Bronze Age lost its cutting edge before climate crisis

Bronze Age lost its cutting edge before climate crisis

Archaeologists claim to have unearthed evidence in Ireland that it was the rising power of iron, not climate change, that brought about the collapse of many ancient civilizations.

LONDON, 23 November, 2014 − Climate change – so often and so recently coupled with the decline of early civilizations in the Near East, the Indus Valley and the Mediterranean – may not have ushered in the collapse of the late Bronze Age after all.

A new study suggests that Bronze Age cultures everywhere collapsed not because of sustained drought or flooding, but because of technological change. The gradual spread of iron foundries and smithies, they say, undermined the economic strengths of those centres with monopolies on the production of, and trade in, copper and tin − the elements in the alloy bronze.

Ian Armit, an archaeologist at the University of Bradford in the UK, and colleagues base their argument on careful studies of ancient climate, using a combination of pollen data and other evidence, plus 2,000 precision-dated archaeological finds from Ireland, from between 1200 BC and 400 AD. This evidence tells a different, but equally familiar, story.

Went wrong

They report in the Proceedings of the National Academy of Sciences that although there was indeed a climate crisis around 750 BC – an event linked to the end of the cultures associated with Knossos in Crete and Mycenae in the Peloponnese – things had started to go wrong two generations or more before.

There had been a clear peak in human activity between 1050 and 900BC, followed by a steady decline and then a rapid fall between 800 AD and 750BC. Since copper was mined in Ireland – and alloyed with tin from Britain to make bronze – the Celtic populations of the place and time enjoyed high socio-economic status and power.

“The impact of climate change on humans is a huge concern today as we monitor rising temperatures”

They were involved in international trade, and at the heart of a global culture. Bronze, both literally and metaphorically, gave the Irish of the time a cutting edge. Such power and status started to evaporate with the advance of iron smithies. Copper and tin are relatively rare metals, but iron is found almost everywhere.

“Our evidence shows definitively that the population decline in this period cannot have been caused by climate change,” Professor Armit concludes.

But he says that the switch to increasingly rainier conditions in Ireland in 750 BC would have had its own impact. “It is likely that poor climatic conditions would have affected farming. This would have been particularly difficult for vulnerable communities, preventing population recovery for several centuries.”

Archaeology is a combative science: the evidence is preserved only precariously and a new discovery can, and often does, change the picture.

Contributing factor

Written records are fragmentary, interpretations open to dispute, and artefacts are often difficult to date. So reconstructions of the distant past are always tentative, and other groups have been careful to “link” or “associate” climate change with historical conflict. Climate would be a contributing factor, not necessarily a prime cause.

But the British scientists argue that, on the evidence from Ireland, a global bronze age civilization was coming to an end for reasons that were ahead of, and independent of, drought or flood, heat waves or sustained cold.

Professor Armit says: “The impact of climate change on humans is a huge concern today as we monitor rising temperatures globally.

“Often, in examining the past, we are inclined to link evidence of climate change with evidence of population change. Actually, if you have high-quality data and apply modern analytical techniques, you get a much clearer picture and start to see the real complexity of human/environment relationships in the past.” – Climate News Network

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Green Revolution trebles human burden on planet

Green Revolution trebles human burden on planet

American researchers say seasonal swings in temperatures and CO2 levels are evidence of how agricultural advances and the population explosion have tilted nature’s balance.

LONDON, 22 November, 2014 – Humans are changing not just climate overall, but also the difference between seasons in any given year.

Researchers in the US believe they now know why global warming has begun to announce itself both in annual rises in temperature and in the seasonal records of carbon dioxide in the northern hemisphere − the same seasonal variation in atmospheric chemistry that also contains within it the signature of the Green Revolution and the 20th-century population explosion.

And it’s all because the natural swing from high carbon dioxide levels to low each year has become more dramatic in the last 50 years.

Each year, in the northern hemisphere growing season, the CO2 levels drop as plants grow and soak up the atmospheric carbon.

Inexorable pattern

Later in the year, as leaves fall, crops are harvested and consumed, and soil is freshly tilled, most of that CO2 gets back into the atmosphere. It’s an inexorable pattern that follows the seasons.

Systematic measurements of CO2 levels began in 1958, and they show that swings within each year from high to low, and back again, have increased in amplitude by 50%, and go on increasing by 0.3% every year.

Two groups of researchers report that they concentrated on the northern hemisphere because that’s the part of the globe where most of the continental landmass, most of the vegetation and the greatest part of the human population is concentrated.

And both groups identified the cause of the widening CO2 swing as being as mix of steadily higher temperatures and the Green Revolution – the dramatic advance in agricultural productivity that fuelled the trebling of the human burden of the planet in less than a human lifetime.

“Changes in the way we manage the land can literally alter the breathing of the biosphere”

Josh Gray, research assistant professor in the Department of Earth and Environment at Boston University, US, reports with colleagues in Nature journal that they have gone one better by identifying the crop that makes the biggest difference: maize, or corn.

Together, the world harvest of maize, wheat, rice and soybean grew by 240% between 1961 and 2008, increasing the uptake of carbon during that time by 330 million tonnes.

Maize, grown ever-more intensively in the mid-western US and in China, is responsible for two-thirds of this change, the researchers calculate. Dr Gray calls the super-productive croplands “ecosystems on steroids”.

Carbon cycle

Ning Zeng, professor in the Department of Atmospheric and Oceanic Science at the University of Maryland, US, and lead author of the other Nature paper, reports that he and colleagues devised a new model of the terrestrial carbon cycle to explore the increase in seasonal CO2 swings, and the role of the Green Revolution in these swings.

There are several reasons for the increasing swings: average temperatures have started to rise; there is the natural “fertilization” effect of carbon dioxide, as some plants respond well to higher levels; and as the Arctic regions have thawed, more growing land is available − and vegetation has been marching north.

But a fourth reason is that farmers are now producing more yield from the same land, and the same crops. Between 1961 and 2010, the area of land planted with the world’s great crops grew by 20%, but – with improved strains, better fertilizers, and more irrigation − yield grew threefold. So more CO2 was taken up each year, and more released.

“What we are seeing is the effect of the Green Revolution on Earth’s metabolism,” said Professor Zeng. “Changes in the way we manage the land can literally alter the breathing of the biosphere.” – Climate News Network

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Saving forests not enough to stop carbon imbalance

Saving forests not enough to stop carbon imbalance

Creeping expansion of croplands into areas not previously covered with trees could undermine attempts by forest conservation schemes to address the problem of “carbon leakage” into the atmosphere.

LONDON, 21 November, 2014 − Foresters may be guardians of the planet, but they may need to think about more than just the forests to reduce the threats from climate change.

New research suggests that a policy that protects the planet’s forests from fire and the chainsaw must also deliver new ways of stopping the spread of agriculture into other habitats.

The trick − according to a report by Alexander Popp, a senior researcher at the Potsdam Institute for Climate Impact Research, Germany, and colleagues − is to be sure to reduce carbon emissions, rather than just displace them.

The researchers argue in the journal Nature Climate Change that while forest protection schemes could, by 2100, prevent 77 billion tonnes of carbon dioxide from escaping into the atmosphere, the same policies could trigger cropland expansion into areas that were not forested.

This, in turn, could release 96 billion tonnes of CO2 over the same timescale. The researchers call this “carbon leakage”.

Changes in land use

That is because around a tenth of emissions of greenhouse gases (GHGs) arise from changes in land use, and the worst of these changes − in terms of GHG releases − is from tropical forest to agricultural cropland.

So any forest policy focusing on saving emissions must also embrace strategies for using existing farmland more efficiently and productively.

Greenhouse gas emissions from fossil fuel combustion provide the chief cause for alarm about climate change, and a switch to renewable sources such as wind, hydro and solar power remains an important part of potential strategies to reduce the hazards of global warming.

“A central challenge is the avoidance of international carbon leakage if forest conservation is not implemented globally”

But, in a whole range of ways, agriculture is responsible for about 25% of all emissions, and in a world certain to reach a population of nine billion this century – and possibly 11 billion − the demands and the impacts of agriculture are likely to increase.

The Potsdam scientists warn: “A central challenge is the avoidance of international carbon leakage if forest conservation is not implemented globally.”

But, they add, even global forest conservation schemes will fail to contain such leakage if croplands expand into areas that may not be forested, and are not protected from development in some way.

Overall, in recent decades, the planet’s lands have soaked up more carbon than they have released. Plants take up CO2 from the atmosphere, and although some of them are harvested, and others are burned or decomposed, a proportion of this sequestered carbon stays in the soil.

Woodland, heath, marsh, savannah and even mature meadow and grazing lands have reached some sort of equilibrium: they remain as carbon sinks.

Disturbed equilibrium

But change, in the form of a farmer’s plough, disturbs this equilibrium. Between 1990 and 2010, say the researchers, 12% of all emissions came from changes in land use and changes in the vegetation that covered the land.

So the Potsdam researchers took a hard look at a UN-proposed strategy called REDD –Reduced Emissions from Deforestation and Degradation – which is likely to remain an important part of all future climate treaty negotiations. The conclusion: it is not enough just to preserve forests alone; nations have to look at the bigger picture too.

“The results show that the largest benefits for climate change mitigation could be achieved by a full participation of all countries in a forest conservation scheme and the inclusion of other land types with high carbon content, such as wet savannahs,” Dr Popp says.

“While protecting forests to abate climate change is definitely worthwhile, our results illustrate for the first time that forest protection policies alone will not be enough.” – Climate News Network

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Fall of ancient civilization offers climate warning

Fall of ancient civilization offers climate warning

Prolonged drought – a familiar climate-related issue in the modern world – is believed by scholars to have been a key factor in the implosion of the powerful Assyrian empire 2,700 years ago.

LONDON, 19 November, 2014 − Two scholars have a new explanation for the collapse of one of the great Bronze Age civilizations. The Assyrian empire of the 7th century BC – based in Nineveh, in what is now northern Iraq – may have collapsed at least in part because of a population explosion and climate change in the form of sustained drought.

And, they point out, there are lessons in ancient history for the modern world as well.

Adam Schneider, an anthropologist at the University of California, San Diego, and Selim Adali, of the Research Centre for Anatolian Civilizations at Koç University in Istanbul, Turkey, put forward their proposal in the journal Climatic Change.

They say that demographic and climatic factors played an indirect but significant role in the collapse of a civilization chronicled not just in clay tablets and archaeological marvels but in the Hebrew scriptures and the Christian Old Testament.

Historic links

The climate change theory of history is now well established. In the last two years, researchers have linked both the dissolution of the Minoan empire in the ancient Mediterranean and the collapse of Levantine civilizations of the near East and the Harappan civilization of the Indus Valley to sustained drought.

Others have identified seasons of plentiful rainfall as the impetus for the conquest of Russia, China and Persia by the Mongol horsemen of Genghis Khan.

The connections with modern conflict, too, have been made before. In 21 studies of upheaval and conflict in modern societies, researchers have found clear links with rises in temperatures.

And just days after the Assyrian study was published in Climatic Change, research in the Proceedings of the National Academy of Sciences identified a link between temperature and rainfall anomalies in sub-Saharan Africa and violence in the region during the last 30 years.

“Hindsight . . . allows us to piece together from the past what can go wrong if we choose not to enact policies that promote longer-term sustainability”

Schneider and Adali looked through what climate scientists call “proxy evidence” of rainfall patterns in the Tigris Valley of northern Iraq more than two and a half millennia ago.

They considered the evidence of lake sediments and confirmed that many parts of the region experienced a “short but widespread dry phase” during the mid-to-late 7th century BC.

They also unearthed written evidence from 666 BC that welcomed “copious rains, huge floods, a fine rate of exchange…” to mark a new accession to the throne. But by 657 BC, another letter stated that “this year’s rains were diminished and no harvest was reaped”.

In fact, Assyrian engineers had established an impressive series of canals, waterways, cisterns and reservoirs to conserve water, and archaeological finds reveal that the imperial farmers grew barley and wheat, grapes, cucumbers, pomegranates, flax and cotton among many other crops.

But demand, too, was on the increase. The empire of built by Sennacherib, a king identified in biblical chronicles, had ambitions for the local populations. In at least 20 known acts of mass deportation, half a million people were resettled in the heartland.

Nineveh grew fivefold in area, and the population growth, the scientists think, placed significant strains on the immediate supplies of food in the region.

Conflict and insurrection

Within five years of the 657 BC drought, the Assyrian economy was struggling, and conflict and insurrection had broken out. By 609 BC, a remarkable civilization had been destroyed.

A multi-year drought, the researchers argue, “would have placed serious stress on the agricultural economy of the Assyrian state and, by extension, upon the imperial political system”.

They see parallels with today, as the fate of the Assyrian empire offers lessons for modern society about the hazards of valuing short-term economic growth over long-term security and sustainability.

“The Assyrians can be ‘excused’ to some extent,” they conclude, “for focusing on short-term economic or political goals that increased their risk of being negatively impacted by climate change, given their technological capacity and their level of scientific understanding about how the natural world works.

“We, however, have no such excuses, and we also possess the additional benefit of hindsight, which allows us to piece together from the past what can go wrong if we choose not to enact policies that promote longer-term sustainability.” – Climate News Network

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Diet’s effects on emissions give food for thought

Diet's effects on emissions give food for thought

American researchers confirm that a shift to vegetarian, Mediterranean or fish-based diets would cut greenhouse gases, conserve forests and savannah, and have a big impact on obesity-linked health problems.

LONDON, 14 November, 2014 − The worldwide trend towards a Western-style diet rich in meat and dairy produce will lead to an 80% increase in greenhouse gas emissions (GHGs) from agriculture.

And since agriculture already accounts for 25% of all emissions, two US scientists argue in Nature journal that a shift away from the trend towards steak, sausage, fried potatoes and rich cream puddings offers tomorrow’s world three palpable rewards.

  • Greenhouse gas emissions would be reduced.
  • There would be less pressure to clear forests and savannah for farmland, so biodiversity would be conserved.
  • There would be lower rates of disease linked with obesity and cardiovascular hazard.

“The implementation of dietary solutions to the tightly-linked diet-environment-health trilemma is a global challenge, and opportunity, of great environmental and public health importance,” the report’s authors say.

For example, GHGs from beef or lamb per gram of protein are about 250 times those from a serving of peas or beans.

Rise in diabetes

And in China, the shift from traditional cuisine towards a Western-style diet rich in refined sugars, refined oils, meat and processed foods led to the incidence of type II diabetes rising from less than 1% in 1980 to 10% in 2008.

To put this greener, more sustainable world on the scientific menu, David Tilman, professor of ecology at the University of Minnesota, and Michael Clark, graduate science student at the Bren School of Environmental Science and Management, University of California Santa Barbara, simply looked at the already published evidence.

They identified 120 separate analyses of the GHGs from the entire life cycle of crop, livestock, fishery and aquaculture, all the way to the farm gate.

These analyses embraced a total of 550 studies, involving 82 types of food plant and animal products, and from all this they were able to calculate the diet-related emissions per gram of protein, per kilocalorie and per serving.

To confirm the connection between diet and health, they looked again at 18 studies based on eight long-term population studies that incorporated 10 million person-years of observation. They used 50 years of data about the dietary habits and trends in 100 of the world’s most populous nations to see the way food consumption patterns were changing.

“Dietary changes that can add about a decade to our lives can also prevent environmental damage”

And they confirmed something that nutritionists, health chiefs and medical advisers have been saying for decades: that a shift to vegetarian, traditional Mediterranean or fish-based diets could only be good.

“We showed that the same dietary changes that can add about a decade to our lives can also prevent massive environmental damage,” Professor Tilman said.

“In particular, if the world were to adopt variations on three common diets, health would be greatly increased at the same time global GHGs were reduced by an amount equal to the current GHGs of all cars, trucks, planes, trains and ships.

“In addition, this dietary shift would prevent the destruction of an area of tropical forests and savannahs of an area half as large as the United States.”

Such a shift away from the calorie-rich Western omnivore diet could reduce the incidence of type II diabetes – a condition notoriously linked to diet and obesity − by about 25%, cancer by about 10%, and death from heart disease by about 25%.

The close link between meat production and GHGs has been reported before.  Researchers have also stressed the environmental value of a diet rich in grains and legumes. rather than meat and dairy.

Not everybody will agree with the detail of their analysis. Other scientists have argued that − in the US, at least − healthy diet recommendations may not make a big difference to GHGs, or might even lead to an increase in them.

Acidic oceans

And because the authors specifically identify trawling for fish as wasteful, destructive and costly in emissions, and because ocean waters are becoming more acidic because of GHG emissions, a planetary switch to a pescatarian or fish and seafood diet is likely to be problematic.

But the two scientists nevertheless are clear on the main point. GHGs are, they say, “highly dependent on diet”.

Between 2009 and 2050, the global population will increase by 36%. People will also become better off, and their appetites and demands will grow. “When combined with a projected increase in per capita emissions from income-dependent global dietary shifts,” they say, “the net effect is an estimated 80% increase in global greenhouse gas emissions from food production.”

This 80% would represent 1. 8 billion tonnes per year of carbon dioxide or its equivalent − which was the total emissions from all forms of global transport in 2010.

“In contrast,” they say, “there would be no net increase in food production emissions if, by 2050, the global diet had become the average of the Mediterranean, pescatarian and vegetarian diets.” – Climate News Network

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World’s wetlands play key role as carbon sinks

World’s wetlands play key role as carbon sinks

Areas of wetlands drained for human habitation and agriculture have been identified by scientists in California as sources of carbon dioxide being released into the atmosphere.

LONDON, 2 November, 2014 − Researchers in the US propose yet another way to reduce greenhouse gas emissions, and at the same time prevent soil subsidence − by preserving and even restoring the world’s wetlands.

Jaclyn Hatala Matthes, a geographer at Dartmouth College in New Hampshire, US, reports in the journal Global Change Biology that she and colleagues from Californian universities measured carbon dioxide and methane from a pasture, a cornfield and a flooded rice paddy, all in the Sacramento-San Joaquin delta in California, which was drained more than a century ago and was settled for agriculture and human habitation.

The researchers found that the drained areas of land were carbon sources − that is, they released carbon dioxide into the atmosphere and added to the greenhouse effect. The flooded region, conversely, turned out to be a carbon sink that took more carbon from the atmosphere than it released.

They also found that the region is literally going down in the world, as soil subsidence rates are almost the highest on the planet.

Short-lived

The picture wasn’t quite perfect: the soggy soils also released methane, which is a greenhouse gas that, molecule for molecule, is 20 times more potent than carbon dioxide. It occurs in much lower concentrations, and is short-lived, staying in the atmosphere for years rather than tens of years. But it does add to global warming.

“However, we do expect that the methane emissions will stabilise over time,” Dr Matthes says. “We’ve seen that emissions tend to increase over the first few years, and that this increase is correlated with an increase in wetland plant growth and spread during this time.”

Researchers have already warned that, in any case, methane emissions are likely to increase as the world warms, with methane-emitting microbes inevitably flourishing in warmer waters. But, overall, there remains a case for preserving or restoring wetlands.

According to the WWF (formerly the World Wildlife Fund), the planet’s freshwater marshes, deltas, swamps, bayous and wetlands are home to 40% of all the world’s species and 12% of animal species.

Important buffers

Deltas and mangrove swamps also provide an important buffer to protect coasts – and coastal settlements – from storm surges, cyclones and even tsunamis, and their annual value in ecosystem services and as protective zones has been measured in trillions of dollars.

The World Resources Institute calculates that, ultimately, 90% of the ocean’s fish depend on deltas, estuaries and coastal wetlands as nursery and spawning grounds, as well as sources of nutrient. The loss of coastal wetlands has been linked to an increase in oceanic “dead zones”.

So the case for wetland restoration is a strong one, even on climate grounds. It soaks up carbon dioxide, and skilful plant management might, according to Dr Matthes, reduce the methane problem.

“It’s a little bit tricky in ecosystem engineering,” she says “but we are hoping to learn some things about how people might plan wetland vegetation in order to maximise carbon dioxide uptake, but to minimise methane release.” – Climate News Network

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Salt’s poisonous effect is growing threat to crops

Salt’s poisonous effect is growing threat to crops

As global warming increases the world’s arid areas, scientists warn that restoring productivity to salt-affected agricultural land will be essential to feed an expanding population.

LONDON, 1 November, 2014 − Salt is poisoning around 2,000 hectares of irrigated farm land every day – and has been doing so for the last 20 years, according to new research.

Think of an area about the size of 3,000 football fields that can no longer be used to produce food each day. And then remember that the global population actually grows by around 200,000 people every day.

Manzoor Qadir, senior research fellow at the United Nations University’s Institute for Water, Environment and Health, and colleagues report in the journal Natural Resources Forum that an area of farmland the size of France – 62 million hectares – has been affected by the build-up of salts in irrigated soil. This is one-fifth of all irrigated land.

“To feed the world’s anticipated nine billion people by 2050, and with little new productive land available, it’s a case of all lands needed on deck,” says Dr Qadir. “We can’t afford not to restore the productivity of salt-affected lands.”

Ancient hazard

Salts degradation is an ancient hazard in arid and semi-arid lands, where groundwater is pumped from aquifers below the bedrock and used to grow crops.

Evaporation and transpiration leave precipitated salts around the roots of each crop and – since there is no fresh rainwater to wash away the salts − sooner or later the levels build up to intolerable scales, and the land becomes increasingly unproductive.

The UN Food and Agriculture Organisation warns that to feed the projected 2050 population, farmers will need to grow 70% more food. Cereal production alone will have to increase by 50%, to a total of three billion tonnes a year. But, each week, the world loses an area of land the size of Manhattan to salt degradation, thanks to poor soil management, bad drainage and other problems.

The researchers, from Canada, Jordan, Pakistan and Sri Lanka, based their estimates on more than 20 studies in the last two decades in Australia, India, Pakistan, Spain, Central Asia and the US.

They also totted up the estimated economic losses: more than $27 billion a year.

In the Indo-Gangetic basin of India, the build-up of soil salts could reduce wheat harvests by 40%, and cotton by more than 60%.

Employment losses could be as much as 50-80 man days per hectare, and human health problems could be between 20% and 40% greater because of the effect. Animal health problems could increase by anywhere between 15% and 50%.

In the Indus basin in Pakistan, the average overall wheat grain loss has been put at 32%, and the average rice yield has fallen by 48%.

The worst affected regions of the world are the Aral Sea basin in Central Asia, the Indo-Gangetic basin in India, the Indus Basin in Pakistan, the Yellow River basin in China, the Euphrates basin in Syria and Iraq, the Murray-Darling in Australia, and the San Joaquin Valley in the US.

The researchers warn that their calculations concern only crop-yield losses.

“Salt-affected degraded lands emit more greenhouse gases, thus contributing to global warming”

“However, the crop yields from irrigated areas not affected by salinisation have increased since 1990 due to factors such as improved crop varieties, efficient on-farm practices, better fertilizer use, and efficient water management practices,” they say.

“Consequently, there may be larger gaps in crop yields harvested from salt-affected and non-affected areas under similar agro-ecosystems, suggesting an underestimation of the economic cost of salt-induced land degradation.”

“These costs are expected to be even higher when other cost components − such as infrastructure deterioration (including roads, railways, and buildings), losses in property values of farms with degraded land, and the social cost of farm businesses − are taken into consideration.

“In addition, there could be additional environmental costs associated with salt-affected degraded lands as these lands emit more greenhouse gases, thus contributing to global warming.”

Some yield could be recovered. For example, farmers could irrigate more sparingly, plough deeply, dig drains, plant trees, select salt-tolerant crops, and dig in the stubble and plant waste.

An essay in the journal Trends in Plant Sciences also notes that around three hectares of farmland are lost every minute.

But plant science itself could help. Sergey Shabala, professor of crop physiology and plant nutrition at the University of Tasmania in Australia,  points out that millions of years of evolution have already devised a possible answer.

He says: “We should learn from nature and do what halophytes, or naturally salt-loving plants, are doing: taking up salt but depositing it in a safe place – external balloon-like structures called salt-bladders.”

Over-riding problem

New approaches to plant breeding could certainly provide part of the solution. The over-riding problem, however, is that water is already being used on a prodigal scale, in a globally-warming world in which some regions are in any case predicted to become even more arid.

Nine-tenths of the Aral Sea – once the world’s fourth largest lake − in Central Asia is now a sandy desert. The dust blown from it has salted half of Uzbekistan’s soil, and 70% of Turkmenistan has become desert, according to a report in the journal Nature.

But the cotton and wheat farmers in the republics that border the Aral Sea are among the highest users of water in the world. A Turkmen, on average, consumes four times the water used by a US citizen, and 13 times that of a Chinese one.

And although the Western hemisphere is in the grip of a calamitous and sustained drought, the real problem, according to Marcia McNutt, the former director of the US Geological Survey, and now the editor-in-chief of Science magazine, is that underground aquifers in the south-western US have been emptied for irrigation at such a rate that the contours on the land itself have started to change.

Californian mountains have risen up to 15 millimetres because of the water loss.

“It is high time we started managing our precious water supplies in harmony with the laws of nature,” she warns. – Climate News Network

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Climate renews famine risk to Africa’s Sahel

Climate renews famine risk to Africa’s Sahel

With population increasing and food demand far outstripping supply, the Sahel is vulnerable to a new humanitarian crisis − and researchers warn that rising temperatures will only make matters worse.

LONDON, 20 October, 2014 − The Sahel, the arid belt of land that stretches from the Atlantic to the Red Sea and separates the Sahara desert from the African savanna, is no stranger to drought and famine.

Now scientists in Sweden say the Sahel faces another humanitarian crisis even than in the recent past − with the changing climate partly responsible.

Writing in the journal Environmental Research Letters, the researchers from Lund University say people in the Sahel need more food, animal feed and fuel every year. But demand, which has more than doubled over a recent 10-year period, is growing much faster than supply.

Fewer resources

Data from 22 countries shows the result: fewer resources per capita and a continued risk of famine in areas with low primary production – that is, the availability of carbon in the form of plant material for consumption as food, fuel and feed.

Human numbers are part of the reason. Between 2000 and 2010, the population of the Sahel grew from 367 million to 471 million people − an annual rise of 2.2% over the decade.

But crop production remained essentially unchanged, so the margin between supply and demand for primary production is shrinking every year, while the Sahel’s population is forecast to total nearly a billion people by 2050.

Children's graves at a refugee camp in Kenya during the famine in 2011 Image: Andy Hll/Oxfam via Wikimedia Commons
Children’s graves at a Kenyan refugee camp during the 2011 famine
Image: Andy Hall/Oxfam via Wikimedia Commons

Some studies suggest that modern plant strains can withstand the effects of drought better than traditional cultivars, although this was not a focus of the Lund team.

They were mainly concerned with the staple crops grown regionally − such as sorghum and millet, which are used as food for people, with the residues used as fodder for livestock − and with the dry woodlands that provide fuel.

They used remote analysis and satellite images to calculate annual crop production in the 22 countries they studied, and compared the figures with data on population growth and consumption of food, animal feed and fuel. This relationship helps to measure a region’s vulnerability.

The study shows that 19% of the Sahel’s total primary production in 2000 was consumed. Ten years later, consumption had increased to 41%.

Reduced harvest

It says several forecasts suggest that harvests will be reduced as a result of the higher air temperatures the region is now experiencing, even though climate change is predicted to result in the Sahel receiving more rain in future.

So, the researchers say, climate change can only increase the vulnerability of the Sahel.

Asked by the Climate News Network whether higher air temperatures alone were likely to cancel the gains from increased rainfall, one of the study’s authors, Hakim Abdi, a doctoral student in physical geography and ecosystem science at Lund, said: “The short answer is yes. Studies indicate that higher temperatures offset both increased rainfall and CO2 fertilisation.

“Additionally, a recent study found that increase in future rainfall in the Sahel, a region where the soil generally receives little nutrient input and is over-exploited, causes nutrient leaching, and hence induces nitrogen stress.

“When we were in our study site in North Kordofan in Sudan, the most common complaint we received from the villages we visited was the lack of water.

“I think that if a drought occurs with an impact that matches or exceeds the ones in 1972/73 or 1982/83, we will see serious consequences − worse impacts than past ones.” − Climate News Network

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Seaweed problem could provide biofuel solution

Seaweed problem could provide biofuel solution

Biofuels are controversial because they are often produced from food crops or grown on farmland, but a common algae found in abundance around coastlines and clogging up beaches may be the answer.

LONDON, 19 October, 2014 – It has often been used as a farmland fertilizer, and in some communities it is eaten as a vegetable, but now researchers believe that seaweed could power our cars and heat our homes too.

One species of algae in particular, sugar kelp (Laminaria saccharina), is exciting scientists from Norway. It grows prolifically along the country’s coasts and, as its name suggests, contains a lot of energy − about three times as much sugar as sugar beet. That makes it suitable for turning into food and fuel.

Sugar kelp uses excess nitrogen in the sea, and so cleans up fertilizer pollution. However, it can grow so fast it can be clog beaches and needs to be removed, so finding an economic use for it would solve many problems.

Scientists are competing to see who can get convert seaweed into fuel most efficiently.

One of them is Fredrik Gröndahl, a KTH Royal Institute of Technology researcher and head of the Seafarm project. He believes the algae are being upgraded from an environmental problem into a valuable natural resource and raw material.

“The fact is that algae can absorb nitrogen from the water as effectively as a wastewater treatment plant,” Gröndahl says,

Eco-friendly resource

In some places, it is so prolific that it disrupts normal activities along the shoreline, but Trandahl’s project converts algae into eco-friendly food, medicine, plastic and energy. “We see algae as a resource,” he says. “We collect excess algae along the coasts, and we cultivate new algae out at sea.”

The seaweed is being scooped up from the Baltic Sea, along Sweden’s southern coast, in order to be converted to biogas. It is a coast rich with the seaweed, and the city of Trelleborg estimates that its beaches host an excess of algae that is equivalent to the energy from 2.8 million litres of diesel fuel.

The first algae farm is already up and running, near the Swedish town of Strömstad, in the waters that separate the country from Denmark. The Seafarm project will, according to Gröndahl, contribute to the sustainable development of rural districts in Sweden. “We create all-year-round jobs,” he says.

One example is in the “sporophyte factory farms” on land where, to begin with, the algae are sown onto ropes. When miniature plants (sporophytes) have been formed, they sink and are able to grow in the sea. After about six months, when they algae have grown on the ropes, they are harvested and processed on land through bio-refining processes.

Grow rapidly

“It will be an energy forest at sea,” Gröndahl says. “We plan to build large farms on two hectares right from the start, since the interest in the activities will grow rapidly when more farmers and entrepreneurs wake up to the opportunities and come into the picture.

“In 15 years’ time, we will have many large algae cultivations along our coasts, and Seafarm will have contributed to the creation of a new industry from which people can make a living.”

Another line of research, using the same kind of seaweed, has been revealed by Khanh-Quang Tran, an associate professor in the Norwegian University of Science and Technology (NTNU) Department of Energy and Process Engineering. He has been producing what he calls bio-crude.

“What we are trying to do is to mimic natural processes to produce oil,” says Khanh-Quang Tran, whose results have been published in the academic journal, Algal Research. “However, while petroleum oil is produced naturally on a geologic timescale, we can do it in minutes.”

Using small quartz tube “reactors” – which look like tiny sealed straws – Tran heated the reactor, containing a slurry made from the kelp biomass and water, to 350˚C at a very high rate of 585˚C per minute. The technique, called fast hydrothermal liquefaction, gave him a bio-oil yield of 79%. That means that 79 % of the kelp biomass in the reactors was converted to bio-oil.

A similar study in the UK, using the same species of kelp, yielded only 19%. The secret of much higher yields, Tran says, is the rapid heating.

Carbon-neutral

Biofuels that use seaweed could lead humans towards a more sustainable and climate-friendly lifestyle. The logic is simple: petroleum-like fuels made from crops or substances take up CO2 as they grow and release that same CO2 when they are burned, so they are essentially carbon-neutral.

The problem of using food crops has led many to question whether bio-fuels are a solution to climate change. So to get around this problem, biofuel is now produced from non-food biomass, including agricultural residues, and land-based energy crops such as fast-growing trees and grasses.

However, seaweed offers all of the advantages of a biofuel feedstock, and has the additional benefit of not interfering with food production.

But while Tran’s experiments look promising, they are what are called screening tests. His batch reactors are small and not suitable for an industrial scale. Scaling up the process requires working with a flow reactor, one  with a continuous flow of reactants and products. “I already have a very good idea for such a reactor,” he says.

Tran is optimistic that he can improve on a yield of 79%, and is now looking for industrial partners and additional funding to continue his research. – Climate News Network

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Wind turbines may lure bats into fatal errors

Wind turbines may lure bats into fatal errors

Hi-tech thermal surveillance techniques have enabled US researchers to hone in on the likelihood that mistaking wind turbines for trees may be the cause of many bat deaths.

LONDON, 12 October, 2014 − Scientists in the US might just be about to answer one of the great puzzles of biodiversity and renewable energy: why one of nature’s most agile flyers, a creature with the most sophisticated ultrasonic tracking system, should be so fatally attracted to wind turbines.

Blades on the giant towers of wind turbines can rotate faster than a bird can fly, and are known to cause huge numbers of bird fatalities. The bigger mystery is why they kill so many bats.

These nocturnal flying mammals perform their aerobatics at bewildering speed. They can detect and snap up an insect on the wing, and so collision with a wind turbine blade ought to be about as rare as collision with a building or a tree.

But there is no doubt about bat losses. Researchers have already estimated that US wind farms account for 600,000 or more of the creatures every year. And this is not good news − particularly as some experts think bats may be worth $3bn a year to US farmers as pest controllers.

Curious parallel

Now research biologist Paul Cryan and colleagues from the US Geological Survey’s Fort Collins Science Center in Colorado report in the Proceedings of the National Academy of Sciences on a curious parallel: the species most likely to die near a wind turbine are those that are most likely to nest in trees.

And the conditions that bring the greatest number of deaths are not the high winds that send the blades racing through the air at a lethal 280 kilometres an hour, but the relatively gentle breezes of the kind that bats might experience as the familiar air currents in woodland when the insects are out in their millions..

In other words, it is just possible that bats – which notoriously cannot see very well – are led by their echolocation system to believe that they are flitting around a tree.

In 2012, at a wind farm in Indiana, Dr Cryan and his fellow researchers monitored the behaviour of bats with thermal surveillance cameras, near-infrared video cameras, acoustic detectors, and radar. Altogether, they detected more than 3 million animals flying through their target zone. A quarter of these were vertebrates, and four-fifths of these vertebrates were clearly identified as bats.

After each night’s surveillance, they also found about a dozen freshly dead bats, but very rarely did their video cameras actually observe a fatal impact.

Behaviour pattern

However, they identified a behaviour pattern. Bats were more likely to approach a turbine during low winds, and they were less likely to approach from downwind as wind speeds increased and turbine blades moved freely.

So the logic works like this: bats orient towards the turbines when the air currents are the sort they might expect to find around tall trees where the insects are gathered, or because they normally roost in tall trees.

Such findings are provisional, and there is more work to be done. But the hypothesis does help explain why it should be tree-roosting bats that suffer most losses.

“Behaviours that evolved at tall trees might be the reason why many bats die at wind turbines,” the report concludes. – Climate News Network 

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