Ancient landscapes point to dramatic climate change

Ancient landscapes point to dramatic climate change

Scientists believe Chinese civilisation could have been founded by climate refugees after the collapse of an Inner Mongolian culture over 4,000 years ago.

LONDON, 26 February, 2015 − Chinese and US scientists have uncovered prehistoric evidence of mass migration triggered by climate change.

Something occurred 4,200 years ago – a collapse of the monsoon system, the sapping of the groundwater, the sudden drainage of a lake – that brought a Neolithic culture to an end and left nothing but sandy landscapes in China’s Inner Mongolia region.

Archaeological evidence has revealed the jade carvings that once marked the Hongshan culture, along with evidence of hunting, fishing and even commercial traffic with Mongolian shepherds. And then the artefacts stop.

There is a 600-year period marked by no evidence of human settlement at all. Where there had once been streams, lakes grassland and forest, and a flourishing new Stone Age culture, only shifting sand dunes remained.

Recent origin

Xiaoping Yang, professor in the Institute of Geology and Geophysics at the Chinese Academy of Sciences, Beijing, and research colleagues from China, New Mexico, Hawaii and Texas report in the Proceedings of the National Academy of Sciences that they used a new laboratory technique to show that the northern Chinese deserts were not – as many had thought – millions of years old.

Instead, they are of very recent origin, and the researchers found evidence of dramatic change during human settlement.

In addition, the exploration of artefacts in the region – and the discovery, among other things, of a jade object that might be a dragon − now suggests that Chinese culture and identity may have its origins in the far north, rather than in the Yellow River basin, which has been the archaeologists’ working hypothesis until now.

“This study has far-reaching implications for understanding how human populations respond and adapt to drastic climate change”

If that was so, then one of the world’s great civilisations was founded by climate refugees.

Extraordinary claims require extraordinary evidence. The Beijing team used space-based radar topography measurements to show that the dunes and depressions of the Hunshandake region of northern China had once been home to lakes fed by a system of streams and rivers.

This was then confirmed with fossil evidence of tree pollens and algae that typically float in freshwater lakes.

The scientists built up a timetable of events by dating sediment samples with a technique called optically-stimulated luminescence, which reveals when minerals were last exposed to sunlight.

They started with the proposition that an extraordinary series of droughts occurred in the northern hemisphere around 4,200 years ago, in North Africa, the Middle East and the Mediterranean.

Something similar happened in Hunshandake at around that time. The monsoon rainfall weakened, the lake levels dropped dramatically, and the water table was lowered drastically − and perhaps finally.

The researchers call it a “rapid and catastrophic shift”. And they warn that their research suggests that attempts to reverse the advance of the deserts in the region are likely to have limited success, because the change in the hydrological system is irreversible. Any water that fell there would just trickle away.

Human departure

Such discovery of links between climate and human departure is not isolated. In the last two years, meteorologists and archaeologists have identified climate change as a factor in the collapse of the Bronze Age Mediterranean culture, the implosion of the Assyrian empire at Nineveh in the 7th century BC, and the end of the Indus Valley civilisation 4,000 years ago.

Climate has also been implicated in the advance of the armies of Genghis Khan in the 13th century.

While climate change cannot explain everything about such shifts in ancient history, it is a factor.

But, say the Beijing scientists, “our evidence suggests that Hongshan culture was devastated by combined regional green/desert vegetation shift”, and that the change was intensified and made final by a sudden and final sapping of the groundwater table below the lakes and pastures in the region.

The scientist who used the optically-stimulated luminescence technique, geologist Steven Forman, of Baylor University in Texas, says: “This study has far-reaching implications for understanding how human populations respond and adapt to drastic climate change.” – Climate News Network

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Climate impacts on European farmers’ yields per field

Climate impacts on European farmers’ yields per field

Scientists says changes in temperature and snow or rainfall are key factors in the stagnation of wheat and barley yields across Europe since the early 1990s.

LONDON, 19 February, 2015 – Farmers in Europe have already begun to feel the pinch of climate change as yields of wheat since 1989 have fallen by 2.5% and barley by 3.8% on average across the whole continent.

And two Californian scientists now believe that changes in temperature and snow or rainfall during the last quarter of a century are at least partly to blame.

The pinch may be gentle, but environmental scientists Frances Moore and David Lobell, of Stanford University, believe it is real.

They report in the Proceedings of the National Academy of Sciences that although changes in farming and environmental policies explain much of the stagnation of yields in Europe in the last 25 years, at least 10% of this change could be attributed to climate trends.

Sugarbeet and maize harvests have gone up slightly − and that, too, could be pinned on global warming.

Overall trends

It is no small challenge to find an overall trend to crop yields across a continent that stretches from Scotland to the Black Sea, from northern Norway to Sicily, and over a timescale that embraces floods, droughts, forest fires and heat waves that may or may not have been made worse or more frequent by global warming, but which would have occurred anyway.

The other complication is that, in the same 25 years, the patterns of agricultural subsidy and market demand have also changed.

But the Stanford scientists started with conditions on the farms in the 1980s, when Europe’s farmers were, on average, getting 0.12 more tonnes of wheat and barley per hectare than the year before. Yields per field were rising steadily.

“Agriculture is one of the economic sectors most exposed to climate change impacts”

“If they had continued growing at that rate after 1995, wheat and barley yields would be 30% and 37% higher today, respectively,” they write.

Climate trends could perhaps account for around 10% of the stagnation revealed in the statistics. The remaining change could be put down to economic and political shifts and other factors.

One of these would be that crops had been improving to a point called the biophysical limits: just how much weight of grain could one stalk hold anyway? So some change would be expected, and climate must be a component of that.

To arrive at their conclusion, the two scientists looked at the predictions made for climate change – southern Europe was always expected to become drier, but farmers in moist northern climates could benefit from temperature increases – and the available data, and then applied sophisticated mathematical probability techniques to isolate the possible impact of climate change so far.

Social costs

They have looked at the economic and social challenges of global warming before. Last year, they warned that Europe’s farmers were going to have to adapt to climate change in the 21st century, and Moore and a colleague claimed last month that economists had badly underestimated the economic and social costs of each tonne of carbon added to the levels of CO2 in the atmosphere.

The new research is, they argue, important because “agriculture is one of the economic sectors most exposed to climate change impacts, but few studies have statistically connected long-term changes in temperature and rainfall with yields.

“Doing so in Europe is particularly important because yields of wheat and barley have plateaued since the early 1990s ,and climate change has been suggested as a cause of this stagnation.” – Climate News Network

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Stalagmite links rain reduction to industrial revolution

Stalagmite links rain reduction to industrial revolution

Research shows the explosion of fossil fuel use to power the 19th-century industrial boom began the pattern of lower rainfall affecting the northern tropics. 

LONDON, 17 February, 2015 − Scientists have identified a human-induced cause of climate change. But this time it’s not carbon dioxide that’s the problem − it’s the factory and power station chimney pollutants that began to darken the skies during the industrial revolution.

Analysis of stalagmite samples taken from a cave in Belize, Central America, has revealed that aerosol emissions have led to a reduction of rainfall in the northern tropics during the 20th century.

In effect, the report in Nature Geoscience by lead author Harriet Ridley, of the Department of Earth Sciences at the University of Durham, UK, and international research colleagues invokes the first atmospheric crisis.

Acid rain

Before global warming because of greenhouse gases, and before ozone destruction caused by uncontrolled releases of chlorofluorocarbons, governments and environmentalists alike were concerned about a phenomenon known as acid rain.

So much sulphur and other industrial pollutants entered the atmosphere that raindrops became deliveries of very dilute sulphuric and nitric acid.

The damage to limestone buildings was visible everywhere, and there were concerns – much more difficult to establish – that acid rain was harming the northern European forests.

But even if the massive sulphate discharges of an industrialising world did not seriously damage vegetation, they certainly took a toll on urban human life in terms of respiratory diseases.

Clean-air legislation has reduced the hazard in Europe and North America, but it seems that sulphate aerosols have left their mark.

Researchers in a cave in Belize. Credit: Dr James Baldini/Durham University

Researchers in a cave in Belize.
Image: Dr James Baldini/Durham University

The Durham scientists reconstructed tropic rainfall patterns for the last 450 years from the analysis of stalagmite samples taken from a cave in Belize.

The pattern of precipitation revealed a substantial drying trend from 1850 onwards, and this coincided with a steady rise in sulphate aerosol pollution following the explosion of fossil fuel use that powered the Industrial Revolution.

They also identified nine short-lived drying spells in the northern tropics that followed a series of violent volcanic eruptions in the northern hemisphere. Volcanoes are a natural source of atmospheric sulphur.

Atmospheric pollution

The research confirms earlier suggestions that human atmospheric pollution sufficient to mask the sunlight and cool the upper atmosphere had begun to affect the summer monsoons of Asia, and at the same time stepped up river flow in northern Europe.

The change in radiation strength shifted the tropical rainfall belt, known as the intertropical convergence zone, towards the warmer southern hemisphere, which meant lower levels of precipitation in the northern tropics.

“The research presents strong evidence that industrial sulphate emissions have shifted this important rainfall belt, particularly over the last 100 years,” Dr Ridley says.

“Although warming due to man-made carbon dioxide emissions has been of global importance, the shifting of rain belts due to aerosol emissions is locally critical, as many regions of the world depend on this seasonal rainfall for agriculture.” – Climate News Network

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Arid areas of US face prospect of ‘megadroughts’

Arid areas of US face prospect of ‘megadroughts’

Scientists in the US predict droughts worse than the extreme conditions believed to have played a part in ending a once-flourishing medieval culture.

LONDON, 15 February, 2015The Central Plains and Southwest region of the US face “unprecedented” droughts later this century, according to new research.

While Midwest states have experienced ever more flooding over the last 50 years, the regions already suffering from extremes of aridity are being warned to expect megadroughts worse than any conditions in the last 1,000 years.

Climate scientist Benjamin Cook, of NASA’s Goddard Institute for Space Studies, New York, and colleagues report in a new journal, Science Advances, that they looked at historical evidence, climate projections and ways of calculating soil moisture.

They found that the drought conditions of the future American west will be more severe than the hottest, most arid extended droughts of the 12th and 13th centuries, which are thought to have played a role in ending the once-flourishing Pueblo culture of the American Southwest.

Computer predictions

The growth rings of trees provided the evidence for reconstructions of what climatologists call the warm Medieval period, and the researchers matched the picture from the past with 17 different computer model predictions of the climate later in the 21st century.

The conclusions were ominous: nearly all the models predicted that the Plains and the Southwest would become drier than at any time in the last 1,000 years.

Even though winter rain and snowfall could increase in parts of California – currently in the grip of calamitous drought – in the decades to come, overall there will be lower cold season precipitation and, because of higher temperatures, ever more evaporation and ever more water demand for the surviving vegetation.

The authors conclude: “Ultimately, the consistency of our results suggests an exceptionally high risk of a multidecadal megadrought occurring over the Central Plains and Southwest regions during the late 21st century, a level of aridity exceeding even the persistent megadroughts that characterised the Medieval era.”

“I was honestly surprised at just how dry the future is likely to be”

Co-author Toby Ault, head of the Emergent Climate Risk Lab at Cornell University, warned of future megadroughts only last year. He says: “I was honestly surprised at just how dry the future is likely to be.”

But to the north, in the American Midwest, conditions have begun to change in a different way. Iman Mallakour and Gabriele Villarini, of the Department of Civil and Environmental Engineering at the University of Iowa, collected evidence from 774 stream gauges in 14 states from 1962 to 2011.

Flood events

They report in Nature Climate Change that a third of them had recorded a greater number of flood events, and only one in 10 recorded a decrease.

The pattern of increase extended from North Dakota south to Iowa and Missouri, and east to Illinois, Indiana and Ohio.

The region was hit by economically-disastrous, billion-dollar floods in 1993, 2008, 2011, 2013 and 2014. The researchers wanted to see whether flooding was really on the increase, or whether perception of greater flooding was what they called “an artefact of our relatively short collective memory”.

The result is a confirmation of perceived increase. It was not an artefact.

“It’s not that big floods are getting bigger, but that we have been experiencing a larger number of big floods,” Dr Villarini says. – Climate News Network

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Climate data gives mixed message on storm forecasts

Climate data gives mixed message on storm forecasts

New research suggests that climate change won’t after all lead to more storms − but the bad ones could be even more devastating.

LONDON, 8 February, 2015 − Keep calm and hold on to your hat. The atmosphere will not become increasingly stormy as the planet warms and the climate changes.

The downside is that while the number of storms will probably remain unchanged, and weak storms could even become weaker, new research warns that the strongest storms could become significantly stronger.

For at least three decades, researchers have worked on the assumption that as the average energy of the atmosphere increased with warming, so would the potential for extremes of heat and drought, flood and cyclone, typhoon or hurricane.

Frederic Laliberté, of the University of Toronto in Canada, and atmospheric physicist colleagues don’t exactly disagree: they just took a closer at the way in which some things are likely to change.

Heat engine

They report in the journal Science that they considered the interplay of weather, moisture and temperature around the globe as an atmospheric heat engine – which it is – and compared it to a famous 19th-century theoretical model of energy and output known to engineers, physicists and meteorologists everywhere as the Carnot Cycle.

The engine works like this: air warmed by the sun moves across the ocean and takes up water through evaporation. The warmer the air, the more water it takes up. The air current gets to the Equator and then ascends through the atmosphere, cooling as it rises.

As the air cools, the burden of water condenses and releases heat. When enough heat is released, the air rises even further, pulling more air behind it to produce a thunderstorm.

A more vigorous water cycle could actually take yet more steam out of the atmospheric circulation.
The winds could run out of puff.

So the atmospheric engine’s output is the amount of heat and moisture it distributes between the Equator and the Poles.

“By viewing the atmospheric circulation as a heat engine, we were able to rely on the laws of thermodynamics to analyse how the circulation would change in a simulation of global warming,” Dr Laliberté said. “We used these laws to quantify how the increase in water vapour that would result from global warming would influence the strength of the atmospheric circulation.

To do this, they had to build on climate models, examine climate records for the last 30 years, and simulate the planet’s climate from 1982 to 2098.

Energy budget

They worked out that although the atmosphere is a machine, it isn’t a perfectly efficient one. At least a third of the atmosphere’s energy budget was dedicated simply to evaporating water and then dropping it as rain, and this drain on the overall energy available actually reduced the potential intensity of the winds around the planet, which is why the weather is, quite often, pleasant.

Like all science, the findings will be tested − first by other scientists and then by the planet itself. Time will tell. But the conclusion is that a more vigorous water cycle could actually take yet more steam out of the atmospheric circulation. The winds could run out of puff.

This wouldn’t work smoothly, though. Air masses that didn’t get to the top of the atmosphere would be weakened, but those that did get to the top would be more tempestuous.

“Powerful storms are strengthened at the expense of weaker storms,” Dr Laliberté says. “We believe atmospheric circulation will adapt to this less efficient form of heat transfer and we will see either fewer storms overall, or at least a weakening of the most common, weaker storms,” – Climate News Network

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California is left high and dry by cannabis growers

California is left high and dry by cannabis growers

As California endures its worst drought since records began, illegal marijuana plantations are being blamed for further depleting precious water resources.

MENDOCINO, 4 February, 2015 − Take a flight over the densely forested area in California’s northern coastal region and it’s not hard to spot the marijuana plantations, their bright green plants standing out in clearings in the surrounding vegetation.

But now the big-money cannabis industry is being blamed for adding to water shortage problems caused by a three-year drought that has seriously affected California’s huge agricultural sector.

Although cultivating and using marijuana is illegal under US Federal law, California state law allows marijuana growing – as long as it is for medicinal purposes.

Rules flouted

However, the rules governing who can and cannot grow pot are complex – and openly flouted by thousands of growers, both big and small-time operators.

A report by the California Department of Fish and Wildlife (CDFW) estimates that, in this northern region of the state,  marijuana growing doubled between 2009 and 2012.

Marijuana plants are extremely thirsty, consuming between five and 10 gallons of water per day, depending on the phase of their growing cycle. Officials at the CDFW say that marijuana growers are sucking up precious water resources, exacerbating water shortages and threatening fish in the area’s lakes and streams.

Marijuana growing is particularly prevalent in an area of northern California known as The Emerald Triangle, encompassing Mendocino, Humbolt and Trinity counties. Some estimates say the crop accounts for up to 40% of the region’s economy.

Officials of the CDFW say that the small, well-established marijuana plantations – run by what are described as old time hippies − are not to blame for pumping up excess water.

Illegal marijuana plantations in forest clearings. Image: US Drug Enforcement Agency

Illegal marijuana plantations in forest clearings.
Image: US Drug Enforcement Administration

It is the incomers from outside the area − part of a “green rush” into highly-profitable marijuana growing – that are mainly to blame. These growers are out to make quick profits, and care little about the environment.

Growers of various crops in California are bound by rules stipulating that no more than 10% of the flow of water courses should be diverted for crops, and that such diversions should stop altogether in late summer, when water levels are at their lowest.

The CDFW says the incomers take vast amounts of water in order to harvest their crops as fast as possible. They also use excessive quantities of fertilizer, which leach into water courses, endangering fish stocks and polluting land.

Armed gangs

Fines of up to $8,000 per day are now being imposed for water theft, although monitoring illegal activities is difficult − and, at times, dangerous. Heavily-armed gangs are often involved in the marijuana growing business, and the CDFW has warned that, as the drought continues, conflicts over water resources are likely to increase.

The Emerald Growers Association, a group that represents some of northern California’s marijuana growers, says more regulation is needed to separate the legitimate pot growers from illegal ones.

The drought in California has been going on since 2011 and is described as the worst in the state since records began in the 1850s.

Arguments continue as to whether man-made climate change or natural phenomena are causing the drought.

Although significant amounts of rain last December helped alleviate dry conditions in some parts of the state, experts say more rain is urgently needed to feed watercourses and restock severely depleted aquifers. – Climate News Network

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US must face up to the dark side of climate change

US must face up to the dark side of climate change

As global temperatures rise, scientists warn that more cities in the US face the threat of power blackouts caused by fierce and frequent hurricanes.

LONDON, 29 December, 2014 − Climate change could leave more Americans in the dark as hurricanes become more intense or more frequent.

Researchers in the US have identified 27 cities that are likely to become more vulnerable to blackouts as a result of floods and high winds hitting the power grid.

They report in the journal Climatic Change that they matched evidence from the past – historic hurricane information – with scenarios for future storm behaviour throughout the US as global temperatures rise. And then they looked at those cities most vulnerable.

Big increase

Top of the list were New York, Philadelphia, Jacksonville, Virginia Beach and Hartford, which all could see a big increase in future risk of power cuts.

The cities most likely to keep the lights burning are Memphis, Dallas, Pittsburgh, Atlanta, and Buffalo.

In fact, there is no certainty about how global warming will affect hurricane patterns. As sea surface temperatures rise above 28°C, hurricanes tend to become more likely, and there is evidence that tropical cyclones in the Northern hemisphere are increasingly likely to threaten cities once considered beyond the hazard zone.

But hurricanes are capricious monsters, and how their characteristics will change with warmer atmosphere is still debated. So the scientists looked at a range of possibilities.

Cities already at risk – such as Miami and New Orleans – will remain at risk. But New York and Philadelphia, and even some inland urban areas, could become susceptible to increasing storm activity.

For New York – devastated by Superstorm Sandy in 2012 – and Philadelphia, the probability of the kind of storm previously considered a once-a-century event is likely to increase by 50%. More people would lose power more often, and the worst storms could be substantially more intense.

Future hazards

The point of the research is to make civic authorities more aware of potential future hazards.

“We provide insight into how power systems along the Gulf and Atlantic coasts may be affected by climate changes, including which areas should be most concerned and which ones are unlikely to see substantial change,” said Seth Guikema, a geographer at Johns Hopkins University in Baltimore.

“If I’m mayor of Miami, we know about hurricanes, we know about outages, and our system has been adapted for it. But if I’m mayor of Philadelphia, I might say: ‘Whoa, we need to be doing more about this.’” – Climate News Network

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Education protects best from climate risks

Education protects best from climate risks

Many of us accept that the world is warming but will not necessarily recognise that climate change caused by human activities is responsible. Social scientists say better education is the answer.

LONDON, 24 December, 2014 − Researchers in the US have confirmed the great global warming paradox: people recognise that climate may be changing and that the storms, floods or heat waves they experience are not normal − but whether they attribute the abnormalities to man-made climate change depends on their existing beliefs.

Political party identification, the researchers found, plays a role in these matters. Democrats generally believe in the idea of global warming, Republicans do not.

Aaron McCright, a sociologist at Michigan State University, and colleagues report in Nature Climate Change that they analysed Gallup Poll data from 2012 on the responses of 1,000 people to temperatures in their home states.

The winter of 2012 was the fourth warmest in the US since 1895. Around 80% of US citizens reported that winter temperatures were warmer than usual, and those polled by Gallup also recognised that the conditions were out of the ordinary.

But only 35% believed that the main cause of the abnormally high temperatures was global warming. “Many people had already made up their minds about global warming and this extreme weather was not going to change that,” said Dr McCright.

Mistaken assumption

“There has been a lot of talk among climate scientists, politicians and journalists that warmer winters like this would change people’s minds. The more people are exposed to climate change, the more they’ll be convinced. This study suggests that this is not the case.”

The research confirms a pattern, and others have already hypothesised that humans are not very enthusiastic about dealing with threats that lie some way in the future. The Michigan State researchers conclude that “actual temperature anomalies influence perceived warming but not attribution of such warmer-than-usual winter temperatures to global warming.

“Rather, the latter is influenced more by perceived scientific agreement; beliefs about the current onset, human cause, threat and seriousness of global warming; and political orientation. This is not surprising given the politicisation of climate science and the political polarisation on climate change beliefs in recent years.”

So the message is: personal experience might help spread support for the idea of adaptive measures, but it may not increase support for mitigation policies.

The North American warm winter of 2012 was only one of a string of extremes that indicate a pattern of change: the 2010 Russian heat wave, Superstorm Sandy on the US East Coast in 2012 and Typhoon Haiyan in the Pacific in 2013 were all natural disasters consistent, the researchers say, “with expectations for a warming world.”

Education matters most

Which is why Wolfgang Lutz of the International Institute for Applied Systems Analysis and colleagues argue in the journal Science that although huge sums of money will be spent on engineering adaptations to climate change, the urgent need is for universal education.

The researchers looked at recently-published analyses of disaster data from 167 countries in the last 40 years and found that making people aware of the hazards and their own vulnerability might do more than sea walls, dams, irrigation systems and other protective infrastructure.

For the researchers, knowledge is power. “Our research shows that education is more important than GDP in reducing mortality from natural disasters. We also demonstrated that under rapid development and educational expansion across the globe, disaster fatalities will be reduced,” said Raya Muttarak, one of the co-authors.

“Education directly improves knowledge, the ability to understand and process information, and risk perception. It also indirectly enhances socioeconomic status and social capital. These are qualities and skills useful for surviving and coping with disasters.” – Climate News Network

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Extremes concern as planet gets hotter and colder

Extremes concern as planet gets hotter and colder

Scientists predict that lethal heat waves in Europe, and ice storms and big freezes across the globe, could become regular events if greenhouse gas emissions are not controlled.

LONDON,  December 18, 2014 − Global average temperatures continue to rise, but new research shows that the extremes of heat and cold are rising even faster.

Scientists report that heat waves have got hotter and cold snaps have got colder at a more extreme rate – and that continuing greenhouse gas emissions will mean that, in another two decades, Europe could experience once every two years the sort of lethal heat waves that occurred once in a thousand years.

Scott Robeson, professor of geography at Indiana University Bloomington in the US, and colleagues report in Geophysical Research Letters that they analysed a set of temperature records from 1881 to 2011 and graded them according to how near or far they were from the normal averages of any particular region of the globe.

Temperature anomalies

They found that the temperature anomalies – extremes of heat and cold – increased more than the overall average temperature of the whole planet. They  also found that cold anomalies – unexpected ice storms, blizzards and big freezes − increased more than the warm anomalies until about 30 years ago. Since then, the heat waves have started to outpace the cold snaps.

The study offers a new way to consider the much-debated “pause” in global warming since 1998. It could be that warming continued over most of the planet, but was offset by strong cooling in the winter months in the northern hemisphere.

Professor Robeson says: “There really hasn’t been a pause in global warming. There has been a pause in northern hemisphere winter warming.

“Arguably, these cold extremes and warm extremes are the most important factors for human society”

“Average temperatures don’t tell us everything we need to know about climate change. Arguably, these cold extremes and warm extremes are the most important factors for human society.”

Robeson and his colleagues are not the first to identify the importance of extremes of temperature in the pattern of global averages. Nor is this the first time that UK Met Office scientists – this time led by Nikos Christidis – have forecast more, and more severe, heat waves, not just in Europe but in many regions.

In 2004, Met Office researchers looked at statistics since 1990 and decided that the 2003 European heat wave − estimated to have claimed at least 20,000 lives, and possibly many more − had been made more than twice as likely because of human influence on the climate.

Pattern of warming

In a paper in Nature Climate Change, they look at the pattern of warming between 2003 and 2012. In that period, summers on average warmed by 0.81°C.

This warming means, they say, that heat waves − and extreme heat waves such as the lethal event in 2003 − have become 10 times more likely.

“Extremely warm summers that would occur twice in a century in the early 2000s are now expected to happen twice a decade,” Dr Christidis says.

“Moreover, the chances of heat waves as extreme as seen in 2003 have increased from about one in a thousand to about one in a hundred years, and are projected to occur once every other year by the 2030-40s under continuing greenhouse gas emissions.” – Climate News Network

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Climate change’s threat of space centre invasion

Climate change's threat of space centre invasion

Rising sea levels and repeated storm damage to natural coastal defences pose an increasing threat to the famous Cape Canaveral rocket launch site in Florida.

LONDON, 15 December, 2014 − Climate change has begun to make its mark on one of America’s most iconic sites – the Kennedy Space Centre at Cape Canaveral in Florida.

Within a decade, according to geologists, the combination punch of rising sea levels and increasing wave energy could start to affect operations at the site where, more than five decades ago, astronauts were launched towards a landing on the Moon.

Peter Adams and John Jaeger, of the University of Florida, have since 2009 been studying the dunes and the beach at Cape Canaveral that historically screened the launch site from even the worst tropical storms.

These dunes were levelled in 2008 during Tropical Storm Fay, in 2011 during Hurricane Irene, and again in 2012 during Hurricane Sandy.

Washed away

Storm waves repeatedly covered a stretch of railroad track built by the US space agency NASA during the 1960s. The line is no longer used, and part of it has been removed to make room for a protective man-made dune. NASA’s own prediction in 2010 was that the line could be permanently breached by 2016.

Hurricane Sandy, the superstorm  that brought catastrophic flooding to New York and caused damage along almost all the US Atlantic seaboard, washed away a section of Cape Canaveral shoreline so close to a US Air Force launch pad that the surrounding fence was left near collapse.

“When you put immovable infrastructure right next to a dynamic environment, something has to give”

Coastal erosion is an enduring fact of life, but during the 1960s the Cape seemed a secure site for one of the great 20th-century adventures.

The two geologists, working as partners with NASA and the US Geological Survey, began looking at a problem that seemed to have been getting worse since 2004: chronic erosion of a six-mile stretch between the two launch pads used for the Apollo missions and space shuttle launches.

According to Dr Adams, the slow rise in sea levels and the increased energy of the ocean’s storm waves – both symptoms of global warming – are almost certainly to blame. He said: “Is it affecting NASA’s infrastructure? The answer’s yes.”

Although man-made dunes will protect the site for the immediate future, the space agency has already spoken of a “managed retreat”. And Dr Jaeger  said: “When you put immovable infrastructure right next to a dynamic environment, something has to give.”

Evidence of flooding

As a coastal facility, Cape Canaveral is naturally vulnerable to hurricanes, which tend to lose their energy as they hit the coasts. But University of Iowa scientists report in the Bulletin of the American Meteorological Society that they have found evidence of flooding by tropical cyclones as far inland as Iowa, in the Midwest.

Gabriele Villarini, a civil and environmental engineer, found the evidence in 30 years’ worth of discharge records from more than 3,000 US Geological Survey stream measurement stations.

Between 1981 and 2011, the US was hit by more than 100 tropical cyclones or hurricanes that did their worst damage at the coast, but could also be linked with major flooding far inland.

“Our results indicate that flooding from tropical cyclones affects large areas of the US and the Midwest, as far inland as Illinois, Wisconsin and Michigan,” Villarini said. – Climate News Network

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