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UK seabirds sound climate warning

March 28, 2014 in Climate, Marine ecology, Ocean Warming, USA, Warming

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A Scottsh kittiwake: Numbers have plunged since 2000, with climate change thought to be reducing their main food source Image: By DickDaniels (http://carolinabirds.org)via Wikimedia Commons

A Scottsh kittiwake: Numbers have plunged since 2000, with climate change thought to be reducing their main food source
Image: By DickDaniels (http://carolinabirds.org)via Wikimedia Commons

By Alex Kirby

Once-familiar Scottish seabirds are among species whose numbers in the UK are falling sharply, scientists say – and the suspicion is that climate change is to blame.

LONDON, 28 March – Several familiar British birds are now showing drastic declines in numbers as the reality of climate change strikes home even at these temperate latitudes.

Scientists believe climate change is the driving force behind a crash in the numbers of kittiwakes, a seabird species which used to thrive in northern Scotland. The birds are doing so badly that there are fears some colonies could disappear entirely.

The Royal Society for the Protection of Birds (RSPB) is the UK’s largest nature conservation charity. In a report to mark the publication on 31 March by the Intergovernmental Panel on Climate Change (IPCC) of its latest findings, the RSPB says that on current trends kittiwakes face extinction from areas that were once core strongholds.

It says that since 2000 kittiwake numbers have declined by 87% on Orkney and Shetland, two island groups north of the Scottish mainland. The islands were once home to thriving cliff colonies of thousands of birds, but today, the RSPB says, many cliffs are virtually empty in the breeding season.

It says research shows that sea temperature changes are affecting the availability of the birds’ preferred prey, small fish called sandeels.

Leadership challenge

Paul Walton, head of habitats and species for RSPB Scotland, says: “Ten years ago Marwick Head on Orkney was a thriving seabird city – but now it looks like a ghost town. Evidence points to rising sea surface temperatures driving huge declines and species shifts in plankton populations. This is the food of sandeels, and the sandeels are food for the birds.”

Two other seabirds are declining sharply. Razorbills are down 57% from a total of 2,228 in 2000 to just 966 in 2013, and guillemots have fallen by 46% during the same period.

The RSPB wants the Scottish Government to designate key seabird feeding sites as marine protected areas. But it says a much bigger challenge is to persuade world leaders to heed the warnings in the IPCC report and do more to tackle climate change.

Other UK wildlife and habitats are also threatened by climate change. Machair is a rare, wildlife-rich coastal grassland, mostly found on Scottish islands,  and home to a traditional agricultural system that works in close harmony with nature. Working the machair is a big part of Gaelic culture, supporting corncrakes, ringed plovers, dunlins and great yellow bumblebees.

The machair is singled out in the IPCC report as one of the habitats most threatened by climate change. The IPCC says rising sea-levels, and the increased risk of storms and flooding, will mean the land becomes increasingly eroded.

Compounding the pressure

Another British bird of concern to the RSPB is the Dartford warbler, found on the heathlands of southern England and very sensitive to the cold. The species has been steadily moving northwards, apparently because of climate change. It is declining on the southern edge of its range in Spain, and in the UK conservationists are working hard to create new heathland habitat for the birds to move into.

Dotterels are birds which breed only on the highest mountain tops of Scotland. Their numbers have fallen from 630 breeding males in 1999 to 423 in 2011. Again, the RSPB believes, climate change is the culprit.

Martin Harper, the RSPB’s conservation director, says: “Kittiwakes, dotterels and Dartford warblers are three examples of wildlife being affected on our doorstep, but further afield the picture is stark for a whole range of species.

“Climate change will compound the many existing pressures on wildlife including habitat destruction, the introduction of non-native invasive species, over-exploitation and pollution.

“The overwhelming scientific consensus suggests that unless we take urgent action to reduce our greenhouse gas emissions, climate change will commit many species to extinction this century. The silent kittiwake colonies on Orkney should be a warning.” – Climate News Network

Human activities ’caused record Oz heat’

March 24, 2014 in Australia, El Niño, Extreme weather, Forecasting, Heatwave, Ocean Warming, World Meteorological Organization

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Sanctuary for some: the summer of 2013 was a grim time for both humans and wildlife Image: By Австралиец via Wikimedia Commons

Sanctuary for some: the summer of 2013 was a grim time for both humans and wildlife
Image: By Австралиец via Wikimedia Commons

By Alex Kirby

Australia’s 2013 summer was the hottest on record only because of human influences on the climate,  meteorologists say. They report that people’s activities raised the likelihood of a record by about five times.

LONDON, 24 March – Australian researchers are in no doubt about what happened there last year. The country’s Bureau of Meteorology is a model of clarity: “2013 was Australia’s warmest year on record. Persistent and widespread warmth throughout the year led to record-breaking temperatures and several severe bushfires. Nationally-averaged rainfall was slightly below average.”

Now two Australian scientists say it is virtually certain that no records would have been broken had it not been for the influence on the climate of humans. They even put a figure on it: people, they say, raised the stakes about five times.

The World Meteorological Organization devotes a section in its report, WMO statement on the status of the global climate in 2013, to the scientists’ peer-reviewed case study, undertaken by a team at the ARC Centre of Excellence for Climate System Science at the University of Melbourne. It was adapted from an article originally published in the journal Geophysical Research Letters,

The study used nine global climate models to investigate whether changes in the probability of extreme Australian summer temperatures were due to human influences.

More frequent extremes ahead

It concluded: “Comparing climate model simulations with and without human factors shows that the record hot Australian summer of 2012/13 was about five times as likely as a result of human-induced influence on climate, and that the record hot calendar year of 2013 would have been virtually impossible without human contributions of heat-trapping gases, illustrating that some extreme events are becoming much more likely due to climate change.”

The report also strikes a warning note: “These types of extreme Australian summers become even more frequent in simulations of the future under further global warming.”.

It says last year was notable as well because it was marked by what scientists call “neutral to weak La Niña ENSO conditions”, which would normally be expected to produce cooler temperatures across Australia, not hotter. El Niño is characterized by unusually warm temperatures and La Niña by unusually cool ones in the equatorial Pacific.

Before 2013 six of the eight hottest Australian summers occurred during El Niño years. The WMO says natural ENSO variations are very unlikely to explain the record 2013 Australian heat.

“There is no standstill in global warming…The laws of physics are non-negotiable”

Introducng the report the WMO secretary-general, Michel Jarraud, said many of the extreme events of 2013 were consistent with what we would expect as a result of human-induced climate change. And he repeated his insistence that claims of a pause in climate change were mistaken.

There is no standstill in global warming. The warming of our oceans has accelerated, and at lower depths. More than 90% of the excess energy trapped by greenhouse gases is stored in the oceans.

“Levels of these greenhouse gases are at record levels, meaning that our atmosphere and oceans will continue to warm for centuries to come. The laws of physics are non-negotiable.”

The report says 13 of the 14 warmest years on record have all occurred during this century, and each of the last three decades has been warmer than the previous one, culminating with 2001-2010 as the warmest decade on record. It confirms that 2013 tied with 2007 as the sixth warmest year on record, continuing the long-term global warming trend.

Temperatures in many parts of the southern hemisphere were especially warm, and Australia was not the only country to feel the impact: Argentina had its second hottest year on record.- Climate News Network

Climate science ‘is beyond argument’

March 17, 2014 in Arctic, Business, Carbon, Climate deniers, Deep Ocean, Economy, Fish, Food security, Global Ocean Commission, Ice Loss, Marine ecology, Ocean acidification, Ocean Warming, Polar ice, Pollution, Science

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Not as sunny as it seems: The ocean is under attack on many fronts, with climate change foremost among them Image: kein via Wikimedia Commons

Not as sunny as it seems: The ocean is under attack on many fronts, with climate change foremost among them
Image: kein via Wikimedia Commons

By Alex Kirby

The Global Ocean Commission says climate change is one of the key threats to the health of the world’s marine life, which it says faces multiple pressures in a warming world.

HONG KONG, 17 March - South Africa’s former Finance Minister, Trevor Manuel, has derided those who deny the scientific argument that climate change is an urgent problem caused largely by human activity.

He told journalists here: “The science is now incontrovertible. There are a few people in the world who deny it, but they are mainly in lunatic asylums.”

Mr Manuel is one of three co-chairs of the Global Ocean Commission, a panel of global leaders who have just ended a meeting here to finalise the proposals they will present to the United Nations in June.

The meeting agreed that another key threat to the world’s oceans is overfishing and the subsidies which help to make it possible. It says this, and the other factors causing ocean degradation, threaten the food security of as many as 500 million people.

It is deeply worried about pollution. With plastic remains now so pervasive that they are found even in deep seafloor sediments, Mr Manuel said, it sometimes seemed that “you might as well not bother to buy seafood at all – just buy the plastic bag it comes in and eat that.”

Shells corroded

The Commission says climate change threatens the oceans in three main ways: by raising the temperature of the water; by reducing its oxygen content; and by increasing its acidity. Antarctic pteropods, small sea snails also known as sea butterflies, are already being found with severely corroded shells because of acidification, and larger creatures, including bigger shellfish and corals, are likely to be seriously affected.

Another of the co-chairs, José María Figueres, the former president of Costa Rica, told the Climate News Network the Commission was concerned at the prospect of exploitation of the high seas in the Arctic as the region’s sea ice continues to melt.

He said: “Beyond Arctic countries’ EEZs (exclusive economic zones stretching 200 nautical miles from the coast), the melting will leave us with a doughnut-shaped hole in the Arctic high seas, which are not under international control.

“Some nations are now looking to explore there for fish, minerals, valuable biodiversity and other resources. I believe we should not go down that route.

We should listen to the science and follow the precautionary principle, keeping this pristine area off-limits for exploitation until we understand the consequences.

Coalition builders

“We’re already pushing the high seas to the limit. We don’t need to push them over the edge by a lack of proper precaution in the Arctic.”

He said: “The jury is still out on whether we have 20 or 30 years ahead as a window of opportunity to act. But why wait? Listen to the science, which is overwhelming, and to the economics, which are sound.”

Describing the Commission as “not just a bunch of treehuggers, but a group that’s grounded itself in good sound economics”, Mr Figueres said the recommendations it planned to present to the UN on 24 June would represent about 20% of its work. The other 80% would involve building coalitions around each recommendation: there are expected to be no more than 10 in total.

The Commission’s third co-chair is the UK’s former Foreign Secretary, David Miliband. He told the Network: “Answers that sit on a shelf are a waste of time, and people who are positively inclined to protect the oceans are held back by institutional inertia.

“But the interplay between climate change and ocean damage is rising, and it very much needs to. The science of most of the last half-century shows us how we’ve been playing tricks with nature.” – Climate News Network

Arctic melt speeding up

March 9, 2014 in Arctic, Climate Sensitivity, Deep Ocean, Greenland, Marine ecology, Ocean Warming, Polar ice, Solar energy

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Measuring the sun's reflectivity in the Arctic Image: NASA/Kathryn Hansen via Wikimedia Commons

Measuring the sun’s reflectivity in the Arctic
Image: NASA/Kathryn Hansen via Wikimedia Commons

By Tim Radford

It’s long been established that Arctic ice is on the retreat but it’s the pace of change that’s surprising scientists: latest studies show the region is at its warmest for 40,000 years. 

LONDON, 9 March - Ice in the Arctic continues to retreat. The season without ice is getting longer by an average of five days every 10 years, according to a new study in Geophysical Research Letters.  And in some regions of the Arctic, the autumn freeze is now up to 11 days later every decade.

This means that a greater proportion of the polar region for a longer timespan no longer reflects sunlight but absorbs it. This change in albedo – the scientist’s term for a planet’s reflectivity – means that open sea absorbs radiation, stays warmer, and freezes again ever later.

Warming accelerates

None of this is news: sea ice in the Arctic has been both retreating and thinning in volume for four decades. Researchers have tracked the retreat of the snow line to find tiny plants exposed that had been frozen over 40,000 years ago: the implication is that the Arctic is warmer now than it has been for 40 millennia.

This warming threatens the animals that depend for their existence on a stable cycle of seasons  and is accelerating at such a rate that the polar ocean could be entirely free of ice in late summer in the next four decades.

So Julienne Stroeve, of University College London and her colleagues have provided yet further confirmation of an increasing rate of change in the region in their latest study.

The scientists examined satellite imagery of the Arctic for the last 30 years, on 25 square kilometer grid, to work out the albedo of each square for every month they had data.

Their headline figure of five days is an average: in fact the pattern of freeze and thaw in the Arctic varies. In one region the melt season has been extended by 13 days, in another the melt season is actually getting shorter.

Energy increases

This increasing exposure to summer sunlight means that ever greater quantities of energy are being absorbed: several times the energy of the atomic bomb dropped on Hiroshima hits every square kilometer of the open Arctic Ocean.

“The extent of sea ice in the Arctic has been declining for the last four decades,” said Professor Stroeve, “and the timing of when melt begins and ends has a large impact on the amount of ice lost each summer.

With the Arctic region becoming more accessible for longer periods of time, there is a growing need for improved prediction of when the ice retreats and reforms in the water.” - Climate News Network

 

Cold and warm polar water mixing slows

March 4, 2014 in Antarctic, Convection, Deep Ocean, Ocean Warming, Polar ice

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A large iceberg calved from an Antarctic glacier: Weakening convection will make it slower to melt Image: NASA ICE (uploaded by russavia) via Wikimedia Commons

A large iceberg calved from an Antarctic glacier: Weakening convection will make it slower to melt
Image: NASA ICE (uploaded by russavia) via Wikimedia Commons

By Tim Radford

The process that sends cold surface Antarctic water to the warmer depths, redistributing heat and storing carbon, is now faltering, scientists say – because of climate change.

LONDON, 4 March – Global warming could have dramatic consequences for ocean circulation in the Antarctic, according to new research in Nature Climate Change. It could reduce convection in the Southern Ocean.

Convection is the process that turns over a vast body of sea water, sending the fresh water from melted ice to the depths, while bringing warmer, more saline waters to the surface. Since the ocean is part of the global machinery for redistributing heat and storing carbon, any change in the pattern of movement could have profound significance.

Casimir de Lavergne and colleagues from McGill University in Canada and the University of Pennsylvania in the US analysed a 60-year sequence of satellite observations and direct measurements in the Ross and Weddell seas and coupled these with simulated studies of ocean behaviour. They found that the surface ocean had become less saline: cold fresh water now forms a kind of lid on the Southern Ocean surface to trap warmer salt water below.

What had historically been an upwelling of warmer water had dramatic consequences for the Weddel Sea ice pack: in the mid-1970s it permitted a 250,000 square kilometre stretch of open water called a polynya that stayed open for three full winters before it closed. The polynya has not re-opened in 40 years.

While it was open, the cold, surface dense waters of the polynya sank 3,000 metres, and became new deep ocean bottom water, and this sinking, while it lasted, was on a massive scale: at least twice the flow of all the rivers of the terrestrial world.

For decades, oceanographers and glaciologists regarded the event as naturally rare, a curiosity rather than an important part of the ocean ecosystem. The latest study however presents a different picture.

Few escape opportunities

The first orbiting satellites may have recorded, for the first time in 1974, a regular but steadily weakening feature of the Southern Ocean, a phenomenon that was  weakening because of climate change. It also means that heat stored in the deep ocean has been unable to melt the wintertime icepack.

“Deep ocean waters only mix directly to the surface in a few small regions of the global ocean, so this has effectively shut off one of the main conduits for the deep ocean heat to escape,” said de Lavergne.

The team’s models showed that, before the Industrial Revolution, significant ocean convection occurred in the region. Under a high emissions scenario, the models showed a decrease in the strength of this convection. In seven of the team’s 25 computer models, deep circulation stopped entirely by 2030.

The team’s computer simulations also predict greater snow and rainfall in the Southern Ocean as atmospheric carbon dioxide increases.

“A warming planet will see dryer regions become dryer and wetter regions become wetter. True to form, the polar Southern Ocean – as a wet place – has indeed become wetter,” said Jaime Palter of McGill, a co-author. “And as a response to surface ocean freshening, the polynyas simulated by the models also disappeared.” – Climate News Network

Hotter extremes belie warming ‘pause’

March 1, 2014 in El Niño, Ocean Warming, Trade Winds, Warming slowdown

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California's Death Valley is among the world's hottest places - but many are steadily getting hotter still Image: Pandat at de.wikipedia via Wikimedia Commons

California’s Death Valley is among the world’s hottest places – but many are steadily getting hotter still
Image: Pandat at de.wikipedia via Wikimedia Commons

By Tim Radford

Increasing and more frequent extremes of heat affecting wider regions, scientists say, are evidence that it is misleading to claim that climate change has paused.

LONDON, 1 March – If global warming has paused, nobody told the thermometer. Although global average temperature rises have not kept pace with greenhouse gas emissions in the last decade, the mercury has been higher than ever for longer than ever over increasingly larger areas of land, according to a new study in Nature Climate Change.

Sonia Seneviratne from the Swiss Federal Institute of Technology in Zurich and colleagues in Australia and Canada chose not to look at averages but at extremes of temperature. The scientists examined daytime extremes from 1979 onwards, and compared the temperatures of any particular day anywhere to an average of daily temperatures between 1979 and 2012, to identify the hottest 10%. Any region might normally expect 36.5 hottest days in a year; that is, hotter than the average.

Then they looked more closely at temperatures from 1997 to 2012. Regions that experienced 10, 30 or 50 extremely hot days above this average saw the greatest upward trends in extreme hot days over time – and over area. That is, not only were people experiencing greater heat extremes, but they were experiencing them over more days and over more extended regions.

And this consistent upward trend persisted right through the so-called “hiatus” of 1998 to 2012. The year 1998, at the time the hottest ever, coincided with a major El Niño event, the peak of a natural cycle of warmth and cooling in the Pacific.

Extreme extremes change most

Thereafter, although 13 of the 14 warmest-ever years have occurred this century, the rate of increase in warming as a global average has fallen. Climate sceptics used the trend to argue that global warming was an illusion, or part of a natural cycle. Dr Seneviratne and her colleagues do not see it that way.

“It quickly became clear the so-called ‘hiatus’ in global average temperatures did not stop the rise in the number, intensity and area of extremely hot days,” said Lisa Alexander of Australia’s Centre of Excellence for Climate System Science.

“Our research has found a steep upward tendency in the temperatures and number of extremely hot days over land and the area they impact, despite the complete absence of a strong El Niño.”

And her colleague Markus Donat added: “There has been no pause in the increase of warmest daily extremes over the land and the most extreme of the extreme conditions are showing the largest change.

“Another interesting aspect of our research was that those regions that normally saw 50 or more excessive hot days in a year saw the greatest increases in land area impact and the frequency of hot days. In short, the hottest extremes got hotter and the events happened more often.”

‘Illusory’ pause

However, perhaps because the world is mostly ocean, and the extremes have been measured over land, the average, year-on-year rises in temperatures have been lower in the last decade than in previous decades. There have been a number of inconclusive explanations for this phenomenon.

Cyclic changes in trade winds are one explanation; another is that the heat is there, but has been stored in the deep ocean, where measurements are not systematically taken. It’s there somewhere, waiting to be found.

And US scientists argue in the latest issue of the journal Science that the oceans may have an even bigger influence on climate than anybody foresaw, and that persistent cool conditions in the tropical Pacific may be behind what they call the “pause in global warming since 2000.”

But the latest Nature Climate Change paper puts the case that this pause or hiatus is illusory with – for a scientific paper – unusual clarity. “Based on existing observational evidence,” the authors say, “we highlight that the term pause, as applied to the recent evolution of global annual mean temperatures, is ill-chosen and even misleading in the context of climate change.

“Indeed, an apparently static global mean temperature can mask large trends in temperatures at both regional and seasonal scales.” – Climate News Network

US urges fishing ban in melting Arctic

February 24, 2014 in Adaptation, Arctic, Fish, Indigenous peoples, Marine ecology, Ocean Warming

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A US Coastguard vessel patrols the Arctic Ocean: Once the ice goes, the trawlers will not be far behind Image: PA1 Timothy Tamargo via Wikimedia Commons

A US Coast Guard vessel patrols the Arctic Ocean: Once the ice goes, the trawlers will not be far behind
Image: PA1 Timothy Tamargo via Wikimedia Commons

By Alex Kirby

Washington is urging countries that share the Arctic to ban commercial fishing in the offshore Arctic Ocean, something that will soon be possible for the first time in human history as the ice melts.

LONDON, 24 February – The countries that ring the Arctic Ocean will soon face a dilemma: can they risk commercial fishing fleets shooting their nets in those soon-to-be-ice-free seas?

Before long – quite possibly before mid-century – the Arctic Ocean will be free of ice during part of each summer, scientists are now saying confidently. For better or worse that will open up huge opportunities for shipping and hydrocarbon exploitation. And for the first time in recorded history it will allow the fishing boats access to whatever has lived undisturbed until now beneath the ice.

A three-day meeting began today in Nuuk, the capital of Greenland, where US officials are hoping to persuade the other nations which border the Arctic Ocean to introduce a moratorium on high seas fishing there (the other members of the group are Canada, Russia and Norway).

David Benton, of the US Arctic Research Commission (USARC), said the Americans were proposing an agreement “that would close the international waters of the Arctic Ocean to commercial fishing until there is a good scientific foundation on which to base management of any potential fishing”.

All coastal countries control fisheries within 200 miles of their own coastlines. The high seas beyond that limit belong to no country and can be protected only by international agreement.

Once the five Arctic nations have agreed a fishing moratorium, Benton said, they would then approach other countries with major commercial fishing fleets, such as China, Japan and Korea, to negotiate full protection for the central Arctic Ocean.

Previous ban

The Arctic was experiencing a fairly rapid rate of change, said Benton, as the permanent ice melted. “That’s potentially causing large changes in the ecosystem, but we don’t understand what’s going on up there. If we want to do things right, this is the approach we should be taking.”

In 2009, the US adopted its own Arctic Fishery Management Plan, closing American waters north of Alaska to commercial fishing until scientific research proves that the fishery is sustainable. Scott Highleyman, director of the international Arctic program for the Pew Charitable Trusts, said that had been a precaution that took account of the way warming was changing the Arctic ecosystem faster than science could keep up with it.

He told the Los Angeles Times: “There are no stock surveys or scientific assessments for fish there. You don’t want to fish a place where you don’t know the fish population dynamics. Any time we’ve done that, it led to catastrophic overfishing.” One example, Highleyman said, is the New England Atlantic cod fishery, which was shut down in the 1980s due to overfishing, costing 50,000 jobs.

An open letter to the Arctic governments, signed by 2,000 scientists from around the world, says that if the Ocean is overfished that will damage species that live there, including seals, whales and polar bears, and the people who use them for food.

“Until recently, the region has been covered with sea ice throughout the year, creating a physical barrier to the fisheries,” the scientists wrote. “A commercial fishery in the central Arctic Ocean is now possible and feasible.” – Climate News Network

Cat litter killer in the whales of the North

February 14, 2014 in Adaptation, Arctic, Atlantic, Disease, Ice Loss, Indigenous peoples, Marine ecology, Ocean Warming, Polar ice, Wildlife

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Blissful domesticity: But even domestic cats can spread Toxoplasma gondii

Blissful domesticity: But even domestic cats can spread Toxoplasma gondii

By Tim Radford

One consequence of a warming climate is new patterns of disease, and researchers have identified two parasites formerly unknown in the Arctic in marine mammals.

CHICAGO, 14 February – The great Arctic thaw – up to 50% of sea ice by area and 75% by volume in the summer season – could be offering new opportunities for one of the planet’s most successful parasites. Toxoplasma gondii, an infection spread by almost all cat species, has been identified for the first time in the western Arctic Beluga whale.

Toxoplasma is found almost everywhere that cats settle: domestic pets, ocelots, cougar, wild cats all carry and spread oocysts of the parasite (structures it uses to transfer to new hosts) in their faeces, to be spread further with discarded cat litter.

The parasite is notoriously hard to kill. Scientists store their samples in sulphuric acid, and the creature can survive unharmed in bleach. It is, however, routinely killed by freezing conditions, or boiling water.

The suspicion is that with the steady, sustained warming of the Arctic over the past 30 years, chiefly because of a buildup of carbon dioxide in the atmosphere, the retreat of the ice has begun to allow new traffic in parasite infections.

Another parasitic killer, a new strain called Sarcocystis pinnipedi, normally found only in the highest, iciest latitudes, has been linked with mass deaths too: 406 grey seals died in 2012 in the north Atlantic. It has also been observed to kill Steller’s sea lions, Hawaiian monk seals, walruses, grizzly bears and polar bears as far south as British Columbia.

In the case of Toxoplasma, warming polar summers could have created conditions in which the parasite could find new warm-blooded hosts further north. In the case of the second parasite, the loss of ice has meant a greater mixing of species, and allowed Sarcocystis to find new hosts in warmer waters.

Cause of blindness

“Ice is a major barrier for pathogens”, Michael Grigg, of the US National Institutes of Health told the American Association for the Advancement of Science annual meeting here. “What we are seeing with the big thaw is the liberation of pathogens gaining access to vulnerable new hosts and wreaking havoc.”

Toxoplasma can also infect people: it is the leading cause of infectious blindness in humans, and can be dangerous to unborn children and to people with compromised immunity.

It has been found in human communities in northern Quebec, perhaps spread by the consumption of dried seal meat. The discovery of Toxoplasma in Beluga whales has begun to worry health officials. Belugas are part of the traditional diet of the Inuit hunters of the far North.

Seals, walruses and polar bears are all what scientists like to call “ice obligate animals”: the ice sheet provides them with their preferred habitat. With the loss of the ice, new species are colonizing the Arctic, and those creatures that cannot now use the ice sheet have been forced to invade new habitats.

“Marine mammals can act as ecosystem sentinels because they respond to climate change through shifts in distribution, timing of their movements and feeding locations”, said Sue Moore of the US National Oceanic and Atmospheric Administration. “These long-lived mammals also reflect changes to the ecosystem in their shifts in diet, body condition and physical health.” – Climate News Network

Equatorial fish feel the heat

February 12, 2014 in Adaptation, Fish, Food security, Indonesia, Marine ecology, Ocean Warming, Warming, Wildlife

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Weaving through the coral: Small fish like these are important sources of food for larger reef species Image: D. Dixson

Weaving through the coral: Small fish like these are important sources of food for larger reef species
Image: D. Dixson

By Alex Kirby

Many species of fish living near the Equator are sensitive to variations in heat and will not thrive in the warmer oceans of the future, scientists in Australia have found.

LONDON, 12 February – Lying in a hot bath may be a pleasant experience, because you can always get out when you’ve had enough. For some of the fish that swim in equatorial seas, though, that is not an option: climate change threatens to make the water not just uncomfortable, but unendurable.

An international team of researchers based in Australia reports in Global Change Biology that the rapid pace of climate change is threatening the future of some of the fish which live near the Equator.

Over a 14-day period the team tested four species of damsel fish and two of cardinal fish. They say: “Our results indicate that low-latitude reef fish populations are living close to their thermal optima and may be more sensitive to ocean warming than higher-latitude populations.”

“Our studies found that one species of fish could not even survive in water just 3°C warmer than it lives in now”, says the lead author of the study, Dr Jodie Rummer from the ARC Centre of Excellence for Coral Reef Studies (Coral CoE) at James Cook University in Queensland.

Dr Rummer and her colleagues studied six common species living on coral reefs near the Equator. She says many species in this region experience only a very narrow range of temperatures throughout their lives, and so are probably adapted to perform best at those temperatures.

The world’s oceans are projected to warm by 2-3°C by the end of this century. “Such an increase in warming leads to a loss of performance”, Dr Rummer said. “Already, we found four species of fish are living at or above the temperatures at which they function best.”

Breeding compromised

The team measured the rates at which fish use oxygen across different temperatures – at rest and during maximal performance. The results showed that in warmer water fish lose their ability to perform properly. In the wild this would limit activities crucial to survival, such as evading predators, finding food, and finding the energy to breed.

With many of the Earth’s equatorial wild populations now living close to their thermal limits, there will be serious consequences if some – like the fish the researchers studied – cannot adapt to the speed at which the oceans are warming.

The response of many species to increasing warmth is to migrate to somewhere that suits them better, which could help to drain the equatorial oceans of fish which play a key role there. Dr Rummer suggests there will be declines in fish populations as species move away from the Equator to find refuge in areas with more agreeable temperatures.

“This will have a substantial impact on the human societies that depend on these fish,” she says. Many developing countries are in the equatorial zone, and fish are central to the livelihoods and survival of millions of people, including many in Indonesia and south-east Asia.

With rapid climate change, the scientists say, understanding the link between an organism and its environment is crucial to developing management strategies to conserve biodiversity and to allow the sustainable use of marine fisheries. This is especially urgent for ensuring food security for people. – Climate News Network

Trade winds draw ‘missing’ warmth to deep ocean

February 10, 2014 in Deep Ocean, Ocean Warming, Pacific Ocean, Trade Winds, Warming slowdown

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The trade winds make their mark on Hawaii - and they may explain where the "missing" warmth has gone Image: Richard B. Mieremet, Senior Advisor, NOAA OSDIA

The trade winds make their mark on Hawaii – and they may explain where the “missing” warmth has gone
Image: Richard B. Mieremet, Senior Advisor, NOAA OSDIA

By Tim Radford

Contrary to some reports, global warming hasn’t stopped or slowed at all, new research suggests. The trade winds have simply carried the heat into the Pacific Ocean – temporarily.

LONDON, 10 February – Australian and US scientists think they know where a lot of global warming has been concentrated: it has been tucked away below the surface waters of the western Pacific Ocean. And the agency that took the heat out of the atmosphere and transferred it into a liquid form could have been the equatorial trade winds.

Matthew England from the Australian Centre of Excellence for Climate System Science and colleagues report in Nature Climate Change that a dramatic acceleration in the winds has drawn heat from the atmosphere and transferred it to the ocean: cooler waters have risen to the surface to mask the transaction.

Climate sceptics – and some climate scientists – talk about a slowdown, or a pause, or a hiatus in global warming. In fact, temperatures have gone on rising and 13 of the 14 warmest years ever recorded have all occurred since 2000. But the rate of rise in global average temperatures since 2000 has not been as fast as the rate during the 1980s and 1990s.

Since greenhouse gas levels have continued to rise, and since scientists are sure of their atmospheric physics, then there was some “missing heat” to be accounted for.

Researchers have variously suggested that a puzzling increase in deep ocean temperatures could be one explanation or that perhaps the unevenness of temperature measurements around the planet might be another. But both suggestions were hypotheses: nobody had an answer that could be tested by any kind of experiment.

Slower rate

Professor England and colleagues worked with observed winds, surface air temperatures, and a set of ocean climate models to calculate what may have happened.

The global warming story has always been one of fits and starts: a warming that ought to have been observed 70 years ago stalled between 1940 and 1970, and when it resumed, did so in fits and starts. The overall trend continued upward, but the rate of rise slowed noticeably during the last decade.

Ocean circulation loops are driven by winds, and speed up as the winds intensify. Cool waters well up, warm waters descend. And intensify is just what the trade winds have done. They began strengthening during the 1990s, a process which continues today. Once the researchers added the trade winds to their calculations, the global average temperatures looked very like the observations during the hiatus.

They also found that four-fifths of the surface temperature cooling occurred after 2000, which confirmed that wind acceleration was the key contributor.

“Scientists have long suspected that extra ocean heat uptake has slowed the rise of global average temperatures, but the mechanism behind the hiatus remained unclear”, said Professor England.

Rapid rise on the way

“But the heat uptake is by no means permanent: when the trade wind strength returns to normal – as it inevitably will – our research suggests heat will quickly accumulate in the atmosphere. So global temperatures look set to rise rapidly out of the hiatus, returning to the levels projected within as little as a decade.”

The same mechanism could explain the slowdown between 1940 and 1970. In 1938, the British scientist G S Callendar argued that rising carbon dioxide levels should mean global warming but the evidence proved elusive, perhaps because the trade winds accelerated during those decades.

Richard Allan, professor of climate science at the University of Reading in the UK, said the current slowdown was only a temporary reprieve.

“Measurements from satellites and ocean buoys show that the planet is absorbing more heat than it is radiating out to space and the heat is building up in the oceans.

“This new research suggests that when the trade winds weaken again, the planet can expect rapid warming of the surface to resume, as greenhouse gas concentrations continue to rise.” – Climate News Network