Ecuador’s plants head uphill to escape warmth

Ecuador's plants head uphill to escape warmth

In just two centuries many plant species have scrambled 500 metres up the Andes in search of cooler temperatures, Danish scientists say.

LONDON, 20 September, 2015 – In 1802, the great explorer Alexander von Humboldt went up a mountain in Ecuador, and made a note of every plant and its elevation as he climbed.

In 2012, Danish researchers retraced his footsteps. They found that, in response to global warming, the plants Humboldt recorded had moved more than 500 metres uphill.

When Humboldt, whose “physical tableau” became one of the oldest plant data sets in the world, climbed the 6,268-metre Chimborazo volcano the highest plant was at 4,600 m. Naia Morueta-Holme  of Aarhus University and colleagues report in the Proceedings of the National Academy of Sciences that they found that the vegetation had gone up in the world.

“Right up at 5,185 m, we found the last trace of vegetation, a defiant little plant belonging to the sunflower family and half-covered in snow – in full flower in spite of the cold conditions, the thin air and the harsh wind,” she said.

Wholesale change

The scientists found changes all the way up the mountain. Individual species have moved up 500 m in the last 210 years. Glaciers are in retreat, the snow cover is lighter, and the lower parts of the mountain are now cultivated.

Humboldt’s tableau provides an insight into potential response to climate change as a consequence of rising carbon dioxide levels in the atmosphere, driven by fossil fuel combustion by human society.

“Even though the plants have kept up on average until now, we see many individual species that are lagging behind, while others – especially common species that are good at spreading and living under many different conditions – are moving upslope.

“We can thus expect even more drastic changes in the vegetation in the future, and there are concerns about how the rare and specialised species will survive, particularly in the tropics, where most of them grow,” Dr Morueta-Holme, now at the University of California at Berkeley, said.

Airborne menace

And according to a new study in the Proceedings of the Royal Society B, in the far north the Arctic mosquitoes are hatching earlier and growing faster. Lauren Culler of Dartmouth College in the US and colleagues made computer models of mosquito populations as a consequence of climate change and predict that, as Arctic temperatures rise by 2°C, the probability of mosquito survival and emergence from the tundra snowmelt would increase by half.

Since Arctic mosquitoes have a reputation for being more than usually ferocious, this could be uncomfortable for the caribou and any other potential donors of a blood meal. And since mosquitoes are also pollinators of tundra plants, and prey for Arctic birds, the overall impact on Arctic ecology could be significant.

The scientists used laboratory studies and fieldwork in western Greenland to follow the changing life cycle of the mosquito: warmer spring temperatures caused the creatures to emerge two weeks early and their larval and pupal stages were shortened by 10% for every 1°C increase in temperature.

Diving beetles consumed more of the immature mosquitoes, but they were at risk for shorter periods, so overall their chance of survival was greater. At 2°C, the chance of survival increased 53%. And as the insects increased in abundance, and moved further north, Dr Culler predicted “negative consequences for the health and reproduction of caribou.” – Climate News Network

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Hi-tech analysis pinpoints Antarctic ice sheet dangers

Hi-tech analysis pinpoints Antarctic ice sheet dangers

Precision mapping of West Antarctica’s melting glaciers could help climate scientists to predict potentially calamitous effects on sea levels.

LONDON, 25 August, 2015 – Scientists have used high-resolution computing techniques to calculate the future of the West Antarctic ice sheet over the next two or three centuries.

The West Antarctic peninsula right now is about the fastest-warming place on Earth. And, in the worst case scenario, glaciers will retreat by hundreds of kilometres, and seas will rise everywhere.

An estimated 80,000 cubic kilometres of ice could flow into the sea by 2100, and by 2200 this could rise to 200,000 cubic kilometres. By the end of this century, sea levels could have risen by 20cms, and 50cms by 2200.

This is an extreme case, but the forecasts for West Antarctica’s glaciers have been consistently alarming. In the last two years, scientists have confirmed that the rates of melt and retreat have accelerated, and that, under the combined effects of warmer air and sea, this melting may be irreversible.

Vulnerable mass

Stephen Cornford, a researcher at the School of Geographical Sciences at the University of Bristol in the UK, and colleagues report in the European Geosciences Union journal The Cryosphere that their chief concern was to help climate science by fixing with greater precision the things that might happen to the most vulnerable mass of ice on the frozen continent.

The new study tests a range of climate predictions in greater detail than before, over a greater area, and a longer period of time. But the uncertainties remain. Will human-induced greenhouse gas levels continue to rise? How will the oceans respond? What will be the consequences for snowfall south of the Antarctic Circle?

“Other regions of West Antarctica could thin to a similar extent if the ocean warms sufficiently”

So the study looks at all the possibilities in more detail, and the pay-off could be more confident predictions of climate change as the circumstances begin to change.

Dr Cornford says: “We expect future change in the West Antarctic ice sheet to be dominated by thinning in the Amundsen Sea Embayment, just as it is today, until at least the 22nd century. But other regions of West Antarctica could thin to a similar extent if the ocean warms sufficiently.”

A computer-generated map of the projected glacial retreat in the Amundsen Sea Embayment by 2154. Image: S.Cornford et al/The Cryosphere

A computer-generated map of the projected glacial retreat in the Amundsen Sea Embayment by 2154.
Image: S.Cornford et al/The Cryosphere

Serious consequences

The worst-case predictions are disconcerting, and could have serious consequences for the hundreds of millions of people who live in cities and on productive land at or near sea level – for instance on the Nile Delta or in Bangladesh – or even below sea level, protected by sea walls, such as in the Netherlands.

But they remain just that: worst case predictions. The scientists were not concerned with establishing probabilities for any scenario, just with employing complex mathematical techniques to extend climate models.

The chief aim of the study has been to find ways of making sense of all possibilities − from no change to calamitous change − in the factors that govern glacier loss.

Co-author Dan Martin, a computational scientist at the Lawrence Berkeley National Laboratory in California, says: “Much like a higher-resolution digital camera transforms a blur into a flock of birds, higher resolution in a computer model often helps to capture details of the physics involved, which may be crucial to the broad picture.” – Climate News Network

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Central Asia’s glaciers may lose half their ice by mid-century

Central Asia’s glaciers may lose half their ice by mid-century

The speed at which the warming climate is melting glaciers in Central Asia may ruin the water supply of millions of people within 50 years.

LONDON, 22 August, 2015 – Glaciers in the largest mountain range in Central Asia, the Tien Shan, have lost over a quarter of their mass in the last 50 years, and nearly a fifth of their area.

An international team of researchers estimates that since the 1960s the glaciers have shrunk by almost 3,000 square kilometres, losing an average of 60 sq km of ice annually.

The Tien Shan reach almost 7,500 metres (24,500 feet) in height, and are a vital reservoir for the countries through which they pass – China, Kazakhstan, Kyrgyzstan and Uzbekistan.

The team, from the GFZ German Research Centre for Geosciences and France’s National Centre for Scientific Research (CNRS), report in the current online issue of Nature Geoscience that about half of the mountains’ glacier volume could be depleted by the 2050s.

The researchers say the Tien Shan (which in Chinese means “the celestial mountains”) have lost 27% of their mass and 18% of their area since 1960.

Glaciers worldwide are melting at unprecedented rates, which is serious because they are often irreplaceable sources of drinking water, hydropower and irrigation. The Tien Shan are no different.

Long-term storage

The mountains form a vital part of Central Asia’s water cycle. Snow and glacier melt from the Tien Shan is essential for the water supply of the four countries they traverse.

“Despite this importance, only a little was known about how glaciers in this region changed over the last century,” says the principal investigator, Daniel Farinotti. Most of the direct monitoring programmes, which were closed with the end of the Soviet Union, have been resumed only recently.

Farinotti, from GFZ, and his colleagues have completed a reconstruction of the glaciers’ evolution in the Tien Shan. “We combined various methods based on satellite gravimetry, laser altimetry and glaciological modelling”, he says.

This let them plot the evolution of every single glacier. They came up with some surprising findings: currently, the range is losing ice at a pace that equals roughly double the annual water consumption of the whole of Germany.

Glaciers can store water as ice for decades, transferring winter snow and rainfall to the summer months by releasing it as meltwater. This is particularly important in seasonally arid regions which have months with virtually no precipitation. Their local water supply depends on meltwater availability, as Central Asia knows from experience.

Increased temperature contributes to both increased melt and reduced glacier nourishment”

Many people in Central Asia depend on water seasonally impounded by the glaciers of the Tien Shan, not only for water itself but for hydro-electricity and for food.

The pace of glacier retreat in the Tien Shan accelerated noticeably in the decade from the 1970s. Daniel Farinotti says: “The long-term signal is clearly related to the overall rise in temperature”. The study shows that the rise in temperature, and summer temperature in particular, is a primary influence on the region’s glaciers.

“Since the winter months in Central Asia are very dry and the mountains are that high, glaciers receive most of their snowfall during the summer”, Farinotti explains. “This means that an increased temperature contributes to both increased melt and reduced glacier nourishment – and obviously, both contribute to glacier wastage.”

Using the latest climate projections, which expect an additional 2°C of warming in summer temperatures between 2021 and 2050, the authors suggest what the mountains’ future evolution may look like. Half of the total glacier ice volume of the Tien Shan today could be lost by the 2050s, they believe. – Climate News Network

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Global glacier melt reaches record levels

Global glacier melt reaches record levels

Scientists say tens of thousands of glaciers are melting faster than ever − and many will continue to do so even if climate change can be stabilised.

LONDON, 5 August, 2015 – The world’s glaciers are melting fast − probably faster than at any time in recorded history, according to new research.

Measurements show several hundred glaciers are losing between half and one metre of thickness every year − at least twice the average loss for the 20th century − and remote monitoring shows this rate of melting is far more widespread.

The World Glacier Monitoring Service (WGMS), based at the University of Zurich, Switzerland, has compiled worldwide data on glacier changes for more than 120 years.

Drawing on reports from its observers in more than 30 countries, it has published in the Journal of Glaciology a comprehensive analysis of global glacier changes.

Pictorial sources

The study compares observations of the first decade of this century with all available earlier data from field, airborne and satellite observations, and with reconstructions from pictorial and written sources.

Dr Michael Zemp, director of WGMS and lead author of the study, says the current annual loss of 0.5-1 metre of ice thickness observed on “a few hundred glaciers” through direct measurement is two to three times more than the average for the last century.

Evidence of how much the Rhone glacier in the Swiss Alps receded between 2007 (above) and 2014. Images: Simon Oberli

Evidence of how much the Rhone glacier in the Swiss Alps receded between 2007 (above) and 2014. Images: Simon Oberli


“However, these results are qualitatively confirmed from field and satellite-based observations for tens of thousands of glaciers around the world,” he adds.

The WGMS compiles the results of worldwide glacier observations in annual calls-for-data. The current database contains more than 5,000 measurements of glacier volume and mass changes since 1850, and more than 42,000 front variations from observations and reconstructions stretching back to the 16th century.

Intense ice loss of the last two decades has resulted in a strong imbalance of glaciers
in many regions of the world

Glaciers provide drinking water for millions of people, as well as irrigating crops and providing hydropower. When they melt, they also make a measurable contribution to sea level rise.

The researchers say the current rate of glacier melt is without precedent at the global scale − at least for the time period observed, and probably also for recorded history, as reconstructions from written and illustrated documents attest.

Long-term retreat

The study also shows that the long-term retreat of glacier tongues is a global phenomenon. Intermittent re-advance periods at regional and decadal scales are normally restricted to a smaller sample of glaciers and have not come close to achieving the Little Ice Age maximum positions reached between the 16th and 19th centuries.

Glacier tongues in Norway, for example, have retreated by some kilometres from their maximum extents in the 19th century. The intermittent re-advances of the 1990s were restricted to glaciers in coastal areas, and to a few hundred metres.

The study shows that the intense ice loss of the last two decades has resulted in what it calls “a strong imbalance of glaciers in many regions of the world”. And Dr Zemp warns: “These glaciers will suffer further ice loss, even if climate remains stable.”

He told Climate News Network: “Due to the strong ice loss over the past few decades, many glaciers are too big under current climatic conditions. They simply have not had enough time to react to the climatic changes of the past.

“So they will have to retreat further until they are in balance with climatic conditions again. In the European Alps, many glaciers would lose about 50% of their present surface area without further climate change.” – Climate News Network

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Arctic’s melting ice shrinks shipping routes

Arctic’s melting ice shrinks shipping routes

The opening up of waters north of Siberia as Arctic ice melts will change world trade patterns by cutting a third off distances between north-west Europe and the Far East.

LONDON, 4 August, 2015 – The disappearing Arctic ice cap will boost trade between north-west Europe and countries such as China, Japan and South Korea by making the sea routes far shorter, according to economic analysts.

The new sea route will alter world trade, making northern countries richer, but causing serious problems for Egypt, which will lose a large chunk of revenue currently gained from ships coming through the Suez Canal.

One advantage to the environment − according to a discussion paper from the Netherlands Bureau for Economic Policy Analysis − is that ships will burn far less fossil fuel to reach their destination.

However, this gain will be offset when the volume of trade increases because of the shorter sea route, making climate change slightly worse.

Open all year

The northern sea route is already open in the summer months, but the paper predicts that it will be available all year round by 2030, or possibly sooner. It says that Arctic ice is melting faster than predicted by scientists.

To police the new route, the Russian government has already formed a federal state institution and is building 10 “relief ports” along the Siberian coastline for ships that might need repairs or supplies. China has signed a free trade agreement with Iceland in anticipation of regularly using the route.

The paper estimates that trade between north-west Europe and China, Japan and Korea will increase by 10% as a result of the opening of the route, but that this will happen gradually.

The northern route will become one of the busiest shipping lanes in the world, increasing the economic and political importance of the Arctic

Since 90% of world trade by volume is carried by ship, the distance between ports is a vital consideration. The northern route reduces the distance from Japan to north European countries by 37%, from South Korea by 31%, China 23%, and Taiwan 17%.

The advantage of shorter distances applies only to countries in northern East Asia. For countries south of the equator, such as Singapore and Indonesia, the southern route via Suez is still shorter.

Similarly, southern European countries do not gain because they remain roughly the same distance away from their trading partners whichever route they use.

The countries in Europe that will gain most from the new sea route are those with access to ports on the North Sea and the Baltic. These include Austria, Belgium, the Czech Republic, Denmark, Estonia, Finland, Germany, Ireland, Latvia, the Netherlands, Poland, Slovakia, Sweden, the UK and Norway.

Drop in trade

Some countries in eastern and southern Europe would experience a drop in trade because of the comparatively longer distances their exports and imports would need to travel, according to the report. These include Bulgaria, Croatia, Hungary, Italy, Romania and Slovenia.

The report says that roughly 8% of world trade goes through the Suez Canal, and that two-thirds of this volume will go via the shorter Arctic route. The northern route will become one of the busiest shipping lanes in the world, increasing the economic and political importance of the Arctic.

At the same time, it will put huge economic pressure on Egypt and Singapore, who rely heavily on shipping using the southern route.

Over time, the opening of the Arctic route will have knock-on effects on jobs and prosperity in all the countries concerned, but it is predicted that this will be a gradual rather than sudden process. – Climate News Network

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Half of climate safety level has gone

Half of climate safety level has gone

Global temperatures have risen by 1°C in the past 150 years, and one scientist says doubling that level could unleash catastrophic sea level rise this century.

LONDON, 2 August, 2015 – The world is now halfway towards the internationally-agreed safety limit of a maximum 2°C rise in global average temperatures, researchers say.

That limit seeks to prevent the global warming caused by the burning of fossil fuels exceeding 2°C above the pre-industrial global temperature. The UN’s Paris climate summit later this year aims to ensure that it is not breached.

It appears that the human race has taken roughly 250 years to stoke global warming by 1°C. On present trends, we look likely to add the next 1°C far more quickly – across much of the world, many climate scientists believe, by the middle of this century.

The research is published in the journal New Scientist, which commissioned it. As so often with climate projections, it needs qualifying and teasing apart.

Some scientists, for example, warn that there’s uncertainty about just what the pre-industrial global temperature was. The New Scientist research is careful to be specific: it says global surface temperature is now passing 1°C of warming relative to the second half of the 19th century.

Farewell, hiatus

And one of the four main trackers of temperature thinks that milestone will be passed only if there is a strong El Niño, the cyclic Pacific weather phenomenon that periodically brings widespread chaos in its wake.

However, the research looks likely finally to lay to rest the argument that global warming is slowing and stuttering to a virtual halt, the so-called hiatus theory. Kevin Trenberth, of the US National Center for Atmospheric Research in Boulder, Colorado, told New Scientist: There’s a good chance the hiatus is over.”

The hottest year since records began was by a very small margin – 2014, and this year’s El Niño could mean a temperature rise of 0.1°C this year, an increase which usually takes about a decade to develop. Dr Trenberth thinks 2015 is likely also to be a record-breaker. 

Between 1984 and 1998 the Earth warmed at 0.26°C a decade, but the Intergovernmental Panel on Climate Change (IPCC)  says the rate then fell back until 2012 to about 0.04°C, for a number of reasons, including a less active Sun, more cooling aerosols from volcanoes and Asian factories, and more heat being absorbed by the oceans. The New Scientist findings suggest that warming may soon revert to the higher rate. 

From a quite different source comes a warning not only that temperatures may soon start a marked rise, but that sea level may also accelerate far faster than most scientists think likely.

It is not difficult to imagine that conflicts arising from forced migrations and economic collapse might make the planet ungovernable”

The prospect it holds out is at odds with most mainstream climate science, and might well be discounted as alarmist and fanciful. But the lead author of the discussion paper in which it appears is the highly respected James Hansen, former director of NASA’s Goddard Institute for Space Studies.

He and his colleagues say the ice melting around Greenland and Antarctica will cause sea level rises much faster than mainstream predictions suggest, by several metres this century. This will add to a process which they say has already begun, accelerating the melting of the undersides of Antarctic glaciers and ice shelves.

Another consequence, they think, will be the shutting down of ocean currents which carry heat from the tropics to the polar regions, leaving the tropics to warm fast and the high latitudes to cool. This temperature difference, they say, will spawn superstorms unlike any seen so far.

All this, Professor Hansen and his colleagues say, could happen with a 2°C temperature rise, with devastating consequences: It is not difficult to imagine that conflicts arising from forced migrations and economic collapse might make the planet ungovernable, threatening the fabric of civilisation.”

Professor Hansen may of course be wrong, but it would be short-sighted to assume that he is. He has a strong record of ultimately being proved right. Climate News Network

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Melting sea ice means shortage of bear necessities

Melting sea ice means shortage of bear necessities

Researchers explode theory that polar bears can use hibernation techniques to last without food as climate change reduces their summertime hunting habitat.

LONDON, 20 July, 2015 – Global warming is likely to leave the polar bear high and dry and very hungry as increasing loss of sea ice reduces the hunting grounds of the Arctic’s top predator.

Researchers have established that while Ursus maritimus can survive for months without eating during winter hibernation, in the summertime it is not much better at going without food than any other mammal.

The polar bear is capable of shutting its own metabolism down to astonishingly low levels during hibernation and, until now, zoologists have surmised that the bear could minimise energy losses by entering a hibernation-like state when deprived of food.

But John Whiteman, a doctoral student in ecology, zoology and physiology at the University of Wyoming, and colleagues report in Science journal that that theory is wrong. Once they are up and hunting, bears need food.

Energy expenditure

“We report gradual, moderate declines in activity and body temperature of both shore and ice bears in summer, resembling energy expenditures typical of fasting, non-hibernating mammals,” they write.

As carbon dioxide levels in the atmosphere creep up, as a consequence of the human combustion of fossil fuels, so Arctic temperatures have on average risen.

The loss of sea ice in the Arctic has, over the last decade, happened even faster than climate scientists predicted, which creates problems for bears that need to hunt and gorge on high-calorie diets in preparation for the winter.

The polar bear hunts on the ice, and its preferred diet is the blubber-rich flesh of seals and small whales. On shore, it must forage for scraps, berries and small mammals while waiting for the seas to freeze again.

“Polar bears appear unable to meaningfully prolong their reliance on stored energy”

But Arctic summers have stayed milder for longer, and the areas of summer sea ice have steadily dwindled. So the bears have spent increasing periods without their preferred diet.

The orthodoxy had been that bears, while waiting for the first freeze, had been able to enter a state called “walking hibernation”. Whiteman and his fellow researchers took a closer look.

With help from government agencies, a US coastguard icebreaker, helicopter pilots and a large number of other people, they captured two dozen polar bears, fitted satellite collars, and implanted little devices that recorded body temperature and tracked their movements on shore and on ice in the Beaufort Sea, north of Alaska and Canada, between 2008 and 2010.

Core temperature

They found that the bears could do something physiologically clever to keep warm while swimming – they could temporarily cool their outermost skin layers to insulate their inner selves and keep their core body temperatures at a healthy level, and one bear was reported to have survived a nine-day swim from shore to ice.

But they also found that the bears were not much better than other mammals at walking around on dry land, looking for food that wasn’t there.

“We found that polar bears appear unable to meaningfully prolong their reliance on stored energy, confirming their vulnerability to lost hunting opportunities on the sea ice − even as they surprised us by also exhibiting an unusual ability to minimise heat loss while swimming in Arctic waters,” Whiteman says.

The evidence, however, suggested that “walking hibernation” didn’t actually exist. The researchers conclude that the bears “are unlikely to avoid deleterious loss in body condition, and ultimately survival, that are expected with continuous ice loss and lengthening of the ice-melt period”. – Climate News Network

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Too few specialists to track loss of Himalayan glaciers

Too few specialists to track loss of Himalayan glaciers

Millions of people rely on meltwater from the Himalayas, but lack of expertise and manpower is hampering the study of climate change impacts.

DELHI, 11 July, 2015 − Studying ice loss in the vast, inhospitable region of the Himalayas can be a very tricky business as most glaciers are found above 12,000 feet.

While much of the data is derived from satellite surveys, reliable field data is also vital − but skill shortages mean that only four of the approximately 9,500 glaciers spread across the Indian section of the Himalayas are being studied in detail.

Gathering field data involves a combination of skills that include high-altitude mountaineering. Weather restricts such work to about four months of the year, and there is also the constant danger of avalanches.

The mighty Gangotri glacier, in the far northwest of the country, is one of the four glaciers monitored in detail by field researchers.

Rapidly disintegrating

Recent studies indicate that the Gangotri, one of the Himalayas’ largest glaciers and a primary source of the Ganges, is rapidly disintegrating. Nearly 30 kilometres long and between 0.5 and 2.5km wide, it is at present retreating by between 12 and 13 metres a year.

To analyse the impacts of climate change, and to predict what will happen in the future in glacial regions, it is necessary to carry out what glaciologists refer to as surveys of mass balance – analysing the relative difference between the accumulation and melting of ice and snow on a glacier over a given period.

Collecting and interpreting data – from satellite imagery and from field surveys – is highly specialised. And Indian institutions say a big knowledge gap has developed, with only limited field data being collected and a lack of trained personnel available to interpret the results of remote sensing and other data.

A determined effort is now being made by several institutions to produce more trained glaciologists.

“There is evidence of changing climatic patterns leading to changing water flow patterns that
could have serious impacts”

The Indian government’s Department of Science and Technology is undertaking a project with the Swiss Agency for Development and Co-operation to train young scientists in glaciology as part of a Himalayan climate change and adaptation programme.

The Indian Space Research Organisation, which has been collecting satellite data on glaciers for many years, has a fully-fledged climate change department that is becoming more involved in monitoring glacier size and mass balance data.

The Divecha Centre for Climate Change, part of the prestigious Indian Institute of Science, is also combining studies of glaciology and climate change.

The generally accepted view is that the majority of glaciers in the Himalayas – an area often referred to as “The Third Pole”, due to its vast ice mass – are in retreat.

Reliable conclusions

Yet in some areas, such as the Karakoram Range in the west of the Himalayas, satellite data indicates that glaciers are advancing.

The International Centre for Integrated Mountain Development (ICIMOD), a regional organisation based in Nepal and specialising in the Himalayas/Hindu Kush region, says much more field work is needed to draw reliable conclusions about the extent of glacial loss across the Himalayas.

It points to data collected in Nepal and to studies in China that clearly show a decrease in glacial area. At the same time, fragmentation means that more smaller glaciers are being created.

The world should be concerned about glacial melt in the Himalayas, ICIMOD says, because “there is evidence of changing climatic patterns leading to changing water flow patterns that could have serious impacts”. − Climate News Network

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Climate change may knock seafood off the menu

Climate change may knock seafood off the menu

Researchers warn of a serious threat to fish, mussels and other marine species as carbon dioxide acidifies the world’s waters and increases temperatures.

LONDON, 7 July, 2015 – Pink salmon – the smallest and most abundant of the Pacific salmon species, and a supper table mainstay in many parts of the world – may be swimming towards trouble.

And they are not the only dish likely to disappear from the menu. Mussels, oysters, clam and scallop could all become scarcer and more expensive as the seas become more acid. And as the world’s waters warm, fish will start to migrate away from their normal grounds at an ever-increasing rate.

New research shows that as the world’s waters acidify because of carbon dioxide levels in the atmosphere, the pink salmon (Oncorhynchus gorbuscha) could become smaller and less likely to survive.

Potentially problematic

Previous studies have repeatedly and consistently explored potentially problematic consequences of change in the pH value of the world’s oceans. The higher the carbon dioxide concentrations in the air as a consequence of the burning of fossil fuels, the greater the change in oceanic acidity levels.

But researchers at the University of British Columbia, Vancouver, and colleagues looked at the special problems of freshwater fish.

Only about 0.8% of the world’s water is fresh – that is, found in lakes and rivers – but freshwater species represent 40% of all fishes. Salmon spawn and the young are reared in fresh water, before taking to the seas to mature, then returning to repeat the cycle.

The Vancouver scientists report in Nature Climate Change that they tested very young embryos in water at acidity levels expected at the end of this century, and observed them for 10 weeks.

They found that these laboratory-reared salmon were smaller, and their ability to smell was reduced, which could mean problems in returning to their spawning grounds or for scenting danger and responding to it.

“It is not too late for society to benefit greatly from immediate reductions in CO2 emissions”

At the age of seaward migration, they were less able to use oxygen in their muscles, which promised problems finding food, evading predators or making long journeys.

“The increase in carbon dioxide in water is actually quite small from a chemistry perspective, so we didn’t expect to see so many effects,” said Michelle Ou, lead author of the study. “The growth, physiology and behaviour of these developing pink salmon are very much influenced by these small changes.”

Salmon aren’t the only freshwater fish at risk from climate change. Research published in the journal Environmental Toxicology and Chemistry reveals that a rise in water temperatures of 5°C could make common pesticides and industrial contaminants ever more toxic.

Ronald Patra, an environmental scientist at the Department of Planning and Environment in New South Wales, Australia, and colleagues tested rainbow trout, silver perch, rainbowfish and western carp gudgeon at temperatures higher than optimum for the species and in the presence of endosulfan, chlorpyrifos and phenol − all of which wash into waterways from the land.

Results varied according to pollutant, species and temperature, but, overall, all three chemicals became increasingly toxic as water temperatures rose.

Future toxicity

On the coast of Mangalore in southwest India, where mussel farming has become a growing industry, researchers decided to test future toxicity conditions for the green mussel.

The Society of Experimental Biology meeting in Prague learned that the bivalves were raised in high temperature and low salt conditions and exposed to toxic algae and bacteria of the kind that might be expected in a changing climate, which in turn affected the timing of the monsoon in ways that could lower seawater salinity.

“This is likely to increase the chance of outbreaks of toxic plankton blooms and make farming bivalves such as mussels increasingly challenging,” the meeting was told.

But changes to water chemistry – once again, the shift in pH values as yet more carbonic acid builds up in the seas – create problems enough for the commercial shellfisheries.

Wiley Evans, research associate at the Ocean Acidification Research Centre of the University of Alaska Fairbanks, and colleagues report in the Public Library of Science journal PLOS One that shellfish farmers off the Alaska coast might, at extra expense, have to start modifying the sea water in their hatcheries because, the researchers reported, they expect “significant effects” from acidification by 2040.

The scientists monitored for 10 months the effects of water chemistry changes on oyster, clam, scallop and other shellfish larvae.

Alaska – with a limited growing season, melting glaciers that affect salinity, and with colder waters that more readily dissolve carbon dioxide – is a special case.

But in general, as researchers have repeatedly found, increasingly corrosive waters would make it more difficult for shellfish to exploit the calcium carbonate minerals needed to make shells.

Shellfish spend their maturity in one spot, whereas fish can and do shift their grounds when the conditions become uncomfortable − with consequences for established commercial catches such as sardines and sea bass.

Likely to migrate

But a 5°C average warming in global atmospheric temperatures – and climate scientists have repeatedly warned that this is possible before 2100 – means that fish are likely to migrate away from their existing habitats considerably faster than they are doing now.

Jean-Pierre Gattuso, of the Oceanological Observatory in Villefranche, France, and colleagues looked at the evidence on a global scale and report in Science journal that, without attempts to mitigate global warming, the oceans and the creatures in them will be seriously affected by temperature changes and acidification.

This is very bad news for the millions of people in the communities that depend on the seas for a living.

“On a positive note, we still have options to substantially reduce these impacts now, but the longer we wait the fewer and fewer options we have,” warns co-author William Cheung, of the fisheries centre at Canada’s University of British Columbia.

Commenting on the research, Jason Hall-Spencer, a professor of marine biology at Plymouth University in the UK, said: “This review screams at me that the evidence is in, and it is not too late for society to benefit greatly from immediate reductions in CO2 emissions.” – Climate News Network

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Global warming threatens colder climate for Europe

Global warming threatens colder climate for Europe

New evidence that increased melting of sea ice as the Earth warms could weaken the Gulf Stream and reduce temperatures in western Europe.

LONDON, 3 July, 2015 – Scientists have yet again warned that weakening ocean circulation in the North Atlantic could deliver a climate paradox − a colder Europe as a consequence of global warming.

A study published in Nature Climate Change found that as sea ice off Iceland and Greenland retreats, the flow of cold, dense water to the bottom of the North Atlantic ocean could be reduced, and therefore weaken the warming effects of the Gulf Stream.

The great submarine current − sometimes called the Atlantic Conveyor − flows south to surface in the tropics as the Gulf Stream, which then flows north again to deliver tropic warmth to European coasts.

However, a slowdown in the natural overturning of the ocean could weaken the Gulf Stream, which in turn could cool the atmosphere over the British Isles and western Europe.

“A warm western Europe requires a cold North Atlantic, and the warming that the North Atlantic is now experiencing has the potential to result in a cooling over Western Europe,” says Kent Moore, a professor of physics at the University of Toronto Mississauga, Canada.

Calamitous change

Such a possible collapse of a natural oceanic system is predicated as one of the irreversible tipping points that could result in calamitous climate change.

Scientists have twice warned in the past six months that such change could be irreversible, unless governments jointly decide to dramatically reduce greenhouse gas emissions from the combustion of fossil fuels by switching to renewable sources of energy.

Another research group reported in March this year on how the changing salinity of the northern ocean waters − because of the increasing flow of meltwater from land-borne glaciers − threatened a weakening of the Atlantic Conveyor.

“The heat exchange is weaker – it’s like turning down the stove 20%”

In the latest study, Professor Moore and colleagues from Norway, the US and the UK looked not at changes in ocean salinity, but at the exchange of heat between sea and air.

Climate is driven by contrasts, and the flow of heat between water and wind in winter has weakened by around 20% since 1979. The Arctic is the fastest-warming region of the planet, and changes in the polar climate can have dramatic consequences for the temperate zones.

Prof Moore and his colleagues looked at wintertime data from the Iceland and Greenland Seas between 1958 and 2014, then used computer simulations to model potential changes to the Conveyor − more formally known to oceanographers and climate scientists as the Atlantic Meridional Ocean Circulation.

Cold and salty

The warm current loses its heat to the atmosphere as it moves north, and water that is both cold and salty is denser and more likely to descend.

The most effective place for such a process to happen is at the edge of the sea ice. If the sea ice retreats, then so does the region of maximum heat exchange. For the past 10,000 years or so, this heat exchange has happened at the ideal spot for surface waters to sink. Any change might not be for the better.

The Gulf Stream is the agency that makes Britain, for example, about 5°C warmer than Labrador in Canada, on the same latitude. A British government chief scientific adviser once calculated that the Gulf Stream delivered the warmth of 27,000 power stations. So if it weakens, Europe could start to feel the chill.

“The heat exchange is weaker – it’s like turning down the stove 20%,” Prof Moore says. “We believe the weakening will continue and eventually cause changes in the Atlantic Meridional Overturning Circulation and the Gulf Stream, which can impact the climate of Europe.” – Climate News Network

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