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Western US faces worsening wildfires

April 21, 2014 in Drought, Extreme weather, Jet Stream, USA, Wildfires

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Smoke billows from the Las Conchas fire, which burned 150,874 acres in New Mexico in 2011 Image: Jerry Friedman via Wikimedia Creative Commons

Smoke billows from the Las Conchas fire, which burned 150,874 acres in New Mexico in 2011
Image: Jerry Friedman via Wikimedia Creative Commons

By Tim Radford

The US is likely to experience more warm, dry winters in the west and unusually cold ones in the east and south-east, an international research team says.

LONDON, 21 April – Wildfires in the western United States are getting worse. In the last 30 years they have become both bigger and more frequent, according to a new study in Geophysical Research Letters.

Philip Dennison of the University of Utah and colleagues found that the number of wildfires that burned more than 1,000 acres (405 hectares) increased at the rate of seven fires a year between 1984 and 2011, over an area stretching from Nebraska to California. The total area left smouldering each year increased on average by 355 square kilometres.

The trend is linked to climate change and the implication is that it is likely to become more severe in the coming decades.
“We looked at the probability that increases of this magnitude could be random and in each case it was less than 1%,” said Dr Dennison.

The researchers used satellite data to measure areas destroyed, and matched the evidence against seasonal temperatures and rainfall over the same period. Most areas that saw more fires were also likely to have experienced increases in drought during the same time.

That the US west has been hit by severe drought and has been ravaged by wildfire is hardly news. The connection between drought and wildfire is not straightforward: changes in forest management practices, for instance, could explain some of the increase. In some ecosystems, fire is part of the natural cycle of growth, death and regeneration.

Climate-driven impact

But on balance, high temperatures and sustained drought tend to increase the risk of fire, and the Utah study is the first to make a point of looking at the evidence over nine different ecological regions – mountain forests, warm deserts, grasslands.

Last year, researchers found evidence of an historic increase in wildfire in Alaska, an increase also linked to a pattern of regional warming associated with a build-up of carbon dioxide in the atmosphere.

And a second piece of research suggests that the pattern of heat and drought in the west, and winter ice storms in the east of the US, began a long time ago and is likely to continue.

Scientists from Utah, California, Alaska, Ohio, Japan and China report in Nature Communications that an analysis of oxygen isotope ratios in lake sediments and cave deposits across the US and Canada yielded a picture of temperature patterns, and of changes to the jet stream that brings winter weather to the North American continent, over an 8000-year period.

A trend for warm dry winters in the west and fierce extremes of cold in the east of the US seems to have set in about 4000 years ago and may increase as global average temperatures rise.

Reluctant to pay

“A sinuous or curvy jet stream means unusual warmth in the west, drought conditions in part of the west, and abnormally cold winters in the east and south-east,” said Gabriel Bowen of the University of Utah.

Human-caused climate change is reducing the temperature differences between the equator and the poles, with the polar regions becoming warmer. This tends to make the phenomenon of a sinuous jet stream more frequent, or more intense, or both, which means more extremes of weather in winter in the east, and unseasonal drought or warmth in the west.

Although ice storms, drought, wildfires and hurricanes have cost US residents dearly, public attitudes still present a puzzle. Four months after Hurricane Sandy brought unparalleled levels of flooding and destruction to the New York region in October 2012, scientists at Rutgers University in the US conducted a survey of opinion among 875 residents of New Jersey, which saw some of the worst of the devastation.

The scientists report in the journal Risk Analysis that they found strong support for government policies to reduce the likelihood of damage from future hurricanes. A majority agreed that climate change presented a risk to them and their families.

However, only about one in five of those surveyed were prepared to contribute to a fund, or pay increased state sales taxes, or agree to an extra tax on gasoline sales to pay for mitigation. Four out of five were strongly opposed to this idea. – Climate News Network

Warmer UK will face unequal death risk

April 2, 2014 in Extreme weather, Health, Heatwave, Human response, Temperature Increase, United Kingdom, Urban Heat

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Tower Bridge, the gateway to the East End of London which is likely to feel some of the strongest climate impacts Image: Myrabella / Wikimedia Commons / CC-BY-SA-3.0 & GFDL

Tower Bridge, the gateway to the East End of London which is likely to feel some of the strongest climate impacts
Image: Myrabella/Wikimedia Commons/CC-BY-SA-3.0 & GFDL

By Tim Radford

The impacts of climate change will strike unevenly, within countries as well as between them. People in poorer parts of  southern England will probably suffer most from rising heat.

LONDON, 2 April – Even in Britain, an island kingdom in a temperate zone, global warming will take its toll. And the greatest threat could be to the comfortable home counties of southern England which cluster round London.

According to research in Nature Climate Change, an average rise in summer temperatures of 2°C – and 2°C is the limit beyond which the world’s nations have agreed it would be unsafe to go – would mean around 1,550 extra deaths could be expected.

In the most vulnerable districts, the odds of dying increase by 10% for every 1°C rise in temperatures. In parts of northern England (the study was confined to England and Wales) there might be no extra deaths. But in southern England, which is often hit by extended periods of very warm weather, there was a significant rise in risk.

“It’s well known that warm weather can increase the risk of cardiovascular and respiratory deaths, especially in elderly people,” said James Bennett of Imperial College, London. “Climate change is expected to raise average temperatures and increase temperature vulnerability, so we can expect it to have effects on mortality even in countries like the UK with a temperate climate.”

As in all such forecasts, the extra deaths are notional: they are most likely to be in cases where people are already ill, or very old, and it would always be difficult to attribute any one death directly to a more than usually hot summer day. Britain, like France and other European countries, saw a sharp overall rise in mortality in 2003, when summertime temperatures soared and stayed high.

Bucking the trend

The value of such research is to help local clinics and hospitals to prepare for a greater number of emergencies. Between May and September during the decade 2001-2010, a total of 921,000 people died of cardio-respiratory causes, so the number of predicted extra deaths remains a small proportion of the normal toll.

More than half the deaths would be of people aged 85 and over, and almost two thirds would be women. The extra deaths would happen unevenly: half of all mortality would be in 95 out of 376 local authority districts in England and Wales.

The most vulnerable would be those who lived in already deprived boroughs in London such as Hackney and Tower Hamlets in the East End of the capital, and the chances of death would double on very hot days.

“The reasons for the uneven distribution of deaths in warm weather need to be studied”, said Majid Ezzati, a co-author. “We might expect people in areas that tend to be warmer would be more resilient because they adapt by installing air conditioning, for example. The results show that this isn’t the case in England and Wales.” - 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

Heat extremes threaten crop yields

March 21, 2014 in Agriculture, Climate risk, Drought, Extreme weather, Food security, Temperature Increase, Vegetation changes

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An undersized cob from a failed maize crop in Ghana's Upper West Region, which has suffered failed rains and rising temperatures Image: By CIAT (NP Ghana23_lo  Uploaded by mrjohncummings), via Wikimedia Commons

An undersized cob from a failed maize crop in Ghana which has suffered failed rains and rising temperatures
Image: By CIAT (NP Ghana23_lo Uploaded by mrjohncummings), via Wikimedia Commons

By Tim Radford

Yields of several major crops are likely to be seriously affected by rising temperatures, scientists say, with spells of extreme heat posing the greatest risk.

LONDON, 21 March – Rampant climate change driven by ever-rising levels of carbon dioxide in the atmosphere poses a serious threat to world food supply, according to a new study in Environmental Research Letters.

The hazard comes not from high average temperatures, but the likelihood of heat extremes at times when crops are most sensitive to stress. And the message is: those communities that rely on maize as a staple are more at risk than most.

Delphine Derying of the Tyndall Centre for Climate Change Research at the University of East Anglia in the UK and colleagues looked at one of the big puzzles of the coming decades: what will global warming do for crop yields?

It is not a simple question: climate change must mean more evaporation, more precipitation, longer growing seasons, more warmth, and higher levels of the carbon dioxide that plants exploit by photosynthesis (the process they use to convert light into chemical energy), so the consequence ought to be greater yields. But as every farmer knows, what matters most is the timing of all that warmth, rain, and those dry spells in which the harvest can ripen.

Danger in extremes

There is a second consideration. Climate is the sum of all events. Rather than a steady overall rise in daily temperatures, an increasing number of ever-larger regions are predicted to experience ever more intense extremes of heat, and sometimes cold. Plants can be very sensitive to extremes of heat at flowering time: if the thermometer goes up, the pollen becomes increasingly sterile and less seed is likely to be set. So an extended heat wave in the wrong season could be calamitous.

The Tyndall team included the assumption that nothing would be done about climate change – that is, that governments, industry and people would continue with a business-as-usual scenario. They then chose three well-studied and vital crops – spring wheat, maize and soybean – and tested predictions under 72 different climate change scenarios for the rest of this century.

They allowed for the already-established benign effects of carbon dioxide-driven warming, one of which is that plants can make more tissue and at the same time use water more efficiently, and therefore respond more effectively to drought conditions. They also looked for the outcomes in places where yields could be most vulnerable: for example, the North American corn belt.

Emissions cuts essential

What they found was that – if carbon dioxide fertilisation effects are not taken into account – then maize, wheat and soya yields are all likely to fall, in all five top-producing countries for each of these crops.

When they factored in the benefits of more CO2 in the atmosphere, the picture changed. There would be positive impacts on soya and wheat, but not on maize.

There is another proviso: so far, the benefits of extra CO2 have been confirmed in experimental plant laboratories. The experience in the fields 60 years in the future may be rather different. And in any case, these positive impacts could be severely offset by extremes of heat at the moment when the crops were most vulnerable, so overall, harvests remain at risk.

The best answer, the scientists argue, is to attempt to limit climate change. “Climate mitigation policy would help reduce risks of serious negative impacts on maize worldwide and reduce risks of extreme heat stress that threaten global crop production,” says Deryng. – Climate News Network

AAAS: Climate risks irreversible change

March 18, 2014 in AAAS, Child Malnutrition, Climate risk, Coastal Threats, Extreme weather, Flooding, Food security, IPCC, Weather

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By Alex Kirby

In a highly unusual intervention in the debate over climate policy, US scientists say the evidence that the world is warming is as conclusive as that which links smoking and lung cancer.

LONDON, 18 March – The American Association for the Advancement of Science (AAAS) says there is a “small but real” chance that a warming climate will cause sudden and possibly unalterable changes to the planet.

This echoes the words used in its 2007 report by the Intergovernmental Panel on Climate Change (IPCC), which said climate change might bring “abrupt and irreversible” impacts.

A child with kwasiorkor, caused by evere protein deficiency: Child malnutrition may rise by about a fifth Image: Dr Lyle Conrad via Wikimedia Commons

A child with kwashiorkor, caused by evere protein deficiency: Child malnutrition may rise by about a fifth
Image: Dr Lyle Conrad, Centers for Disease Control and Prevention, via Wikimedia Commons

In a report, What We Know, the AAAS makes an infrequent foray into the climate debate. The report’s significance lies not in what it says, which covers familiar ground, but in who is saying it: the world’s largest general scientific body, and one of its most knowledgeable.

The AAAS says: “The evidence is overwhelming: levels of greenhouse gases in the atmosphere are rising. Temperatures are going up. Springs are arriving earlier. Ice sheets are melting. Sea level is rising. The patterns of rainfall and drought are changing. Heat waves are getting worse, as is extreme precipitation. The oceans are acidifying.

“The science linking human activities to climate change is analogous to the science linking smoking to lung and cardiovascular diseases. Physicians, cardiovascular scientists, public health experts and others all agree smoking causes cancer.

Few dissenters

“And this consensus among the health community has convinced most Americans that the health risks from smoking are real. A similar consensus now exists among climate scientists, a consensus that maintains climate change is happening, and human activity is the cause.”

The report’s headline messages are unambiguous. It says climate change is occurring here and now: “Based on well-established evidence, about 97% of climate scientists have concluded that human-caused climate change is happening.

“This agreement is documented not just by a single study, but by a converging stream of evidence over the past two decades from surveys of scientists, content analyses of peer-reviewed studies, and public statements issued by virtually every membership organization of experts in this field.

“We are at risk of pushing our climate system toward abrupt, unpredictable, and potentially irreversible changes with highly damaging impacts…Disturbingly, scientists do not know how much warming is required to trigger such changes to the climate system.

Expensive to delay

“The sooner we act, the lower the risk and cost. And there is much we can do…as emissions continue and warming increases, the risk increases”.

The AAAS says there is scarcely any precedent for the speed at which this is happening: “The rate of climate change now may be as fast as any extended warming period over the past 65 million years, and it is projected to accelerate in the coming decades.”

Historically rare extreme weather like once-in-a-century floods, droughts and heat waves could become almost annual occurrences, it says, and there could be large-scale collapses of the Antarctic and Greenland ice sheets, and of part of the Gulf Stream, loss of the Amazon rain forest, die-off of coral reefs, and mass extinctions.

The authors acknowledge that what the AAAS is doing is unusual: “As scientists, it is not our role to tell people what they should do or must believe about the rising threat of climate change.

“But we consider it to be our responsibility as professionals to ensure, to the best of our ability, that people understand what we know: human-caused climate change is happening…”

More child malnutrition

At the end of March the IPCC, the UN’s voice on climate science, is due to release a summary of the report of its Working Group II, on impacts, adaptation and vulnerability to climate change.

The London daily The Independent, which says it has seen a draft of the report’s final version, says it will spell out a prospect of “enormous strain, forcing mass migration, especially in Asia, and increasing the risk of violent conflict.”

The newspaper says the report predicts that climate change “will reduce median crop yields by 2% per decade for the rest of the century”, against a backdrop of rising demand set to increase by 14% per decade until 2050. “This will in turn push up malnutrition in children by about a fifth”, it adds.

Other predictions in the draft, The Independent says, include possible global aggregate economic losses of between 0.2 and 2.0%; more competition for fresh water; and by 2100 hundreds of millions of people affected by coastal flooding and displaced by land loss, mainly in Asia. – 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

 

Europe’s flood risk may double by 2050

March 2, 2014 in Europe, European Union, Extreme weather, Flooding, Weather Systems

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Floods submerge St Mark's Square in Venice: The prospect is for worse to come Image: Wolfgang Moroder via Wikimedia Commons

Floods submerge St Mark’s Square in Venice: The prospect is for worse to come
Image: Wolfgang Moroder via Wikimedia Commons

By Tim Radford

As much of Europe recovers from the severest winter in several centuries, scientists say average annual flood losses could be almost five times greater by mid-century.

LONDON, 2 March – The catastrophic floods that soaked Europe last summer and the United Kingdom this winter are part of the pattern of things to come. According to a new study of flood risk in Nature Climate Change annual average losses from extreme floods in Europe could increase fivefold by 2050. And the frequency of destructive floods could almost double in that period.

About two thirds of the losses to come could be explained by socio-economic growth, according to a team led by Brenden Jongman of the University of Amsterdam in the Netherlands and Stefan Hochrainer-Stigler of theInternational Institute for Applied Systems Analysis in Austria.

That is because more development and investment means there is more at risk from any flooding. But the other third of the increase will be delivered by climate change, and a shift in rainfall patterns in Europe.

From 2000 to 2012, floods in European Union countries averaged €4.9 billion (US $6.8 bn) a year in losses. In the floods of June 2013, losses tipped €12 bn (US $16.6 bn) in nine countries of Central and Eastern Europe. The annual average losses could increase to €23.5 bn (US $32.4 bn) by 2050.

Unprecedented floods like those of 2013 occur on average once every 16 years now. By 2050, the probability will have increased to once every 10 years.

Floods widespread

The team looked at monthly peak river discharges in more than 1,000 river sub-basins to begin making their estimates: they also matched these peak flows with atmospheric circulation patterns. The point of the study was to deliver more accurate information.

“We brought together expertise from the fields of hydrology, economics, mathematics and climate change adaptation, allowing us for the first time to comprehensively assess continental flood risk and compare the different adaptation options,” said Brenden Jongman.

And Dr Hochrainer-Stigler said the new study for the first time accounted for the correlation between floods in different countries. Risk-assessment models tended to consider river basins as independent entities. “But in actuality, river flows across Europe are closely correlated, rising and falling in response to large-scale atmospheric patterns that bring rains and dry spells to large regions.”

All of this points to greater strains on the pan-European Solidarity Fund that finances recovery from disaster within the European Union. “If the rivers are flooding in Central Europe, they are also likely to be flooding in eastern European regions,” he said. – 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

Rising sea levels threaten Los Angeles

February 22, 2014 in Drought, Extreme weather, Sea level rise, Temperature Increase, USA

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Residents of the Cabrillo Marine Aquarium, one of the Los Angeles buildings at risk from sea level rise Image: By Jllm06 via Wikimedia Commons

Residents of the Cabrillo Marine Aquarium, one of the Los Angeles buildings at risk from sea level rise
Image: By Jllm06 via Wikimedia Commons

By Tim Radford

As much of California and the western US endures a severe drought, the city of Los Angeles is at increasing risk from rising sea levels, researchers say.

LONDON, 22 February – Los Angeles, City of the Angels in southern California, sits on a flat shelf of the Pacific coast of America, with a view of the sea. And if climate scientists are right, it could soon have an even closer view of the sea.

The city of more than 12 million people occupies 12,000 square kilometres of land, much of it no more than three metres above sea level. By 2050, rising sea levels could pose a threat to the infrastructure, museums and historic buildings of this great capital of entertainment, education, business, tourism and international trade, according to a new study by the University of Southern California.

“Some low-lying areas within the city’s jurisdiction, such as Venice Beach and some areas of Wilmington and San Pedro, are already vulnerable to flooding”, says Phyllis Grifman, lead author of the report, commissioned by the city and the USC Sea Grant Program.

“Identifying where flooding is already observed during periods of storms and high tides, and analyzing other areas where flooding is projected, are key elements to effective planning for the future.”

The city has already started to prepare for climate change: in June last year it published a report from the University of California Los Angeles on the pattern of snow fall and spring melt over recent decades and the ominous message for winter sports and summer water levels.

Double bind

Climate scientists expect the south-west of the US to become more arid as the century advances, and California has been in the grip of recent, unprecedented drought. But as glaciers melt and retreat, and the oceans warm and expand, the City of the Angels could find itself between the devil and the deep blue sea.

Sea levels are expected to rise somewhere between 0.6 metres and 1.7 metres by the close of the century. Peak tides and storm surges already present problems: as sea levels rise, these will become more damaging.

The drains that carry off its storm water and sewage, and deliver clean water from the mountains, could all be at risk from marine incursion. Floods and erosion could wear away the coast roads, and many museums and historic buildings, including the Cabrillo Marine Aquarium, could face damage. In 2012, Los Angeles attracted 41 million tourists who accounted for a total spending of more than $16 billion.

Some coastal communities, the report says “are home to highly vulnerable populations” already struggling with low incomes, linguistic isolation, older housing stock and lower education levels.

And a serious storm – the once-in-a-decade storm – could exact financial losses of $410 million if sea levels rise by half a metre. If they rise by about one and a half metres, the economic costs could tip more than $700 million. – Climate News Network

If it walks like a duck, it probably is climate change

February 17, 2014 in Climate deniers, Climate finance, Extreme weather, Flooding, Journalism, United Kingdom

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The morning after the storm: Aberystwyth in west Wales has borne the brunt this turbulent winter Image: Ian Capper via Wikimedia Commons

The morning after the storm: Aberystwyth in west Wales has borne the brunt this turbulent winter
Image: Ian Capper via Wikimedia Commons

By Phil Rothwell

As debate rages over the part climate change may be playing in Britain’s wet and stormy winter, one of the UK’s foremost experts on flood defence says we need to acknowledge reality – fast.

LONDON, 17 February -  We are in danger of losing sight of some glaringly obvious truths about this exceptionally wet and stormy winter which much of the United Kingdom is enduring:

  • Scientists should acknowledge that the current record-breaking weather, in the UK and globally, is being caused by a changing climate
  • We don’t need party political bickering over flood funding, we need the right budget guaranteed for the future and agreed through political consensus
  • We need a land use policy that reduces reliance on expensive flood engineering and moves toward natural catchment management, flood-friendly farming, and village, town and city location and design that reduces risk, not increases it
  • We need a media and political framework that consigns climate change scepticism to the spike and the cutting room floor.

After the wettest and stormiest period in our history and following 2012, a year when we had both the most severe drought and wettest winter on record up until then, the almost complete failure of those in authority to acknowledge anything other than a faint link to climate change is beyond credibility and fundamentally and fatally damages a logical response.

Such a politically motivated head-in-the-sand attitude is severely damaging to any long-term approach to managing such events, let alone their cause.  As I write this President Obama is visiting California to see the impact of the most testing drought in its history, New York is in the grip of deep snow and ice, and the Philippines once again see major flooding. The Somerset Levels and the floods in the Thames Valley are just a pimple on the surface of the world’s problems. But they need a bit more than a knee-jerk political gesture.

“Over a million properties in Britain’s major conurbations have not flooded this winter because of action over the last few years to protect them”

In the 2007 floods in the UK 10 times as many properties were affected, mainly in urban areas in the north. The limited and largely rural impacts of the current winter, appalling for a few,  are in fact testimony to a successful flood risk management strategy.

Diverting resources to towns and cities, increasing flood protection to often ill-judged development, has proved a major success for the Environment Agency and the policy driver of investment which is targeted where most people live. Over a million properties in Britain’s major conurbations have not flooded this winter because of action over the last few years to protect them.

Many of the houses that have flooded are in rural locations in a flood plain best used to accommodate floods and relieve pressure downstream, thereby reducing even more major losses. We should be congratulating ourselves for a policy that is clearly working, protecting the most populated areas and using the sparsely-populated countryside for flood storage and mitigation.

Of course, whilst such a policy makes economic sense, in rural, social, personal and financial terms it can be a disaster. People are still affected, villages isolated, farmers managing reservoirs not wet meadows. This brings nothing but misery.

But the answer does not lie in more and bigger defences, or massive pumps. We should reforest the uplands, use different farming methods on upper catchment slopes, dam more upstream rivers and streams, create wet storage areas, end development in flood plains, and where there’s redevelopment do it in a way that absorbs and manages water through urban drainage systems and flood-sensitive design.

“Climate change is a generation-defining issue. We cannot afford party politics and the political short-termism of budget planning”

Far away from the knee-jerk throw-money-at-the-problem response in government, there is a truly sustainable approach to both floods and their causes. Combining national land use policy for climate change mitigation with better town and city protection and design is a valuable way forward, replacing high engineering costs with a flood-friendly approach to land management. But it’s not on the political agenda.

Instead we get a feast and famine approach to flood funding. Budget cuts are made in the hope that there will be no flood in the next few years. It happened after 1953, 1998, 2007, and now again in 2014. Cut the budgets until there is a flood and then restore them in the face of public and press criticism.

A decade ago a major Government study into climate change and flood risk, the Foresight Report, recommended a budget of £1 billion per annum, rising with inflation to keep pace with climate risk. The Pitt report in 2007 confirmed this scale of investment need. No Government has come close to matching these proposals, and the consequences become increasingly clear.

Climate change is a generation-defining issue. We cannot afford party politics and the political short-termism of budget planning to dictate a nation’s response to a threat of such scale. We certainly can do without Ministers so climate-sceptic that they delete any references to climate change in their briefs, or seek to blame the Environment Agency for flooding rural areas when that is the inevitable consequence of Government flood management policy.

We need realism about solutions. Most drainage engineers will tell you that dredging the Somerset rivers will make little impact on flooding, at most reducing the length of major floods by a few days.

“Scientists need to grasp the nettle, abandoning their reluctance to ascribe any one event to climate change”

Ironically the rivers would have been dredged last year if, as Government policy requires, the local authorities could have found funds to match those offered by the Environment Agency at the time. Increasingly the authorities are being given greater responsibility for flood management – at a time when their funding is being cut and they cannot find the cash.

What we really need is for the major political parties to meet together and agree a 30-year approach to funding, governance and land use policy in the face of the greatest threat to our lives and our environment ever. You never know. It might look like joined-up policy in the face of high risk, and restore some credibility to the political process.

Scientists, too, need to grasp the nettle and urge the need for long-term planning, abandoning their reluctance to ascribe any one event to climate change. The media should take a responsible science-driven approach and not feed the fire of misplaced scepticism or politically motivated ignorance.

The views peddled by eloquent sceptics such as Nigel Lawson have no place in a rational discussion. Such an approach is akin to denying there is any link between smoking and cancer, or obesity and heart disease. There is no place in a rational government for climate change denial.

The division in the country is fed by political uncertainty. The nation is under threat – and those charged with governing it, or in opposition, need to have that branded on their foreheads so they are forced to confront the reality every time they look in the mirror. – Climate News Network

Phil Rothwell was until December 2013 the Head of Flood Risk Policy at the UK Environment Agency.