Antarctic ice is under attack from sea and air

Antarctic ice is under attack from sea and air

Satellite and radar studies show that twin forces causing the vast ice shelf to thin and become less stable could have a serious impact on global sea levels.

LONDON, 18 May, 2015 − Scientists have measured the rate of thinning of the great sea ice shelf of the Antarctic Peninsula and have identified the mechanisms at work above and below the shelf.

The collapse of floating sea ice makes no direct difference to global sea levels – but the effects could nevertheless lead to higher waters everywhere.

Paul Holland, of the British Antarctic Survey (BAS), and research colleagues from the US report in the journal The Cryosphere that they used satellite measurements and radar studies between 1998 and 2012 to confirm that the Larsen C ice shelf has lost four metres of ice, and is a metre lower at the surface.

Warmer waters

This is the largest of three shelves that have been under study for decades; the Larsen A and Larsen B shelves have already broken off and drifted north to warmer waters.

The Antarctic Peninsula is one of the fastest-warming regions of the world: 2.5°C in the last 50 years.

“What’s exciting about this study is we now know that two different processes are causing Larsen C to thin and become less stable,” says Dr Paul Holland, lead author of the BAS study.

“Air is being lost from the top layer of snow (called the firn), which is becoming more compacted, probably because of increased melting by a warmer atmosphere.

“We expect that sea-level rise around the world will be something in excess of 50 cm higher by 2100 than it is at present”

“We know also that Larsen C is losing ice, probably from warmer ocean currents or changing ice flow. If this vast ice shelf − which is over two and a half times the size of Wales, and 10 times bigger than Larsen B − was to collapse, it would allow the tributary glaciers behind it to flow faster into the sea. This would then contribute to sea-level rise.”

A collapse of the shelf could occur within a century. When the two companion Larsen glaciers broke away, the glaciers that flowed from the ice-capped continent towards the sea began to accelerate.

Offshore ice, held fast to the shoreline, is a factor that helps keep glacier flow at its proverbially glacial pace. Once it has gone, the frozen rivers of ice onshore naturally begin to flow faster.

“We expect that sea-level rise around the world will be something in excess of 50 cm higher by 2100 than it is at present, and that will cause problems for coastal and low-lying cities,” says David Vaughan, director of science at the BAS.

“Understanding and counting up these small contributions from Larsen C and all the glaciers around the world is very important if we are to project, with confidence, the rate of sea-level rise into the future.”

The study is a confirmation of earlier research in which other groups, using different approaches, have already identified shelf ice loss and have warned that Antarctic melting could accelerate. Satellite-based measurements have also linked glacial melting with an acceleration in sea level rise.

Precision measurement of sea level rise is not easy. Oceans rise and fall with the tides, the water isn’t level anyway, and salinity and temperature differences in the oceans, and gravitational anomalies in the ocean basins, all mean that the ocean surfaces naturally undulate.

And the continents don’t keep still. Land surfaces from which researchers base their measurements also slowly rise or fall.

Accelerated rise

Christopher Watson, senior lecturer in the School of Land and Earth at the University of Tasmania, Australia, and colleagues report in Nature Climate Change that a different approach to the problem suggests that – contrary to previous estimates – sea level rise has accelerated in the last decade.

He and his colleagues searched not just global positioning satellite evidence from the surface waters but also from the land for signs of “bias” in the data. They also used evidence from hourly tide gauges from around the world and recalculated the rate of change.

What they found was that, overall, sea level rise in the last two decades has been at a rate just under, rather than just over, 3mm a year.

But the overestimate for the first six years of the survey had been much higher, which in turn suggested that the rate of rise had actually accelerated during this century, in a way that is consistent with the rate of glacial melting − at least from the Greenland and West Antarctic ice caps. – Climate News Network

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Earth wins time as land and seas absorb more carbon

Earth wins time as land and seas absorb more carbon

Climate change has intensified more slowly than scientists had expected because the continents and oceans are absorbing more atmospheric carbon dioxide.

LONDON, 17 May, 2015 − Half of all the carbon emissions from burning fossil fuels remain in the atmosphere. The good news is that only half remain in the atmosphere, while the rest have been taken up by the living world and then absorbed into the land, and the ocean. That is, as carbon dioxide levels in the atmosphere have risen, so also has the planet’s capacity to soak up atmospheric carbon.

The implication is that what engineers call “positive feedback” – in which global warming triggers the release of yet more greenhouse gases into the atmosphere to accelerate yet further warming – doesn’t seem to be at work yet.

The implication, too, is that the world’s governments still have time to launch determined programmes to sharply reduce fossil fuel use, and switch to wind, solar and other renewable energy sources before climate change disrupts the planet’s food security and exacts what could be a devastating toll on the biosphere.

But most climate scientists know all this anyway: the real significance of a new study in the journal Biogeosciences is that US and British scientists have narrowed some of the uncertainties in what climate scientists like to call the carbon budget: how much gets into the atmosphere, where it goes, and how long it stays.

That is because although the big picture – that carbon dioxide levels in the atmosphere are beginning to rise steeply – has been confirmed repeatedly by systematic measurements since 1956, the potential margin of error has been considerable.

“This increased uptake by land and ocean is not only surprising; it’s good news”

“There is no question that land and oceans have, for at least the last five and half decades, been taking up about half of the carbon emitted each year. The outstanding question is, Why?” said Richard Houghton of the Woods Hole Research Center in Massachusetts, one of the authors.

“Most of the processes responsible for that uptake would be expected to slow down as the Earth warms, but we haven’t seen it yet. Since the emissions today are three times higher than they were in the 1960s, this increased uptake by land and ocean is not only surprising; it’s good news.

“Without it, the concentration of CO2 in the atmosphere would be twice what it is, and climate change would be much farther along. But there’s no guarantee that it will continue.”

The carbon budget is an integral part of the climate puzzle: all simulations of how climate will change with increasing emissions from fossil fuels depend on an understanding of how much carbon dioxide concentrates in the atmosphere and what happens to it after that.

In the last few months researchers have reported a dramatic uptake of atmospheric carbon by new forests and the growth of woodland on the world’s savannahs and pinpointed the fjords – those steep, still stretches of sea in mountainous coastlines in the high latitudes – as prime “sinks” for atmospheric carbon.

Uncertainties narrowed

At the same time others have once again confirmed fears that thawing permafrost could release vast quantities of carbon stored for millennia is semi-decayed and now frozen vegetation.

But these have been studies of small pieces of the big puzzle. What the Biogeosciences authors did was to refine two global uncertainties. One is how much fossil fuel is burned each year and the other is how much is stacking up in the atmosphere.

Both sound simple, but the first question is complicated by differences in the ways nations maintain their own energy inventories, and the way they report the details, and the second depends on how the use of land has changed, how the oceans are responding to higher levels of acidification and how carbon dioxide levels vary according to region, and to season.

With greater certainty in the answers to the second question – which began with one single set of measurements at the top of a mountain in Hawaii now replicated worldwide – researchers found they could make more sense of the first question, and narrow the uncertainties to a point where they could write that they were “93% confident that terrestrial C uptake has increased and 97% confident that ocean C uptake has increased in the last five decades.

“Thus it is clear that arguably one of the most vital ecosystem services currently provided by the biosphere is the continued removal of approximately half of atmospheric CO2 emissions from the atmosphere.” − Climate News Network

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Major attraction of fjords is as carbon ‘graveyards’

Major attraction of fjords is as carbon ‘graveyards’

The splendour of fjords is widely admired, but scientists say they are also carbon sinks that play an important role in regulating Earth’s climate.

LONDON, 12 May, 2015 − Fjords, those dramatic narrow inlets in mountainous coastlines, are more than just beauty spots. New research shows that they are also major repositories of organic carbon, and therefore a vital part of the planet’s climate system.

Although they cover only 0.1% of the surface area of the oceans, they serve as graveyards for 18 million tonnes of organic carbon annually − 11% of all the marine carbon buried globally each year.

Richard Smith, an organic geochemist at Global Aquatic Research in New York, and colleagues report in Nature Geoscience that they analysed 573 surface samples and 124 sediment cores from nearly every fjord system in the world. These include Norway, Sweden, Greenland, Scotland, Svalbard, Western Canada, Alaska, Chile, New Zealand and Antarctica.

Sediment accumulation

Organic carbon is – or once was – plant tissue fashioned by photosynthesis from atmospheric carbon dioxide. And fjords, which are narrow, deep estuaries formed at high latitudes during glacial periods, are sites of sediment accumulation, serving as traps for all the organic carbon that flows into them.

Great rivers with magnificent deltas and estuaries also bear huge quantities of organic carbon, but much of this gets back into carbon dioxide form and is released into the atmosphere before it gets to the open sea.

But fjords, protected from ocean disturbance, become repositories for vast quantities of eroded material and landslips washed down the steep mountain sides. Because the fjords are so deep, the organic carbon is buried in a way that prevents most of it from being recycled.

The calculation is that fjords may play an important role in moderating atmospheric carbon dioxide levels during the advance and retreat of glaciers.

When the glaciers advance, much of the buried carbon would be pushed out onto the continental shelf and start turning back into greenhouse gas, eventually to warm the planet and slow the glaciation process.

During a glacial retreat, such as the present, the inlets become stores of organic carbon, preventing temperatures from rising too fast.

Piece of the puzzle

To understand climate, scientists must first account for all the elements that drive the climate machine. The carbon cycle – the traffic of carbon between air and living things and rocks and water – is a vital part of this machine, and the scientists now have yet another piece of the puzzle in place.

“In essence, fjords appear to act as a major temporary storage site for organic carbon in between glacial periods,” says one of the report’s authors, Candida Savage, a marine ecologist at the University of Otago in New Zealand.

“This finding has important applications for improving our understanding of global carbon cycling and climate change.” – Climate News Network

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Seas generate rising tide of renewables ideas

Seas generate rising tide of renewables ideas

The EU says it is time for tides to provide energy for Europe from the Atlantic and end reliance on the burning of polluting fossil fuels.

LONDON, 11 May, 2015 − A race is on worldwide to harness the tides and waves for electrical power, with more than 100 different devices being tested by companies hoping to make a commercial breakthrough.

And a new report from the European Union’s Joint Research Centre expresses confidence that the Atlantic Ocean will soon be an important contributor to the continent’s energy mix.

It adds that many other countries with big tidal ranges and long coasts are also banking on this form of renewable energy to help reduce fossil fuel use.

For years, it has been predicted that the vast quantities of energy available in the oceans would be harnessed by human ingenuity to provide without the need for burning fossil fuels, but progress has been slower than expected.

Different techniques

While it has proved possible to generate  electricity with many different techniques, scaling these up into large-scale power stations to supply the electricity grid has not so far been economic.

The two most promising basic ideas are to use the currents and the build-up of water at each tide to drive turbines to make electricity, or to convert the power in wave motions to energy.

In Europe, the countries with Atlantic Ocean coastlines – such as the UK, Ireland, France, Spain, Portugal, Denmark, the Netherlands and Norway – are all developing technologies. And in 2014, the EU launched what it called its Blue Energy Action plan to finance and encourage development. The latest report details progress so far.

Most of the technologies are not new ideas, but the trick is turning a demonstration model into a viable power station.

The one exception is tidal energy in the form of a barrage across a river, which has been in use for years.

The best known is the 240 megawatt (MW) La Rance tidal barrage in France, operating successfully since 1966. Another 254 MW tidal plant has opened in Sihwa in South Korea, and other barrages producing at total 2,680 MW are planned worldwide − although  many  have proved controversial because of their  effects on fish and birds.

Tidal lagoons − reservoirs that stand in an estuary or close to the shore, and which fill and then empty with each tidal cycle − have  now won much more favour, and one is  being developed in Swansea Bay in south Wales.

The worldwide potential of this technology is estimated at 80 gigawatts (GW), or the equivalent of 80 large coal-fired power stations.

Already in successful operation at some sites, but yet to be scaled up to full commercial development, are underwater turbines − similar to wind turbines − that use the energy in tidal streams to make electricity.

In Europe, these devices will be viable in countries with high tides and strong tidal streams − particularly France, Ireland, Norway and the UK, but also  in some parts of Belgium, Italy and the Netherlands. These are believed to offer  the highest net potential contribution  to the European energy system, according to the report.

The first large-scale tidal array is being built in the Pentland Firth, off northern Scotland. It will provide power to 175,000 homes.

New connections

Like the deployment of wind farms, potential tidal power arrays are often in remote locations far from cities. The report points out that these technologies will require new grid connections and integration into the European grid to get most value from them.

A new generation of devices not placed on the sea bed, but either floating like kites on a string or operating from platforms, is under development. Their advantage is that they avoid the cost of being built on the sea bed, and can also  exploit the greater strength of the tides nearer the surface of the sea.

Some of the materials being used to build devices to withstand the power of the sea, and the methods that are being used, are being kept secret for commercial reasons, but they have some of the biggest companies in Europe as their backers.

The commercial advantage of tidal devices is that the tides are predictable years in advance

Another new generation of micro-turbines, owned by coastal communities and anchored offshore to take advantage of tidal flows, is under development. These could give communities isolated from the grid their own power source, like solar panels do in remote parts of Africa and Asia.

There are an estimated 100 companies developing tidal energy devices worldwide, half of them  in the EU, where many are supported by development grants. Four tidal energy stations are already in operation in Europe, and another 31 are expected to be completed by the end of 2016. Many more are in the planning stage.

The commercial advantage of tidal devices is that, unlike some other forms of renewable energy, the tides are predictable years in advance. Wave power, on the other hand, suffers because of its unpredictability and the need to make devices robust enough to stand up to the battering  they receive.

Potential supply

That has not stopped a large number of development projects being built, principally because the potential energy supply is vast –  30 times higher than tidal energy.

Some devices have already been operating successfully for 10 years, producing regular quantities of electricity, but they were built as demonstration models and not on a commercial scale.

Building structures large enough to produce a regular power supply at a cost that could be commercial has proved elusive, but the report describes a number of devices that are close to achieving commercial viability.

There are at least nine different technologies using wave power, and 170 wave energy developers worldwide.

The report also discusses technologies that use the different gradients of salinity in the sea to produce power, and the different water temperatures to generate energy.

However, it argues that both these ideas, while viable in theory, are further away from commercial operation in Europe than tidal stream or wave power. – Climate News Network

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Scientists weigh up new evidence on Antarctic ice melt

Scientists weigh up new evidence on Antarctic ice melt

Southern continent’s mysteries start to unfold as satellite data is used to measure the extent and pattern of increased ice loss that threatens to be a “runaway problem”.

LONDON, 7 May, 2015 − Antarctica has been losing its ice cover at an average rate of 92 billion tons a year since at least 2003, according to new research.

And while the scientists can’t yet say for certain that human-made climate change is the main cause, they warn that the ice loss has the potential to have serious impacts on sea level rise.

The southern continent is the Earth’s largest store of fresh water, but is also its least studied area, having had no known human visitors until the late 18th century. So while scientists have a clear idea of processes at work in the Arctic, the big picture at the other end of the planet has been uncertain.

Heavier snowfalls

West Antarctica has been losing vast chunks of ice, but greater average warmth has meant there have been heavier snowfalls, and the icepack in east Antarctica has been on the increase.

Now Christopher Harig and Frederik Simons, geoscientists at Princeton University in the US, report in the journal Earth and Planetary Science Letters that gravitational satellite data has delivered a method of “weighing” the ice sheet, and identifying a pattern of change.

Most of the loss has been from the West Antarctic region, where the glaciers are increasingly unstable. In 2008, the region was shedding ice at the rate of 121 billion tons a year. By 2014, this rate of loss had doubled.

At the same time, the ice sheet in East Antarctica had thickened – but  the gain made up for only about half the ice lost from the west.

Most scientists would be hard-pressed to find mechanisms that do not include human-made climate change”

In the period since 2003, ice loss over the whole continent increased at the rate of six billion tons a year. West Antarctica’s melting rate, however, accelerated by 18 billion tons a year during the same timespan.

So the researchers did the sums and arrived at an annual average loss of 92 billion tons a year. This could be envisaged as an iceberg the size of Manhattan Island in New York, and more than 1,600 metres high.

What the researchers cannot be sure of is the cause: is a natural cycle of climate at play, or is it a consequence of global warming because  of greenhouse gas emissions from the burning of fossil fuels?

“We have a solution that is very solid, very detailed and unambiguous,” Dr Simons says. “A decade of gravity analysis alone cannot force you to take a position on this ice loss being due to anthropogenic global warming. All we have done is take the balance of the ice on Antarctica and found that it is melting – there is no doubt.

Rapidly accelerating

“But with the rapidly accelerating rates at which the ice is melting, and in the light of other, well-publicised lines of evidence, most scientists would be hard-pressed to find mechanisms that do not include human-made climate change.”

The two scientists used data from a US-German research satellite called GRACE − short for Gravity Recovery and Climate Experiment.

The agency linked to the ice loss is a measured warming of the southern ocean that is reducing the sea ice, which in turn holds back the flow of ice on land. So glaciers are melting, and flowing towards the sea at a faster rate.

“The fact that West Antarctic ice melt is still accelerating is a big deal because it’s increasing its contribution to sea level rise,” Dr Harig says. “It really has the potential to be a runaway problem.

“It has come to the point that if we continue losing mass in those areas, the loss can generate a self-reinforcing feedback, whereby we will be losing more and more ice, ultimately raising sea levels.” – Climate News Network

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No green light for whitening Arctic’s melting ice

No green light for whitening Arctic’s melting ice

Scientists pour cold water on the idea of preventing ice melt by using geo-technology to keep it white so that it reflects sunlight and stays frozen.

LONDON, 4 May, 2015 – Yet another geo-engineering solution to climate change has been proven potentially useless: even if you could paint the Arctic white, the world would still get warmer.

For the second time in months, scientists at the Carnegie Institution for Science in the US have shown that some technological solutions won’t work even in principle, let alone in practice.

Geo-engineering is, for some, the simple technological answer to climate change: if humans have inadvertently warmed the planet’s climate through technological change, then surely they can cool it again intentionally through technological ingenuity.

But Carnegie global ecologist Ken Caldeira and research colleagues − having already demonstrated that piping cold deep waters to the ocean surface would accelerate global warming, rather than reduce it − now report in Environmental Research Letters that changing the reflectivity of the northern hemisphere won’t have the intended consequences either.

Climate machinery

Caldeira, Ivana Cvijanovic, now at the Lawrence Livermore National Laboratory, and Douglas MacMartin, of the California Institute of Technology, decided to consider an aspect of the climate machinery known as albedo. This is a measure of the planet’s reflectivity.

It works like this: dark colours, such as blue oceans and green rainforests, absorb more sunlight, while white and pale surfaces – snow caps and ice sheets, for instance  – reflect most sunlight.

So the Arctic and Antarctic keep cold simply by staying frozen. But any consistent thawing pattern will make an icy region warmer, at an increasing rate.

This is happening at measurable speed, in the northern hemisphere. “By the middle of the century, the Arctic Ocean is predicted to be ice-free during part of the year,” Dr Cvijanovic says. “This could create substantial ecological problems in the Arctic, including habitat range and loss of biodiversity.

“However, the problem is not only local. A number of studies have indicated that Arctic sea ice loss can affect weather patterns across the northern mid-latitudes, including Europe, most of North America and much of Asia.”

“Even if you could do it, the direct negative consequences of reducing the amount of sunlight available to marine ecosystems could be huge”

So it would make sense to keep the Arctic cold and white − perhaps by filling the ocean with floating reflective grains, or the air above it with tiny bubbles to bounce back the incoming sunlight.

But the Carnegie team decided to work out, with help from computer models, what a whiter Arctic would achieve in a world in which humans went on burning fossil fuels in ever-increasing quantities, in which the atmosphere eventually held four times the carbon dioxide levels recorded at the start of the Industrial Revolution, and in which average planetary temperatures went up by a devastating 10°C.

Cooling effect

The whitening of the Arctic would restore a percentage of the ice – about three-quarters of a square kilometre for every whitened square kilometre. But the cooling effect would be much more modest.

And the return of the ice would not preserve the permafrost – home to colossal quantities of organic carbon that could, if released, become carbon dioxide – or prevent escapes of another potent greenhouse gas, methane.

While it might work to keep a bay or inlet frozen, it would not, in principle, save a frozen ocean, or save the world from catastrophic climate change.

“Simply put, our results indicate that whitening the surface of the Arctic Ocean would not be an effective tool for offsetting the effects of climate change caused by atmospheric greenhouse gases,” Professor Caldeira says.

“Furthermore, it is not clear to me that there is a technologically feasible way of actually doing this. And even if you could do it, the direct negative consequences of reducing the amount of sunlight available to marine ecosystems could be huge.” – Climate News Network

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Global warming slowdown offers only fleeting relief

Global warming slowdown offers only fleeting relief

Scientists show that long-term temperature rise is the inevitable consequence of increasing greenhouse gas emissions from fossil fuels.

LONDON, 30 April, 2015 − The so-called hiatus in global warming will probably make no difference to the world in the long run, according to Australian scientists.

Using computer models to take the planetary temperature in 2100, they found that one set of models incorporated the slowdown, but others did not. In the end, the difference was barely significant: less than 0.1°C.

The hiatus is a measurable slowdown in the rate of increase in average global temperatures since the turn of the century.

But since, under the notorious business-as-usual scenario, average planetary temperatures in 2100 will be a predicted 5°C higher than at the start of the Industrial Revolution around 200 years ago, the conclusion is that the slowdown is fleeting.

Drastic steps

In the end, and unless the planet’s governments take concerted and drastic steps to reduce greenhouse gas emissions from fossil fuels, the outcome will be the same.

The study, the authors say in the journal Nature Climate Change, shows that the slowdown merely reflects short-term variability.

“Our research shows that while there may be short-term fluctuations in global average temperatures, long-term warming of the planet is an inevitable consequence of increasing greenhouse gas concentrations,” says Matthew England, chief investigator at the Centre of Excellence for Climate System Science at the University of New South Wales. “This much-hyped global warming slowdown is just a distraction from the matter in hand.”

It may be a distraction, but Professor England is one of an increasingly large set of researchers puzzling over the mechanisms that may be at work.

“This much-hyped global warming slowdown is just a distraction from the matter in hand”

There is – and climate scientists have confirmed this repeatedly over the last 100 years – a direct link between the planet’s temperature and the levels of carbon dioxide and other greenhouse gases in the atmosphere. In the last 30 years of the last century, planetary average temperatures rose steadily by the decade.

In the first 15 years of this century, the rise has been much smaller, even though the emissions have been greater.

Thirteen of the 14 hottest years ever recorded have fallen in this century, and 2014 was the hottest of them all, but that hasn’t stopped climate scientists from trying to account for the apparent slowdown − perhaps with an aspect of the climate machinery they have so far overlooked.

One group recently suggested that a natural cycle of cooling  in the Antarctic – a cycle much longer and slower than the sketchy data from the southern continent can confirm – has simply masked a continued rise in global temperatures.

Another has pointed to a relatively recent increase in volcanic eruptions that might have delivered enough sulphur aerosols into the atmosphere to block sunlight and to imperceptibly counter the warming trend.

Temporary storage

Braddock Linsley, research professor at the Lamont-Doherty Earth Observatory at Columbia University, New York, and colleagues proposed that the “missing” heat might be in temporary storage in the deep oceans.

And Professor England and colleagues proposed a link between the Pacific trade winds and a natural pattern of ocean circulation − a slow movement sometimes called the Pacific Decadal Oscillation (PDO) − that might be at work, overturning the ocean waters, cooling the surface and burying the warmth.

Now Dr Linsley and colleagues report in Geophysical Research Letters that the trade winds theory might provide at least part of the explanation.

They have been looking  at sea surface temperatures in the southern Pacific back to 1791, as witnessed by the growth of the coral reefs, and have identified a pattern of cyclic change with a period of perhaps about 25 years.

When the PDO goes into reverse, the so-called warming hiatus could end. If the present cycle began around 1999, then it could end quite soon − as early as 2020.

Dr Linsley told the Climate News Network: “There is already some evidence that the PDO may have started reversing late last year.” – Climate News Network

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Familiar fish find northern seas too warm for comfort

Familiar fish find northern seas too warm for comfort

Fish accustomed to shallow northern waters will search in vain for cooler depths as climate change warms the seas where they thrive.

LONDON, 18 April, 2015 – Some of Northern Europe’s favourite suppers may be about to swim off the menu altogether. Global warming could change the future catch, according to new research.

British scientists report in the journal Nature Climate Change that popular species such as haddock, lemon sole and plaice could become less common as the climate changes and the North Sea warms.

The North Sea is relatively shallow – during the height of the Ice Age, much of the sea bed was dry land – which means that fish that would otherwise find deeper waters to keep cool have nowhere to go.

The North Atlantic is warming fast. The mean annual North Sea surface temperatures have increased by 1.3°C in the past 30 years. This is four times faster than the global average. But fish evolved to make a living in the temperatures that suit them best, and the evidence is that the North Sea is increasingly host to species that were once characteristic of the Mediterranean.

Changing abundance

Fishing is big business: landings in 2007 in the region reached $1.2 billion, and accordingly the ecology of the North Sea has been intensively monitored. Cold-adapted landings have halved in the last 30 years, but landings of warm-adapted species have increased 2.5 times. With a baseline of very detailed data from the past, the researchers were able to use computer models to build up a picture of things to come in northern waters.

And the result is this: the demersal or bottom-feeding fish that were the basis of fish-and-chip suppers from Cornwall in the UK to northern Norway are likely to dwindle over the next 50 years. Many of them cannot move north to get away from the heat, because there is no suitable habitat, and they can’t go deeper, because there isn’t any depth. So the abundance of species will change with time.

“Our study suggests that we will see proportionately less of some of the species we eat most of as they struggle to cope with warming conditions in the North Sea,” said Louise Rutterford of Exeter University, the first author.

Squeezed out

“We provide new insight into how important local depths and associated habitats are to these commercial species. It’s something that is not always captured in existing models that predict future fish distributions.”

Other studies have found that fish in many regions are changing to new latitudes as climates change in response to greenhouse gas emissions from fossil fuel combustion. The same man-made global warming has brought a greater number of sardines, for instance, to northern waters, and in the US fishermen have had to sail ever further north to pursue the black bass. There has even been a warning that the retreat of the Arctic ice means that Atlantic halibut could actually migrate into the North Pacific.

So the latest message is confirmation of an increasingly familiar finding. “We will see a real changing of the guard in the next few decades,” said Steve Simpson, a marine biologist at Exeter, and another of the authors.

“Our models predict cold water species will be squeezed out with warmer water fish likely to take their place. For sustainable UK fisheries, we need to move from haddock and chips and look to southern Europe for our gastronomic inspiration.” – Climate News Network

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New ocean energy plan could worsen global warming

New ocean energy plan could worsen global warming

An apparently promising way of producing energy from the world’s oceans in fact risks causing catastrophic harm by warming the Earth far more than it can bear, US scientists say.

LONDON, 4 April, 2015 − One of renewable energy’s more outspoken enthusiasts has delivered bad news for the prospects of developing ocean thermal energy. His prediction is that although the technology could work for a while, after about 50 years it could actually exacerbate long-term global warning.

Of all the renewable energy technologies, ocean thermal energy conversion (OTEC) sounded like the perfect choice. This is a plan to exploit the difference between the warm surface and the cold deeps of the seas, and turn that difference into energy.

The agency that did the work would be a network of vertical pipes floating below the surface: it would not spoil the view from the coast, and it would deliver power day or night, whatever the weather. But there was more.

Enthusiasts pointed out that as a bonus, the pipes used in the energy conversion would bring a flow of nutrients from the cold, deep waters to the less-fertile but sunlit surface of the ocean, thus encouraging the growth of marine algae that would soak up more carbon from the atmosphere. And, as a bonus, the same process would accelerate the downward flow of carbon, where it could be sequestered on the sea bed.

Now one of renewable energy’s more vocal supporters has taken a closer look at the long-term consequences of the ocean pipes and come up with some discouraging news: an engineering programme intended to cool the planet would end up making it warmer. It would work for a while, he says, but after about half a century it would reduce the cloud cover and at the same time reduce the sea ice, to accelerate climate change once more.

Warming exacerbated

Ken Caldeira, senior scientist in the Department of Global Ecology at Stanford University’s Carnegie Institution, California, is one of the more energetic voices in climate research: he and his Carnegie colleagues have already warned that the world is feeling the heat from carbon dioxide released from car exhausts and factory chimneys and he has spoken up loudly for nuclear power, and indeed any “clean” energy sources.

He and Stanford colleagues Lester Kwiatkowski and Katharine Ricke report in Environmental Research Letters that when they began to simulate an ocean dotted with vertical pipes that exchanged deeper and shallower waters, they expected to confirm the value of such an approach. They could not.

“Our simulations indicate the likely sign and character of unintended atmospheric consequences of such ocean technologies,” they conclude, in formal science-speak. “Prolonged application of ocean pipe technologies, rather than avoiding global warming, could exacerbate long-term warming of the climate system.”

Research exercises such as this one cost nothing more than laboratory computing power and research time: their value once again is in reminding governments, campaigners and energy investors that the climate is an intricate piece of global machinery, and that there are no easy answers to the problems presented by renewable energy.

Radical change

They are also a reminder that geo-engineering of any kind to damp climate change could have unintended consequences. In this case – in an ideal, global simulation – it would change the thermal structure of the ocean altogether.

The Carnegie calculations work like this: cold air is denser than warm air. Water funnelled up the pipes on a very large scale from the depths would cool the air above the seas, and increase atmospheric pressure, which would reduce cloud formation over the seas. Since most of the planet is ocean, that means fewer clouds overall, which means more sunlight absorbed by the Earth rather than reflected back into space by the clouds.

And the same mixing of sea waters would bring sea ice into contact with warmer waters, which would mean less sea ice to reflect radiation, with the same result: accelerated global warming.

After 60 years, the simulated network of ocean pipes would cause an increase of global temperature by up to 1.2°C. After a few centuries, the same technology would take temperatures up by a catastrophic 8°5C.

“I cannot envisage any scenario in which a large scale global implementation of ocean pipes would be advisable,” said the report’s lead author, Dr Kwiatkowski. “In fact, our study shows it could exacerbate long-term warning and is therefore highly inadvisable at global scales.” – Climate News Network

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Climate-driven loss of habitat endangers marine mammals

Climate-driven loss of habitat endangers marine mammals

Global survey of threatened Arctic species warns that conservation won’t work without regulation of greenhouse gas emissions to halt climate change.

LONDON, 2 April, 2015 − Three kinds of whale, six varieties of seal, the walrus and the polar bear all have things in common: they are marine mammals, they depend on the Arctic for survival as species, they are vulnerable, and biologists know surprisingly little about them.

And since the Arctic is warming twice as fast as the rest of the planet, their future could become even more threatened as climate change increases habitat loss.

The stress, so far, is on the word “could”, as the first challenge is to establish the facts.

A global study team led by Kristin Laidre, principal scientist at the University of Washington Polar Science Centre in Seattle, reports in the journal Conservation Biology that marine mammals are “disproportionately threatened and data poor compared with their terrestrial counterparts”.

The narwhal, beluga and bowhead whales, the ringed, bearded, spotted, ribbon, harp and hooded seals, the walrus, and the polar bear are “particularly vulnerable due to their dependence on sea ice”.

Important predators

All these animals make their living on the ice and in waters north of the Arctic Circle, and all are important predators. They are also important to indigenous and settler peoples in the frozen North as many can be legally harvested, and others are iconic tourist attractions. Either way, they help communities survive.

“These species are not only icons of climate change, they are also indicators of ecosystem health, and key resources for humans,” Dr Laidre says. “Accurate scientific data – currently lacking for many species – will be key to making informed and efficient decisions about conservation challenges and trade-offs in the 21st century.”

So the researchers set out on what they believe is the first comprehensive global review of what is known about the populations of these animals, and about the way their local habitats may be changing.

“They need ice to find food, find mates, reproduce, and rear their young. It’s their platform of life.”

The study divided the Arctic into 12 regions and began to look at population numbers and trends, and the local pattern of seasonal change in the ice.

They identified 78 distinct populations of the 11 species, and began to assemble estimates of numbers. These range from millions for the ringed seals to a few hundred for the beluga whales of Ungava Bay in the Canadian Arctic.

In many cases, researchers had too little information even to make a guess about whether local populations of any species were stable, declining or increasing. In their table of the trends of the 11 species in the 78 populations, the word “unknown” occurs more than 60 times.

They also charted profound reductions in ice cover. The sea ice naturally advances each winter, and retreats each spring, but because of global warming driven by human emissions of greenhouse gases released by fossil fuel combustion, the pattern of advance and retreat has changed dramatically. By 2040, according to some projections, the Arctic could be more or less ice-free each summer.

Extended summer

But change is visible now. In most regions, the scientists found that the summer period was extended by between five and 10 weeks. In Russia’s Barents Sea, the summer ice period is now 20 weeks longer – five months – than it was 30 years ago.

This presents a threat to the polar bear, and to the seals on which they feed. “These animals require sea ice,” Dr Laidre says. “They need ice to find food, find mates, reproduce, and rear their young. It’s their platform of life. It is very clear those species are going to feel the effects the hardest.”

On the other hand, the whale species might benefit – at least for a while – from reduced ice cover. Open water could offer a wider feeding range and greater marine productivity, and therefore more food.

The scientists provide a set of general recommendations for biologists, local authorities, government agencies and international organisations concerned with conservation of Arctic marine mammals. They also have a message for the entire planet.

As Dr Laidre says: “We may introduce conservation measures or protected species legislation, but none of those things can really address the primary driver of Arctic climate change and habitat loss for these species. The only thing that can do that is regulation of greenhouse gases.” – Climate News Network

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