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Early springs surprise many species

April 7, 2014 in Adaptation, Arctic, Climate, Polar ice, Species loss, Warming, Wildlife

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Roe deer numbers have been particularly hard hit by seasonal disruption.  Image: Marek Szczepanek via Wikimedia Commons

Roe deer numbers have been particularly hard hit by seasonal disruption.
Image: Marek Szczepanek via Wikimedia Commons

By Tim Radford

As seasonal change suffers ever more disruption, many species are struggling to adapt quickly enough.

LONDON, 7 April – Spring is arriving earlier. This is not necessarily welcome news for Arctic creatures or the roe deer of France. It could be awkward for flower festival organisers as well.

Julienne Stroeve of the US National Snow and Ice Data Centre and colleagues will report in Geophysical Research Letters that the length of the Arctic melt season is growing by several days each decade. When the melt starts earlier, the Arctic Ocean absorbs more radiation: enough in some places to melt four feet in thickness from the Arctic ice cap.

“The lengthening of the melt season is allowing for more of the sun’s energy to get stored in the oceans and increase ice melt during the summer, overall weakening the sea ice cover,” says Stroeve. The Arctic sea ice has now been in decline for four decades.

The seven lowest September sea ice extents in the satellite record have all occurred in the last seven years. A new examination of satellite imagery and data from 1979 to the present shows that the Beaufort and Chukchi Seas are freezing up between six and 11 days later per decade. But the earlier melt is more ominous than the later freeze: the sun is higher and brighter, and delivers more warmth to the seas.

Festival disruption

The earlier spring presents no problems for many plants but it may not be much fun for the organisers of flower festivals who like to announce their events well in advance. Tim Sparks of Coventry University reports in the journal Climate Research that over its 46-year history, the Thriplow Daffodil Weekend in Cambridgeshire in eastern England has been forced to bring its dates forward by 26 days.

The event can attract up to 10,000 visitors, and has raised £300,000 (US $500,000) for charity, so it clearly helps the organisers to set up some advance publicity. Since 1969, mean temperatures in March and April in the UK have risen by 1.8°C.

“The study represents one of the first solid pieces of evidence of flower tourism having to adapt to climate change,” said Professor Sparks. “The issues faced by Thriplow are a microcosm of the wider picture.”

Flower festivals may be able to adapt. Sadly, the roe deer of Champagne have yet to get the message about climate change. To flourish, both nectar seekers and herbivores have to time their breeding patterns to the surge in plant growth.

Three French scientists looked at records of a population of roe deer in the Champagne region of France, and found that although spring has been arriving increasingly earlier, the fawns are being born at around the same dates as they were 27 years ago, and their survival rate is falling, they report in the Public Library of Science journal PLOS Biology. Overall, the roe deer population in the region is also in decline.

Great tits have kept up with climate change, because reproduction is cued by temperature, so they are around at the same time as the explosion in food sources. What sets the biological pace for roe deer is day length, the authors think, and this is not affected by climate change. - Climate News Network

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

Malarial mosquitoes flying higher

March 15, 2014 in Africa, Climate, Disease, Mountains, Warming

 

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The Anopheles mosquito. With a warming climate, it could fly higher Image: James Gathany via Wikimedia Commons

The Anopheles gambiae mosquito. With a warming climate, it could fly higher
Image: James Gathany via Wikimedia Commons

By Tim Radford

Scientists are finding that malaria carrying mosquitoes can survive in higher regions in warmer periods. With changes in climate that’s bad news. 

LONDON, 15 March - Things are looking up for the little parasite that infects 200 million people a year, and kills more than 600,000 of them.

As global temperatures rise, so will the altitude at which the Anopheles mosquito and its plasmodium parasite can survive, and so will the numbers at risk from malaria.

The global war against malaria has always been an uphill struggle, but populations in highland regions have usually been safe, because the parasite cannot replicate at low temperatures.

Disease spread

But Amir Siraj of the University of Denver in Colorado in the US and colleagues in the UK and Ethiopia report in the journal Science that they’ve started to consider the effect of climate change on the spread of the disease.

Projections of hazards such as these are difficult: the likelihood of infection can depend on steps civil, national and international health authorities may take, the preparedness of communities depends on spraying programmes and the availability of drugs, and the numbers at risk alter as populations grow and economies develop.

All malaria needs is somewhere warm and wet, and a steady supply of potential hosts. The disease was once endemic in mild, low-lying or marshy areas of Europe (the name comes from the Italian mal aria, or bad air).

It can be controlled by spraying, and by public education. But it remains an enduring hazard in Africa, parts of Asia and South America. Upland communities, however, have tended to be safe.

Data search

But the Denver team decided to forget about all the complex possibilities and just look at some very precise data from 124 municipalities in Antioquia in western Colombia between 1990 and 2005, and 159 administrative units in the Debre Zeit region of Ethiopia from 1993 to 2005.

They reasoned that a match of seasonal temperatures and reported cases would tell them what to expect.

Sure enough, they found that during warmer years, there were more reported cases of malaria in both countries. The “median altitude” at which cases were registered shifted accordingly with annual temperatures. That gave them enough information to consider some alarming possibilities.

In a previous study, scientists predicted that a 1°C rise in global average temperatures could bring an additional three million cases a year in Ethiopia among children under 15. As average temperatures rise, so will the numbers of potential victims soar, and so will the need for investment in mitigation and insect control.

“With progressive global warming, malaria will creep up the mountains and spread to new high altitude areas,” said Menno Bouma of the London School of Hygiene and Tropical Medicine, one of the authors.

“And because these populations lack protective immunity, they will be particularly vulnerable.”- Climate News Network

 

 

Mild climate spurs Genghis Khan’s cavalry

March 12, 2014 in Archaeology, Climate, Drought, Extreme weather, Livestock, Temperature Increase

 

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Mongol cavalry gallop across Asia - maybe assisted by changes in climate Image: Sayf al-Vahidi via Wikimedia Commons

Mongol cavalry gallop across Asia – maybe assisted by changes in climate
Image: Sayf al-Vahidi via Wikimedia Commons

By Tim Radford

Scientists have unearthed possible evidence that climate change played a role in the expansion of the Mongol empire of Genghis Khan. They say an exceptionally warm period promoted grass growth, vital for the Mongols’ legendary horses.

LONDON, 12 March - Climate change – already implicated in the fall of Bronze Age civilisations in the Mediterranean and in the Indus Valley  - may also account for the rise of one of the most fearsome empires in history.

US researchers mapping the pattern of rainfall in medieval Mongolia think they may have identified a season of plenty that put Genghis Khan on the road towards world domination.

Archaeologists and climate scientists have identified sustained drought as a reason for the fall of the Minoan civilisation in Crete, and the decay of the Harappan culture in 1,000 years earlier. But a team from Columbia University report in the Proceedings of the National Academy of Sciences that annual growth rings in a trove of stunted larches and Siberian pines in the Khangai mountains of Mongolia tell a different story.

Rings record

The seasonal growth rings record a chronicle of harsh dry centuries dating back to 658AD. But between the years 1211 to 1230, something unusual happened.

Rain fell, and central Mongolia had one of the wettest periods in its history. The same period was unusually warm. Since those years coincide with the rise of the Mongol empire the connection suggested itself immediately: the Mongols were herdsmen and nomads.

Wet and warm weather means plenty of grass. Suddenly, tribesmen who wandered far to find grazing space had a surplus of feed, and soon of animals, including a glut of war horses and cattle.

The Mongol cavalry were famous for their horsemanship. “The weather may literally have supplied the Mongols with the horsepower they needed to do what they did,” says Neil Pederson of Columbia’s Lamont Doherty Observatory.

All conquering

For a brief period, the Mongols, led by a commander of remarkable military and political genius, and then by his descendants, conquered and ruled most of modern Russia, Korea, China, Persia, India, the Middle East and eastern Europe.

There is never just one reason for a civilisation’s rise or fall, and historians have also argued that the Mongol invasions might have been driven instead by hunger and poverty in the Mongol heartland.

So the researchers would like to back up their tree ring evidence with studies of lake sediments, analyses of historical documents and so on, to establish that the steppes really could have provided for the great khan and his horde. The jury is still out.

The tree rings also show that after the first growth of the Mongol empire, the climate returned to its normal cold dry state. In the last 40 years, temperatures have risen. And since 1990, the country has experienced a series of devastating summer droughts often followed by a more than usually long cold winter.

Modern day drought

After the last such, an estimated eight million animals died, herdsmen became impoverished, and the poorest have moved to the capital of Ulaanbaatar, which is now home to half of the nation’s 3 million people.

“That last big drought is an example of what may happen in the future, not just in Mongolia but in a lot of inner Asia,” says Pederson. “The heat is a double whammy – even if the rainfall doesn’t change, the landscape is going to get drier.”

The potential consequences for modern Mongolia, the authors warn, could be severe.- Climate News Network

 

Old Greek plays record halcyon days

March 8, 2014 in Climate, Europe, History, Weather

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The theatre at Epiidaurus, where many of the leading dramatists' plays were performed Image: plusgood via Wikimedia Commons

The theatre at Epiidaurus, where many of the leading dramatists’ plays were performed
Image: plusgood via Wikimedia Commons

By Tim Radford

History and literature provide evidence of consistently mild mid-winter weather in ancient Greece, helping climate scientists to reconstruct the past and so understand the future.

LONDON, 8 March – In fifth century Athens, in January at least, the skies were clear and the rain stayed away. The days, to use a classical reference, were halcyon.

Two Greek researchers have combed the great plays of Aeschylus, Sophocles and Euripides and the bawdy comedies of Aristophanes to deliver a long-term weather report for mid-winter days from 458 BC to 401 BC. They report in the Royal Meteorological Society’s journal Weather that, clearly, the city was a good place to hold open-air stage productions in mid-winter. Sophocles, in his masterpiece Oedipus at Colonus, actually says so:

“A distant music, pure and clear rises from green secluded vales. The constant trill of nightingales deep in their haunts of tangled vine, of sacred ivy, dark as wine, thick is the god’s inviolate wood; rich in berries and rich in fruit, the sun is curtained; the wind is mute, in winter.”

To understand the climate of the future, scientists must reconstruct the patterns of the past, long before the first formal weather records. They do this by examining pollens in lake beds, growth rings in ancient trees, ice cores and ocean muds to deliver circumstantial evidence of bygone seasons.

Balmy mid-winter

But there are also indirect references in human records: in naval log books, in medieval tax records, in monastic manuscripts, and in chronicles from Baghdad in the golden age of Islamic scholarship.

Christina Chronopoulou of the National and Kapodistrian University of Athens, and a colleague from Panteion University in the same city, decided to comb 43 surviving works performed during the Lenaia celebrations in mid-winter. They found seven clear direct and indirect references to the beneficial halcyon days of mid-winter.

The halcyon days are now a cliché but once referred to the myth of Alcyone, the grieving widow who was turned into a kingfisher by the gods, and who nested on the beach at midwinter.

But the fact the ancient Greeks routinely watched and expected to watch drama in open amphitheatres during the Attic month of Gamelion, which ran from 15 January to 15 February, provides indirect confirmation of good weather. Halcyon days, say the authors, are “atypical winter-time weather periods characterized by sunny and calm conditions” and the result of a stagnant high-pressure system that dominates the area at such a time of year.

Observant dramatists

And, as they worked through some of the great plays, they found enduring references to clear skies: in Agamemnon, by Aeschylus, in 458 BC a character spends his nights on the roof “to know thoroughly the throng of stars…” Aristophanes in The Birds in 414 BC describes a wedding.  Attic weddings lasted for three days and were performed in the open air, another indicator of mellow conditions. The Birds also contains references to a “skiadeion”, a parasol, an umbrella to provide shade from the sun, rather than shelter from the rain.

Euripides in Medea in 431 BC mentions “the temperate and sweet breezes” while Aristophanes in The Frogs in 405 BC actually addresses “you halcyons who chatter by the ever-flowing waves.”

“Combining the fact that dramatic contests were held in mid-winter without any indication of postponement, and references from the drama about clear weather and mild winters, we can assume that those particular days of almost every January were summery in the 5th and maybe the 4th centuries BC,” said Dr Chronopoulou. – Climate News Network

India’s diesel fumes fuel glacier melt

March 6, 2014 in Black Carbon, Climate, Glaciers, Himalayas, Ice Loss, Mountains, Pollution

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Nanda Devi, one of the highest peaks in the Himalayas: Air pollution from the cities is affecting the mountain glaciers Image: Anirban c* via Wikimedia Commons

Nanda Devi, one of the highest peaks in the Himalayas: Air pollution from the cities is affecting the mountain glaciers
Image: Anirban c8 via Wikimedia Commons

By Kieran Cooke

As India’s economy expands, so does pollution, particularly in the country’s major cities. Kieran Cooke, one of our editors, has recently been in Kolkata, one of the country’s biggest and most polluted population centres: he says increasing pollution is not only harming Kolkata’s citizens – it’s also a likely contributor to climate change taking place in the Himalayan region.

KOLKATA, 6 March – Being a traffic policeman in Kolkata is a life-threatening business. Not only are you at risk of being run over on the traffic-clogged roads and streets of this chaotic city of 14 million – you’re also more than likely to suffer from serious health problems due to some of the worst air pollution not just in India, but in the world.

According to a 2012 report by the New Delhi-based Centre for Science and Environment on air quality in Kolkata, seven out of every ten people in the city suffer from some form of respiratory ailment: not surprisingly, traffic policemen and the city’s thousands of street dwellers are among the high risk groups.

Air pollution, particularly related to diesel-fuelled vehicles that jam Kolkata’s roads, is also linked to the city’s unusually high levels of lung cancer.

Meanwhile the government’s own Central Pollution Control Board gives Kolkata and New Delhi the unenviable status of being joint winners of India’s most polluted city prize.

All this is not just bad news for people living in Kolkata and India’s other major urban conglomerations. The increasing air pollution in India’s cities – particularly those in the northern parts of the country – also has an impact on the degree of melt taking place in glaciers in the Himalayas.

Soaking up the heat

Diesel fumes, along with smoke from coal burning, cooking fires and the burning of waste, are among the main sources of particulate matter called soot or black carbon. Recent studies suggest that funeral pyres and even the burning of incense at temples are also contributors to the accumulation of soot.

This black carbon rises into the atmosphere and is driven by winds on to the snow or ice in the Himalayas, darkening the surface and in the process reducing reflectivity and causing the surface to absorb more heat.

The International Centre for Integrated Mountain Development (ICIMOD), based In Kathmandu, Nepal, is the only transboundary organisation looking at climate developments across the Hindu Kush-Himalayan region.

According to ICIMOD estimates, black carbon is likely responsible for a large part – around 30% by some calculations – of glacial melt in the region. It says most of the black carbon deposited in the Himalayas and in the southern area of the Tibetan Plateau comes from the plains of India, while black carbon on the eastern and northern parts of the Plateau originates in central China.

Bigger harvests

ICIMOD says that while data is limited, studies suggest black carbon may not only be a factor in hastening the melt of mountain glaciers – it could also substantially alter rainfall patters and affect the behaviour of the monsoon.

While many well-organised environmental NGOs and other groups have formed in India in recent years, the environment – and climate change – does not come high on the political agenda.

A late 2013 study by the World Bank and the International Cryosphere Climate Initiative (ICCI) said that up to a million deaths could be avoided each year in the Himalayan region by cutting back on emissions of black carbon and methane. The study also said that regional yields of crops such as rice and wheat could be significantly improved by reducing black carbon.

“The health of people around the world will improve greatly if we reduce emissions of black carbon and methane”, says Jim Yong Kim, the World Bank president.

“Limiting these emissions will also be an important contributor to the fight against climate change.” – Climate News Network

Climate change ‘helped to end monsoon 4,000 years ago’

February 27, 2014 in Archaeology, Climate, Drought, History, Monsoon, Palaeoclimatology

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A well and bathing platforms from Harappa, brought low when the monsoon weakened Image: Obed Suhail via Wikimedia Commons

A well and bathing platforms from Harappa, brought low when the monsoon weakened
Image: Obed Suhail via Wikimedia Commons

By Tim Radford

Drought appears to have played a significant part in the collapse of a vibrant community in south-west Asia several thousand years ago, British researchers say – with lessons for us today.

LONDON, 27 February – Climate change can seriously damage a civilisation. An “abrupt weakening” of the summer monsoon in north-west India accompanied the decline of the great cities of the Indus valley more than 4,000 years ago, according to new research by British scientists.

They analysed the oxygen isotopes in snail shells preserved in ancient lake sediments to build up a picture of rainfall patterns in prehistory, and found the first direct evidence that sustained drought contributed to the collapse of a great Bronze Age civilisation, they report in the journal Geology.

The Indus or Harappan civilisation – after Harappa, one of the five great ancient settlements of what is now Pakistan and western India – was marked by the world’s first “megacities”, concentrations of population in built-up areas that covered more than 80 hectares.

“They engaged in elaborate crafts, extensive local trade and long-ranging trade with regions as far away as the modern-day Middle East,” said Cameron Petrie of the University of Cambridge. “But by the mid-second millennium BC, all the great urban centres had dramatically reduced in size or been abandoned.”

The finding links the decline of the Indus civilisation to what now seems a much greater scale event: the failure of Early Bronze Age civilisation in Greece and Crete, the weakening of the Old Kingdom in Egypt, and the crumbling of the Akkadian Empire in Mesopotamia.

Common factor

Researchers last year used pollen grain sediments in an old lake bed in Cyprus to build up a picture of sustained environmental decline that accompanied the collapse of the civilisations linked with Mycenae in Greece and Knossos in Crete. In all cases, there must have been a number of factors at work, but common to them all was a pattern of drought.

Without water crops fail, populations fall and concentrations of people must disperse. Archaeological evidence in the north-west Indian sub-continent has told a story of dispersal. Palaeontological evidence from an old lake bed has confirmed the picture of a changing climate.

“We think we now have a really strong indication that a major climate change event occurred in the area where a large number of Indus settlements were situated,” said David Hodell, an earth scientist at Cambridge, and one of the authors.

“Taken with other evidence from Meghalaya in north-east India, Oman and the Arabian Sea, our results provide strong evidence for a widespread weakening of the Indian summer monsoon across large parts of India 4,100 years ago.”

The authors collected shells of the water snail Melanoides tuberculata from the sediments on an ancient lake, Kotla Dahar in Haryana, India. The changes in oxygen isotope ratios over a period of thousands of years told the researchers a story of a deep lake that became a shallower one, as evaporation accelerated and water supplies dwindled, and then all but disappeared, with an abrupt weakening of the monsoons that lasted around 200 years.

Syrian parallel?

Oxygen occurs in two isotopes: water molecules containing the lighter variant evaporate at a predictably faster rate than the heavier version. In a drought, the ratios of the heavier version increase, and this increase is preserved in the calcium carbonate of the snail shells, which can in turn be dated by radiocarbon measurements.

Archaeological evidence suggests that around the time of the 200-year drought, streets that had once been well-maintained started to fill with rubbish, craftsmanship seemed to become less sophisticated, and the locations of settlements changed.

“It is essential to understand the link between human settlement, water resources and landscape in antiquity,” said Dr Petrie. “We hope that this will hold lessons for us as we seek to find means of dealing with climate change in our own and future generations.”

Simultaneously, a French academic has argued that extended drought may have played a role in the crisis in Syria right now. Francesca de Chatel of Radboud University in the Netherlands writes in Middle Eastern Studies that in her opinion the bloodshed and turmoil in Syria is the culmination of 50 years of sustained mismanagement of water and land resources, capped by a severe drought during the years 2006-2010.

She argues “It was not the drought per se, but rather the government’s failure to respond to the ensuing humanitarian crisis that formed one of the triggers of the uprising, feeding a discontent that had long been simmering in rural areas.” – Climate News Network

Offshore wind could calm hurricanes

February 26, 2014 in Climate, Coastal Threats, Energy, Extreme weather, Hurricanes, Technology, USA, Weather Systems, Wind power

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It's smaller, but the same principle applies: Wind energy is dissipated as it crosses a wind farm Image: By Michael via Wikimedia Commons

It’s smaller, but the same principle applies: Wind energy is dissipated as it crosses a wind farm
Image: By Michael via Wikimedia Commons

By Tim Radford

US scientists say that very large wind farms could not only withstand a hurricane: they would also weaken it and so protect coastal communities.

LONDON, 26 February – US engineers have thought of a new way to take the heat out of a hurricane. Fortuitously-placed offshore wind farms could make dramatic reductions in wind speeds and storm surge wave heights.

Hurricanes are capricious consequences of peculiar sea temperature and wind conditions, while wind farms are the outcome of years of thoughtful design and investment, and not an emergency response to a severe weather warning.

But, according to new research in Nature Climate Change, a giant wind farm off the coast of New Orleans in 2005 could have lowered the wind speeds of Hurricane Katrina by between 80 and 98 miles an hour, and decreased the storm surge by 79%.

Katrina was a calamitous event that caught civic, state and federal authorities off-guard, and devastated the city. But an array of 78,000 wind turbines off the coast would, according to Mark Jacobson of Stanford University, and Cristina Archer and Willett Kempton of the University of Delaware, have defused its force dramatically – and turned a lot of hurricane energy into electricity at the same time.

Wind turbines turn in the wind to generate energy. The laws of thermodynamics are inexorable, so a national grid’s gain is the wind’s loss, because wind energy is dissipated as it crosses a wind farm. One turbine literally takes the wind out of the sails of another.

Tempest models

One of the three Nature Climate Change authors, Cristina Archer, last year examined the geometry of a hypothetical wind farm to work out how to place turbines most efficiently to make the best of a gusty day, rather than have one bank of turbines turning furiously while the others barely stir.

But this same translation of wind circulation to electrical circuitry suggested another accidental consequence. Mark Jacobson and his colleagues used sophisticated computer models to test the impact of a hurricane on a wind farm, and since the US has both cruel experience and highly detailed records of hurricane events, he and his Delaware partners decided to model three notorious tempests: Superstorm Sandy, which slammed into New York in 2012 and caused $82 billion damage in three US states, Hurricane Isaac, which hit Louisiana the same year, and Hurricane Katrina in 2005.

“We found that when wind turbines are present, they slow down the outer rotation winds of a hurricane,” Professor Jacobson said. ”This feeds back to decrease wave height, which reduces movement of air toward the centre of the hurricane, increasing the central pressure, which in turn slows down the winds of the entire hurricane and dissipates it faster.”

And Cristina Archer put it more vividly: “The little turbines can fight back the beast,” she said. Her colleague Willett Kempton added: “We always think about hurricanes and wind turbines as incompatible. But we find that, in large arrays, wind turbines have some ability to protect both themselves and coastal communities from the strongest winds.”

Double benefit

The conclusions are based entirely on computer simulations. Real world tests are for the moment unlikely, chiefly because wind farms tend to have dozens or, at the most, hundreds of turbines and the hurricane experiment was based on turbines in their tens of thousands, delivering hundreds of gigawatts.

But Professor Jacobson and Dr Archer tend to think big anyway. They argued in 2012 that four million wind turbines in the world’s windiest places could generate at least half the world’s electricity needs by 2030 without interfering too greatly with global atmospheric circulation.

The tempest-taming qualities of really big wind farms would deliver an added bonus: they could offer protection to vulnerable coastal cities. The costs of wind-farming on such a scale would be huge, but then the losses to coastal cities from flooding and storm damage in a rampant climate change scenario are expected to rise to $100 trillion a year by 2100.

The three authors calculate that the net cost of such projects – after considering all the good things that could come from them – would be “less than today’s fossil fuel electricity generation net cost in these regions and less than the net cost of sea walls used solely to avoid storm damage.”

A sea wall to protect one city might cost anything from $10 billion to $29 billion, and that is all it would do: protect that city. A really big wind farm would offer protection during cyclones, typhoons or hurricanes and generate carbon-free energy all year round. – Climate News Network

Penguins feel climate change’s impacts

February 1, 2014 in Antarctic, Climate, Extreme weather, Marine ecology, Rainfall, South America, Weather, Wildlife

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Adélie penguin chicks chase an adult in the hope of finding food Image: Liam Quinn from Canada via Wikimedia Commons

Adélie penguin chicks chase an adult in the hope of finding food
Image: Liam Quinn from Canada via Wikimedia Commons

By Tim Radford

Scientists have identified climate change as the direct cause of rising mortality among penguin chicks hatched in Argentina.

LONDON, 1 February – Climate change is bad for penguin chicks. If rain doesn’t soak their feathers and kill them with cold, then extremes of heat could finish them off with hyperthermia.

Over a 27-year research project in the world’s largest colony of Magellanic penguins, on the arid Argentine coast, researchers have seen a greater number of deaths directly attributable to climate change.

“We’re going to see years where almost no chicks survive if climate change makes storms bigger and more frequent during vulnerable times of the breeding season”, says Ginger Rebstock, who, with Dee Boersma, reports on the state of penguin survival in the Public Library of Science journal PLOS One.

The two scientists, biologists from the University of Washington, Seattle in the US, believe starvation and weather are going to make life harder for the offspring of the 200,000 pairs of penguins that breed each year at Punta Tombo, on Argentina’s Atlantic coast.

The number of storms during the first two weeks of December – when all the chicks are less than 25 days old and their downy coats are not yet waterproof – has increased between 1983 and 2010.

Every new chick is at hazard: over the span of study, the researchers calculate that 65% of chicks do not survive, 40% of them die by starvation. But climate change has begun to offer new dangers.

A Magellanic chick, still too young to have an adult's waterproofing, in the rain Image: D Boersma/University of Washington

A Magellanic chick, still too young to have an adult’s waterproofing, in the rain
Image: D Boersma/University of Washington

Some years up to half of all chicks die because of the weather. Punta Tombo is historically an arid region. In the last 50 years, the scientists report, rainfall has increased. The number of wet days has increased, the number of consecutive wet days has increased and the level of rainfall during those days has continued to increase.

Air temperatures changed too. The minimum temperatures decreased by up to 3°C and the number of these colder days increased. Storms, too, make it more difficult for foraging parents to gather enough food to feed their chicks.

Sea ice changes

“Starving chicks are more likely to die in a storm”, says Prof Boersma. “There may not be much we can do to mitigate climate change, but steps could be taken to make sure the Earth’s largest colony of Magellanic penguins have enough to eat by creating a marine protected reserve, with regulations on fishing, where penguins forage while raising small chicks.”

Further south, extreme weather is beginning to make life difficult for the Adélie penguins of Ross Island in Antarctica. Amélie Lescroël from the CNRS in France and colleagues report in the same edition of PLOS One that abnormal sea ice conditions reduce access to food.

Antarctic penguins are of course adapted to sea ice: it is their preferred habitat. But they must respond to short and long term changes in ice levels. For 13 years, scientists have monitored the feeding success of the Ross Island colony and observed that the birds could cope in those seasons when there was less sea ice.

But climate change in Antarctica, too, creates new problems for the birds and limits their foraging efficiency.

“Our work shows that Adélie penguins could cope with less sea ice around their summer breeding grounds”, said Dr Lescroël. “However, we also showed that extreme environmental events, such as the calving of giant icebergs, can dramatically modify the relationship between Adélie penguins and sea ice.”

If the frequency of such extreme events increases, then it will become hard to predict how penguin populations will get by, she thinks. – Climate News Network

Atlantic changes are warming Antarctic

January 31, 2014 in Antarctic, Atlantic, Atlantic Multidecadal Oscillation, Climate, El Niño, Ice Loss, Ocean Warming

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Ice covering the Bellingshausen Sea in Antarctica - and feeling the impact of changes in the Atlantic Image: NASA/Michael Studinger via Wikimedia Commons

Ice covering the Bellingshausen Sea in Antarctica – and feeling the impact of changes in the Atlantic
Image: NASA/Michael Studinger via Wikimedia Commons

By Tim Radford

More evidence has emerged that changing climate in one region can have unpredictable effects many thousands of miles away.

LONDON, 31 January – The Antarctic Peninsula is now the strongest-warming region on the planet. Blame that on changes in the faraway North and tropical Atlantic Ocean.

Xichen Li of New York University in the US and colleagues matched sea surface temperature variations in the northern Atlantic over a three-decade period against long-term changes in the Antarctic. They found a clear correlation, they report in Nature.

They also observed that warming Atlantic waters were followed by changes in sea level pressure in the Antarctic’s Amundsen Sea, and these changes also preceded changes in sea ice between the Ross and Amundsen-Bellinghausen-Weddell Sea. Both stretches of water lie many thousands of miles south of the Atlantic.

Correlations are not causes, so the authors then followed up their observational data by experiments with computer models of the global atmosphere. When they simulated a warming of the North Atlantic, the model “changed” the climate in Antarctica.

That Pacific Ocean temperatures can affect Antarctica is no surprise: such things have been linked to the El Niño cycle, a periodic natural pulse of heat in the equatorial Pacific.

Icy paradox

But until this study, no-one had thought to link Antarctica with long-term changes in the North Atlantic,and  in particular, a climatic phenomenon known as the Atlantic multidecadal oscillation, a cycle of natural warming and cooling that can last for 20 to 40 years.

“Our findings reveal a previously unknown – and surprising – force behind climate change that is occurring deep in our southern hemisphere: the Atlantic Ocean”, says Li. “Moreover, the study offers further confirmation that warming in one region can have far-reaching effects in another.”

The Antarctic presents a paradox: the sea ice in the Arctic is declining rapidly; but conditions in the Antarctic don’t seem to have been changing at the same rate or in the same pattern. Concentrations of ice have changed but there seems to be as much sea ice or more, overall.

David Holland of New York University, a co-author, says: “From this study, we are learning just how Antarctic sea ice redistributes itself, and also finding that the underlying mechanisms controlling sea ice are completely distinct from those in the Arctic.” – Climate News Network