more meltwater gets to the muddy absorbent bedrock. Because there is a limit to how much the sediment below can hold, the ice sheet becomes more vulnerable during extreme events such as heat waves.

And, of course, if under such a scenario it is vulnerable, it continues to become more vulnerable as average temperatures rise and extreme events become more frequent, and more extreme. And a closer look at recent geological history shows just how fast change can happen.

In a separate study in Nature Communications, Katharine Grant of the Australian National University and colleagues report that they examined evidence of the melting process at the close of each of the last five ice ages.

They looked at data from wind-blown dust in sediment cores from the Red Sea, and matched these with records from Chinese stalagmites to confirm a picture of pronounced climate change at the end of each ice age, and calculated that sea levels rose at the rate of 5.5 metres per century.

These however were exceptional events, and there were more than 100 smaller sea level events in between the big five.

“Time periods with less than twice the modern global ice volume show almost no indications of sea level rise faster than about 2 metres per century,” said Dr Grant. “Those with close to the modern amount of ice on Earth show rates of up to one to 1.5 metres per century.” – Climate News Network

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Fresh water causes Antarctic seas to rise faster

Fresh water causes Antarctic seas to rise faster

Researchers in the UK have established that billions of tonnes of fresh water from melting glaciers are causing Antarctic sea levels to rise much higher and faster than the global average.

LONDON, 7 September, 2014 − Sea levels around Antarctica are rising faster than anywhere else in the southern ocean. The global average rise in ocean heights in the last 19 years has been 6cms, but the rise in seas around Antarctica is 2cms higher.

This seemingly counter-intuitive finding is certainly a consequence of melting ice in the Southern Ocean, but the connection with global warming is, for the moment, tenuous. The agency that is behind the rising sea levels is simply an excess of fresh water from melting glaciers − about 350 billion tonnes of it.

“Fresh water is less dense than salt water, and so in regions where an excess of fresh water has accumulated we expect a localised rise in sea level,” says Craig Rye, an oceanography researcher at of the University of Southampton in the UK, who, with colleagues, has published the findings in Nature Geoscience.

Partly because the oceans are warmer and are therefore expanding, and partly because the terrestrial glaciers are in retreat, global sea levels on average have crept up by about 3 millimetres a year. Waters off the Antarctic shelf seem to be gaining an additional 2mm a year.

Less saline

The scientists studied satellite scans of a region of more than a million square kilometres to make their finding, and used ship-based studies of the Antarctic sea water to confirm that is has become less saline.

The melting of the Antarctic ice sheet – German scientists recently calculated that around 125 cubic kilometres of meltwater is running off the continent each year − and the thinning of the floating ice shelves is enough to explain the unexpected rise.

Computer model studies confirm the interpretation that the rise is happening because the southern seas have just got fresher. The consequences in the longer term are uncertain.

Rye, a postgraduate researcher, said: “The interaction between air, sea and ice in these seas is central to the stability of the Antarctic ice sheet and global sea levels, as well as other environmental processes, such as the generation of Antarctic bottom water, which cools and ventilates much of the global ocean abyss.” – Climate News Network

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Doors open at Ban Ki-moon’s ‘Last Chance Saloon’

Doors open at Ban Ki-moon's 'Last Chance Saloon'

The UN secretary-general is attempting to prevent world leaders sleepwalking into disaster by asking them to make new pledges at a climate summit this month on cutting greenhouse gases.

LONDON, 3 September, 2014  It is widely acknowledged that the planet’s political leaders and its people are currently failing to take enough action to prevent catastrophic climate change.

Next year, at the United Nations climate change conference in Paris, representatives of all the world’s countries will be hoping to reach a new deal to cut greenhouse gases and prevent the planet overheating dangerously. So far, there are no signs that their leaders have the political will to do so.

To try to speed up the process, the UN secretary-general, Ban Ki-moon, has invited world leaders to UN headquarters in New York on 23 September for a grandly-named Climate Summit 2014.

He said at the last climate conference, in Warsaw last year, that he is deeply concerned about the lack of progress in signing up to new legally-binding targets to cut emissions.

If the summit is a success, then it means a new international deal to replace the Kyoto Protocol will be probable in late 2015 in Paris. But if world leaders will not accept new targets for cutting emissions, and timetables to achieve them, then many believe that political progress is impossible.

Danger threshold

Ban Ki-moon’s frustration about lack of progress is because politicians know the danger we are in, yet do nothing. World leaders have already agreed that there is no longer any serious scientific argument about the fact that the Earth is heating up and  if no action is taken  will exceed the 2°C danger threshold.

It is also clear, Ban Ki-moon says, that the technologies already exist for the world to turn its back on fossil fuels and cut emissions of greenhouse gases to a safe level.

What the major countries cannot agree on is how the burden of taking action should be shared among the world’s 196 nations.

Ban Ki-moon already has the backing of more than half the countries in the world for his plan. These are the most vulnerable to climate change, and most are already being seriously affected.

More than 100 countries are currently meeting in Apia, Samoa, at the third UN Conference on Small Island Developing States, which ends tomorrow. In their draft final statement, they note with “grave concern” that world leaders’ pledges on the mitigation of greenhouse gases will not save them from catastrophic sea level rise, droughts, and forced migration.

“We express profound alarm that emissions
of greenhouse gases continue to rise globally”

Many of them have long advocated a maximum temperature rise of 1.5°C to prevent disaster for the most vulnerable nations, such as the Marshall Islands and the Maldives.

The draft ministerial statement says: “Climate change is one of the greatest challenges of our time, and we express profound alarm that emissions of greenhouse gases continue to rise globally.

“We are deeply concerned that all countries, particularly developing countries, are vulnerable to the adverse impacts of climate change and are already experiencing an increase in such impacts, including persistent drought and extreme weather events, sea level rise, coastal erosion and ocean acidification, further threatening food security and efforts to eradicate poverty and achieve sustainable development.”

Devastating consequences

Speaking from Apia, Shirley Laban, the convenor of the Pacific Islands Climate Action Network, an NGO, said: “Unless we cut emissions now, and limit global warming to less than 1.5°C, Pacific communities will reap devastating consequences for generations to come. Because of pollution we are not responsible for, we are facing catastrophic threats to our way of life.”

She called on all leaders attending the UN Climate Summit in New York to “use this historic opportunity to inject momentum into the global climate negotiations, and work to secure an ambitious global agreement in 2015”.

This is a tall order for a one-day summit, but Ban Ki-moon is expecting a whole series of announcements by major nations of new targets to cut greenhouse gases, and timetables to reach them.

There are encouraging signs in that the two largest emitters – China and the US – have been in talks, and both agree that action is a must. Even the previously reluctant Republicans in America now accept that climate change is a danger.

It is not yet known how many heads of state will attend the summit in person, or how many will be prepared to make real pledges.

At the end of the summit, the secretary-general has said, he will sum up the proceedings. It will be a moment when many small island states and millions of people around the world will be hoping for better news.  Climate News Network

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