Antarctica blows hot and cold – for now

Antarctica blows hot and cold – for now

Natural variability may at the moment be affecting Antarctica’s temperature more than human activity, but climate change will still be a major influence.

LONDON, 19 April, 2015 – German scientists have identified a pattern of natural change in Antarctica. The discovery appears to suggest that human influence may not be a cause of apparent warming in the seas around the great, frozen continent. Instead, natural variability might have a role.

The finding doesn’t undermine the thesis that human burning of fossil fuels is enriching the atmosphere with greenhouse gases and triggering climate change: it might however account for the so-called pause in the rate of warming this century.

The verdict remains inconclusive. But new evidence published in the journal Climate Dynamics introduces a new layer of complexity in the understanding of the planetary climate system.

In brief, the rate of warming in the northern hemisphere is considerable, and highest in the Arctic Circle. Overall, the southern hemisphere remains colder, and evidence from the Antarctic has been ambiguous, although there have been widely reported fears of potentially dramatic change in West Antarctica. Rapid melting in the region would constitute a “climate tipping point” which would have consequences across the entire planet.

Too simple

But Josef Ludescher of the Institute for Theoretical Physics at the Justus Liebig University of Giessen and colleagues made an analysis of the full range of air temperature records from the southern continent and decided that the simple picture of a consistently cold and hostile world possibly modified by human activity was too simple: instead they found a propensity for “large and enduring natural excursions from the mean.”

Put simply, sometimes the winds blow colder, sometimes not quite so cold, but the coldest spells last for decades, followed by extended periods that might be measurably warmer overall.

The finding – it is based on sophisticated mathematical analysis and like all such hypotheses invites both confirmation and demolition by other climate science researchers – has a consequence: it means that the warming now observed in Antarctica may not be because of human influence. Or it may be that any human influence is so far swamped by a larger cyclic shift between two natural states.

“So far it seemed that there were hardly any major natural temperature fluctuations in Antarctica, so almost every rise in temperature was attributed to human influence,” said Armin Bunde of the Justus Liebig University, another member of the team.

“Global warming as a result of our greenhouse emissions from burning fossil fuel is a fact. However the human influence on the warming of West Antarctica is much smaller than previously thought. The warming of East Antarctica up to now can even be explained by natural variability alone.”

“At the end of this natural cold spell temperatures will rise even more fiercely – globally, but also in Antarctica”

But the study – if backed by other findings – could explain another climate puzzle. Although global warming increased rapidly during the last three decades of the last century, the rate of warming has slowed. All but one of the hottest years ever recorded have been in this century, and 2014 broke all records, but the rate at which the temperatures have risen has slowed.

There have been many potential explanations for this apparent slowdown. And perhaps the proposed Antarctic cycle has a role in that too.

“Our estimates show that we are currently facing a natural cooling period – while temperatures rise slowly but inexorably, due to our heating up the atmosphere by emitting greenhouse gases,” said another of the authors, Hans Joachim Schellnhuber, of the Potsdam Institute for Climate Impact Research.

“At the end of this natural cold spell temperatures will rise even more fiercely – globally, but also in Antarctica, which therefore is in danger of tipping.” – Climate News Network

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Polar bears weakened by pollution as well as warmth

Polar bears weakened by pollution as well as warmth

Climate change causing habitat loss and reduced food is the main problem for polar bears, but plastic waste and other pollutants are growing risks.

LONDON, 17 April, 2015 − Greenland’s polar bears have a thyroid problem. Their endocrine systems, too, are being disrupted. In both cases the culprit agency is environmental pollution by a range of long-lived industrial chemicals and pesticides.

Kristin Møller Gabrielsen of the Norwegian University of Science and Technology in Trondheim and colleagues report in the journal Environmental Research that they examined the liver, muscle and kidney tissues taken from seven polar bears killed by Inuit hunters in East Greenland in 2011 and analysed the effect of more than 50 contaminants in plasma samples from Ursus maritimus, to see what effect organohalogen compounds could have on the bears’ thyroid systems.

All mammals have thyroid systems, and these are physiologically essential for growth, development, reproduction, stress response, tissue repair, metabolism and thermoregulation (an animal’s ability to keep its body temperature within limits): disruption at any stage of life can be damaging, but thyroid regulation is vital in the earlier stages of life.

But the researchers found high concentrations of plastic pollution and pesticide contamination in the creatures’ tissues, many of which could affect the hormonal systems.

Retreating ice

Polar bears face an uncertain future: the Arctic’s most iconic predator depends on sea ice for access to the most nourishing prey – seals − but thanks to global warming driven by greenhouse gases discharged by humankind since the start of the Industrial Revolution, the ice is in retreat. The bears can and do forage on land for small prey, eggs, berries and so on, but new research suggests that this is unlikely to help them much.

“The health of the Arctic polar bear is being attacked from all fronts, but among many other factors is the exposure to environmental contaminants,” said Maria Jesus Obregon, of the Biomedical Research Institute in Madrid, one of the authors.

“A wide variety of organochlorine compounds and pesticides have an effect on the thyroid hormones in plasma, tissues and deiodinase enzymes, which are in charge of stabilising the thyroid hormones in tissues.”

The biggest problem that confronts Ursus maritimus is still climate change, loss of habitat and a more precarious food supply. But as a marine mammal, the bear is exposed to a huge range of pollutants delivered by modern industry, transport and commerce.

Conservation guidelines

Researchers in February calculated that in 2010, around eight million tons of plastic waste
ended up in the world’s oceans.

A second team of researchers has framed guidelines for the conservation of the polar bear, and proposed 15 measures that could determine the factors important in saving the creature from ultimate extinction.

They report in the journal Science of the Total Environment that they questioned 13 specialists from four nations to propose ways of measuring polar bear health. Not surprisingly, climate change topped the list of threats, but the list also included nutritional stress, chronic physiological stress, diseases and parasites, and increasing exposure to competitors. Exposure to contaminants was the third largest threat.

“We still don’t know to what extent environmental changes will affect polar bear health and therefore its conservation,” say the authors. − Climate News Network

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Carbon dioxide triggered ancient mass die-off

Carbon dioxide triggered ancient mass die-off

The biggest extinction ever known on Earth resulted from oceans turned acid by CO2, the main gas driving human-caused climate change today.

LONDON, 16 April, 2015 − Scientists have identified the lethal agency that caused the single most catastrophic event in the history of life on Earth. The mass extinction at the boundary of the Permian and Triassic eras 252 million years ago was caused by the acidification of the world’s oceans, as a consequence of an increase in atmospheric carbon dioxide.

The Permian Extinction – sometimes called “the Great Dying” – seemed to all but obliterate life in the oceans, and perhaps on land. More than 90% of all species disappeared, more than 80% of all genera, and more than 50% of all marine families were extinguished in one prolonged calamity.

All life on Earth today has descended from the few survivors of this far-off episode. Palaeontologists, geologists, climate scientists and astronomers have all speculated on the probable cause. The latest and most confident analysis is based on a new study of ancient marine sediments and delivers obvious parallels with processes that are – for different reasons − occurring again today.

Matthew Clarkson of the University of Edinburgh in Scotland (but now at the University of Otago in New Zealand) and colleagues report in the journal Science that they examined limestone from the United Arab Emirates and found, in the isotope ratios of the element boron, evidence of ocean acidity in carbonate rocks that were laid down as sediment at the bottom of the ocean 250 million years ago. A change in the isotope ratios, they calculated, would have indicated a significant shift in seawater chemistry.

“This is a worrying finding, considering that we can already see an increase in ocean acidity today that is the result of human carbon emissions”

Over the last 40 years, researchers have introduced a whole suite of plausible triggers for the Permian extinction, but at last one team had clear evidence of increased atmospheric carbon, probably from a prolonged and convulsive series of volcanic eruptions that gave rise to vast, ancient geological formations now known as the Siberian Traps.

“Scientists have long suspected that an ocean acidification event occurred during the greatest mass extinction of all time, but direct evidence has been lacking until now”, said Dr Clarkson. “This is a worrying finding, considering that we can already see an increase in ocean acidity today that is the result of human carbon emissions.”

There has been recent evidence that this present change in the pH of ocean waters (pH is a measure of its acidity) as a consequence of fossil fuel combustion in the last two centuries has already disturbed the behaviour of some fish species, threatened to affect oyster fisheries and coral reefs, and even to alter whole ocean ecosystems.

The changes in the Permian were not sudden: ecosystems already seriously under stress because of lack of oxygen or rising temperatures were then dramatically affected by discharges of carbon dioxide that were probably much greater than all the modern world’s existing fossil fuel reserves could deliver. As the oceans became more acidic, many species were extinguished forever: among them the trilobites.

The whole chain of events took 60,000 years. Humans have been burning fossil fuels for only 200 years, but, the researchers point out, in the Permian crisis, carbon was probably being released into the atmosphere at the rate of about 2.4 billion tons a year. Right now, humans are estimated to be releasing carbon from fossil fuels at the rate of 10 billion tons a year. − Climate News Network

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Too much nitrogen reduces Alpine plant diversity

Too much nitrogen reduces Alpine plant diversity

Climate change caused by one of the less abundant greenhouse gases is playing havoc with plant life in Switzerland, posing problems for other forms of life and increasing the risk of erosion.

LONDON, 15 April, 2015 − Carbon dioxide isn’t the only greenhouse gas to change the world. Swiss scientists have just confirmed that nitrous oxide and other forms of atmospheric nitrogen deposition – from agriculture, from factory chimneys and motor exhausts and so on – is altering the grasses and wildflowers of the Alps and the valleys.

Plants cannot live without nitrogen: for most of evolutionary history, it has been available only in limited amounts. With the Industrial Revolution, that began to change. Tobias Roth of the University of Basel and colleagues report in the Royal Society journal Open Science  that the historic rise in the availability of nitrogen has reduced plant diversity everywhere in Switzerland.

The finding is not – of itself – new. Researchers tested the hypothesis that increasing levels of nitrogen presented a threat to “hotspots” of global biodiversity almost a decade ago. But in science, one general study is never enough.

More nitrogen

So Dr Roth and his colleagues did something much more detailed and comprehensive. They used six different measures of plant diversity to test what was happening on 381 study plots at a variety of altitudes and in different kinds of ecosystems across just one country. However the scientists measured plant diversity, it had been reduced.

That human-triggered changes to the atmosphere have affected Switzerland is not in much doubt: one research team recently established that alpine glaciers were in retreat in response to atmospheric pollution, and Dr Roth – now with the Swiss company Hintermann and Weber AG – last year demonstrated that birds, flowers and butterflies in the country were all heading uphill in response to global warming.

The latest research began with a baseline from earlier centuries: data taken from herbarium samples confirmed that available nitrogen had once been much more limited. The scientists then randomly selected 428 study plots – each a kilometre square – as their study samples.

Some had to be rejected, because they were entirely water, or in mountainous regions too rugged and dangerous for field research. But that left 381 sample plots, in the Alps and the Jura mountains, between the altitudes of 260 and 3,200 meters (850 and 10,500 feet).

Bad news

The researchers used qualified botanists who had received special training to conduct the surveys, and asked them to conduct, as closely as they could, a diagonal transect examination across each plot, if possible once in spring and again in summer, and to record all vascular plants. Altogether, the surveys delivered 93,621 observations of 1,768 plant species.

The scientists found that biodiversity had declined by 19% according to one measure and by 11% in another test. In general, the higher the nitrogen available, the lower the diversity.

This is bad news for ecosystems as a whole: diversity means stability. Extra sources of nitrogen fertility benefit some highly competitive groups of plants, at the expense of others.

“High plant diversity is important to us humans for many reasons,” said Valentin Amrhein, another of the authors. “For example, in the mountains a large number of plant species with different root depths will stabilise the soil more effectively and prevent erosion.” − Climate News Network

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Permafrost holds key to release of trapped carbon

Permafrost holds key to release of trapped carbon

The frozen soil of the northern polar regions holds billions of tonnes of organic carbon – and global warming could speed its escape into the atmosphere.

LONDON, 14 April, 2015 − Three sets of scientists in the same week have helped narrow the uncertainties about how the natural world will respond to extra carbon dioxide in the atmosphere caused by the burning of fossil fuels.

Carbon locked in the frozen earth will escape gradually as the Arctic permafrost melts – but the scientists say the process could accelerate.

As greenhouse gas levels soar, and soils warm, and plant roots tap down into the carbon stored there by centuries of ancient growth, they will release potent chemicals that will accelerate microbial attack – and speed up the release of carbon dioxide into the atmosphere.

The soil carbon cycle is one of the great headaches of climate science. And the Arctic is the first place to look for answers about it, and about how the Earth and oceans that store atmospheric carbon will respond to global warming.

Locked away

Around half of the world’s buried organic carbon is locked away in the soils of the northern circumpolar permafrost, and this huge vault of deep-frozen peat and leaf litter – more than 1,000 billion metric tonnes in the top three metres, at the latest estimate − contains twice as much carbon as is held in the atmosphere.

But the Arctic is the fastest-warming region on the planet, so what will happen as the permafrost thaws and plants begin to move north? Would it all be surrendered to the atmosphere in one devastating exhalation, triggering an explosion in global warming and causing trillions of dollars in economic damage?

An international team within the Permafrost Carbon Network thinks not. Their verdict, published in Nature journal, is that the current evidence suggests “a gradual and prolonged release of greenhouse gas emissions in a warming climate”. That is, humankind would have time to adapt.

“The data from our team’s syntheses don’t support the permafrost carbon bomb view,” says one of the team members, David McGuire, professor of landscape ecology at the University of Alaska Fairbanks.

“What our syntheses do show is that permafrost carbon is likely to be released in a gradual and prolonged manner, and that the rate of release through 2100 is likely to be of the same order as the current rate of tropical deforestation in terms of its effects on the carbon cycle.”

Since the tropical forests are already under pressure, this is hardly good news. And the picture is not a simple one.

“Even small changes will have serious effects on carbon concentrations in the atmosphere, and by extension on climate”

As the permafrost thaws, the soil microbes will get to work on the buried carbon, which will inevitably add to the soil warming, and provide an instance of what engineers call positive feedback, according to a team led by Jøgen Hollesen, senior researcher at the University of Copenhagen’s Centre for Permafrost.

He and colleagues report in Nature Climate Change that when they measured heat production in 21 contrasting organic permafrost soils, they found it to be between 10 and 130 times higher than in mineral soils measured in Greenland − and this would have “crucial implications for the amounts of carbon being decomposed”.

And in the same issue of Nature Climate Change, a team led by researchers from Oregon State University have confirmed that any kind of warming or plant growth is likely to get the soil microbes working as hard as they can – partly because the plants use chemistry to free the soil carbon so the bacteria can start to turn it back into carbon dioxide.

Neither of the two Nature Climate Change studies was directly concerned with climate change. The Danish scientists’ findings sprang from concern about what warming might do to the ancient middens that hold as-yet-unexamined evidence of early human settlement in the Arctic. The Oregon team were more concerned about the interactions that go on in the soil, and how they could be measured.

Chemical bonds

They found that plant roots released an exudate that acted to release the chemical bonds that keep a carbon bound to non-organic minerals in the soil. Warming could only speed the process, so more carbon dioxide will get into the atmosphere from the soil because of global warming.

This, again, is positive feedback at work. And it suggests climate scientists might be underestimating carbon loss from the soil by as much as 1% a year.

“Our main concern is that this is an important mechanism, and we are not presently considering it in global models of carbon cycling,” says soil and environmental geochemist Markus Kleber, one of the authors of the Oregon report.

“There is more carbon stored in the soil, on a global scale, than in vegetation, or even in the atmosphere. Since this reservoir is so large, even small changes will have serious effects on carbon concentrations in the atmosphere, and by extension on climate.” – Climate News Network

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Unfinished nuclear plants raise safety doubts

Unfinished nuclear plants raise safety doubts

A new generation of giant reactors, meant to provide fresh hope for nuclear power in Europe, has been found to have a serious safety problem.

LONDON, 13 April, 2015 − The future of the world’s biggest nuclear reactor, under construction at Flamanville in northern France, is now in doubt after a serious flaw was found in its steel pressure vessel.

Examination has shown that the steel contains too much carbon, which can weaken the vessel’s structure and breaches safety rules. The Chinese, who have two similar 1,600 megawatt European Pressurised Reactors under construction, have been warned that they too may share the potentially catastrophic problem.

Investigations are continuing to check whether the problem can be rectified, but whatever happens it will add more delays and greater costs to the already troubled projects.

The problem also casts doubt on the much-heralded nuclear renaissance in Europe, where EPR reactors are being built not only in France but also in Finland.

Four more are planned for Britain, where they form a cornerstone of the UK government’s policy to fight climate change. A decision on whether to go ahead with the first two in the UK has already been postponed twice, and this revelation will cause further delays.

The French nuclear engineering firm Areva, involved in the EPR’s design and development, found the flawed steel and reported the problem to the country’s nuclear regulator, ASN, which has ordered an investigation.  The French energy minister, Ségolène Royal, says the results of tests to check the extent of the problem will be released in October.

Serious blow

It is understood that the maximum allowable carbon content of steel in the pressure vessel is 0.22%, but tests have shown 0.30% in parts of the Flamanville vessel. This could render it subject to cracking in operation and shorten its intended lifespan.

The discovery is another serious blow to the French nuclear industry, which already faces severe financial problems, partly because of existing delays to the reactors at Flamanville and at Finland’s Olkiluoto site. The Finnish reactor, which is not affected by this problem because its pressure vessel steel comes from Japan, not France,, is already nine years behind schedule for other reasons and has more than doubled in cost.

Following the 2011 Fukushima disaster in Japan any compromise on minimum safety standards would be hard to sell to the public, especially since nuclear power has fallen out of favour with the French government, which wants to invest heavily in renewables.

France is already considering merging Areva and Électricité de France (EDF), the two nuclear companies in which it owns the majority of shares. Areva is building the Flamanville reactor on behalf of EDF, Europe’s largest electricity producer.

EDF recently estimated the construction costs of Flamanville at €8 billion (US$8.7bn) compared with an original estimate of €3.3bn, and that was before this setback. The plant was due to have been working by now, but its start date had already been put back to 2017 – which is now looking optimistic.

It is understood that the parts of the pressure vessel found with excess carbon were manufactured in France at the Creusot Forge, in Burgundy, owned by Areva. It was this same company that made parts for the two Chinese reactors, hence the fears that they too will contain carbon above safety limits.

Large subsidies

One problem is the pressure vessel’s sheer size and the fact that it was already in place when the fault was detected. The vessel weighs 410 tonnes and cannot now be removed, and it is hard to see how it could be repaired or modified.

The problem was discovered in December but made public in a low-key website announcement only on 7 April.

One knock-on effect might be to seriously damage the British government’s own energy policy, which relies on building four similar reactors in England. Work has already been completed on preparatory works for two at Hinkley Point, in the west of England, using the Flamanville design.

The UK government has agreed large subsidies to support the projects, but EDF has repeatedly delayed signing a final deal to build them, because of a lack of investors. Two Chinese utilities were negotiating to back the project financially, but the discovery of a flaw at Flamanville may complicate matters.

In any event, the decision on whether to go ahead with the two reactors at Hinkley Point had already been postponed until the summer and now seems certain to be postponed yet again until the issue of the safety of the French and Chinese pressure vessels has been resolved.

The UK government has repeatedly said that the expansion of nuclear power is vital to its energy security and its ability to meet its greenhouse gas reduction targets. The country is currently in the middle of a general election campaign. Whichever government gets into power may have to rapidly rethink its energy policy. − Climate News Network

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Forests can soak up a third of carbon emissions

Forests can soak up a third of carbon emissions

Report commissioned by Prince Charles’s charity says protecting tropical forests could enable them to absorb billions of tonnes of the Earth’s emissions of carbon.

LONDON, 11 April, 2015 − Looking after the world’s tropical forests would be worthwhile in its own right, for the sake of their human and animal inhabitants and their wider effects on the natural world.

But researchers say it would also have a significant bonus. Properly cared for, the forests could cancel out between a quarter and a third of the planet’s carbon emissions.

They argue that it is not just outright destruction of the trees that is the problem, but the ways in which the forests become degraded by the incursion of different forms of development − logging, obviously, but also fires, mining, ranching, roads, and their effect in splitting the huge tracts of forested land into smaller and more isolated patches.

In a report commissioned by Prince Charles, the heir to the British throne, they say deforestation and degradation of the forests may account together for between 14% and 21% (1.4-2.2 gigatonnes of carbon, or GtC; a gigatonne is a billion metric tonnes) of all emissions of carbon, and perhaps even more if tropical peatlands and mangroves are included.

Atmospheric carbon

Against this, the forests absorb almost as much atmospheric carbon as they account for − an annual total of 1.2-1.8GtC, the authors say. But the report argues that simply offsetting the amount of carbon sequestered in this way against the amount emitted is insufficient, for two reasons.

The first is the evidence that human activities are responsible for a significant proportion of CO2 absorption. Second, total emissions are probably much higher than the traditional greenhouse gas (GHG) accounting approach allows.

Taken together, these two factors suggest that slowing damage to the forests and keeping them in the best condition possible is more important than many people have realised.

But the forests continue to suffer damage. The report says: “…it can be argued that the causes and consequences of tropical forest degradation have been given too little attention, with the science now pointing toward degradation being a very significant component both of greenhouse gas emissions and the weakening of forest ecosystems”.

We can act on forests now, therefore buying much-needed time to enable the transformation to a low-carbon economy

It paints a sobering picture of the present situation, saying there is “no sign yet that overall rates of deforestation or degradation are decreasing”. The report says the annual area of global forest lost is about 8.5m hectares.

Rising world demand for timber and wood products, and for farm produce, it says, “will significantly increase pressure on tropical forests over the next few decades”.

The report was commissioned by the Prince’s International Sustainability Unit. In a foreword, Prince Charles writes: “It is an alarming fact that rates of deforestation and degradation continue to rise, and that the underlying causes of this increase are set to become very much more acute…”

But he sounds an encouraging note: “We can act on forests now, therefore buying much-needed time to enable the transformation to a low-carbon economy.”

Considerable uncertainty

There is considerable uncertainty about how much the forests contribute to GHG emissions. In 2012, NASA said that tropical deforestation had accounted for about 10% of human carbon emissions from 2000 to 2005 − a much lower figure than previous estimates.

Forest degradation is often more difficult to detect than deforestation itself, and is almost invisible to satellite monitoring. Research in six tropical countries suggests that degradation by logging can cause significant damage, with GHG emissions on average about 12% of those caused by deforestation.

Together, their impact is serious. The Global Forest Watch online monitoring network says that Brazil lost 5.9% of its forest cover between 2001 and 2012, while Indonesia lost 9.2% over the same timespan. − Climate News Network

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Woodlands revival adds new piece to carbon cycle puzzle

Woodlands revival adds new piece to carbon cycle puzzle

Growing number of trees on the world’s savanna grasslands helps offset carbon storage concerns caused by depletion of the great rainforests.

LONDON, 9 April, 2015 − Despite continuing concern about the fate of iconic rainforests, new research shows that the world’s forests have stored away an extra 4 billion tonnes of carbon in the last dozen years and the total amount of woodland has increased worldwide since 2003.

The encouraging news comes from Australian scientists, who report in Nature Climate Change that they used a new technique to analyse 20 years of satellite data, to estimate the overall pattern of growth in global vegetation.

The fate of the forests could hardly be more important. The world’s greenery is part of the natural atmospheric cycle, and the notorious greenhouse effect – the steady rise in carbon dioxide levels in the Earth’s atmosphere since the start of the Industrial Revolution and the use of fossil fuels to power economic growth – is in part also a response to land-use change and forest loss. Growth requires atmospheric carbon dioxide, and burning and land clearance releases it.

Biggest headache

So the study by remote sensing scientist Yi Liu, of the Climate Change Research Centre at the University of New South Wales, and colleagues becomes an important contribution to solving the climate scientist’s biggest headache: making sense of the carbon budget.

Accurate climate models depend on accurate assessment of the carbon cycle, and the forests play a critical role. Timber in the forests is essentially carbon in the bank.

And, for once, the news is encouraging. The great rainforests of the Congo and the Amazon may not be doing so well, but grasslands in other parts of the world have become increasingly more wooded, and there has been a massive expansion of forested land in China.

“The increase in vegetation primarily came from a lucky combination of environmental and economic factors, and massive tree-planting projects in China,” Dr Yi Liu says.

“Vegetation increased on the savannas of Australia, Africa and South America as a result of increasing rainfall, while in Russia and former Soviet republics we have seen the re-growth of forests on abandoned farmland. China was the only country to intentionally increase its vegetation with tree-planting projects.”

The Australian scientists are not the only researchers using instruments in high orbit to identify the green shoots of recovery.

“A lot rides on human decisions to slow
climate change. The clock is ticking
for the future of these forests”

Dmitry Shchepashchenko, a researcher at the International Institute for Applied Systems Analysis in Austria, and colleagues report in the journal Remote Sensing of Environment that a cocktail of remote sensing data, UN agency statistics and “crowdsourcing” – help from citizen scientists – has provided new high resolution maps of global forest cover.

This will serve as a basis for other studies, and for economic planning and policy-making. The maps are available on the Geo-Wiki website.

But the overall picture of a greener world remains uncertain. On the same day, scientists backed by the Carnegie Institution in Washington reported in Nature Geoscience that drought damage has already led to widespread forest death, and the toll could be much greater by the 2050s.

They based their study on the condition of the trembling aspen forests of the American southwest during the drought of 2000-2003.

Once again, their work is aimed at improving climate models and calculations of the response of forests to climate change, and could throw new light on the processes at work in forests subjected to water stress.

Drought damage

That is because the arboreal vascular system that transports water from the roots to the leaves is itself damaged by drought. But at what level would drought impose permanent damage on a tree’s physiology?

The Carnegie scientists were able to establish a drought threshold for the trembling aspen (Populus tremuloides), and the drought at the beginning of the century is known to have killed 17% of the species in Colorado.

The research is fundamental: just one study of one species in one region that provides a starting point for further studies, and thus for surer measures of vegetation response to climate change, and ultimately to a better understanding of the carbon cycle.

“Finding the thresholds in plant physiology, after which climate stress causes tree mortality, will allow us to resolve uncertainty over the fate of forest ecosystems in a changing climate,” says the study leader, William Anderegg, a researcher at Princeton Environmental Institute in the US.

“But, most importantly, a lot rides on human decisions to slow climate change. The clock is ticking for the future of these forests.” – Climate News Network

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Unhappy birthday for UK’s nuclear white elephants

Unhappy birthday for UK's nuclear white elephants

A state-of-the-art British plant designed to re-use spent nuclear fuel so as to cut greenhouse gas emissions is to close after years of what its critics call “commercial and technical failure.”

LONDON, 8 April, 2015 − Re-using uranium and plutonium as fuel for nuclear reactors over and over again to make unlimited quantities of electricity was the nuclear industry’s ambition 25 years ago, and central to its claim to be the solution to climate change.

Once uranium has been mined, enriched and used as reactor fuel it need not be wasted, the industry has argued. After its removal from the reactor so little of the potential energy it contains has been harnessed that the fuel can be reprocessed and used again. It is dissolved in acid, the impurities are removed, its uranium and plutonium are extracted and it starts the cycle again as new fuel.

In the 1980s the industry insisted that investment in the giant reprocessing plants was vital because by the millennium there would be 4,000 nuclear reactors worldwide, with too little uranium to fuel them all. In fact, by the end of the century there were only 434 reactors globally, and much more uranium had been found.

Some governments, including those of the UK, France, Germany and the US, believed the industry’s sales pitch, even though environmental groups like Friends of the Earth and Greenpeace never accepted it. Critics said the cost of building the reprocessing plants was too high, and feared the consequences of producing vast stockpiles of uranium and plutonium which might never be used in reactors.

Public opposition was so great in Europe that some countries, notably Germany, abandoned the idea, but Britain went ahead. The British plant was at Sellafield in Cumbria, north-west England.

Proved right

Martin Forwood, from Cumbrians Opposed to a Radioactive Environment (CORE), said: “We never believed there would be a huge expansion in nuclear energy or that there was any need for reprocessing, We said the discharges of nuclear waste into the Irish Sea that it entailed could not be justified, and we have been proved right.”

Despite many objections the nuclear industry got the UK government to accept reprocessing as essential to ensure future expansion. This spring is the 21st anniversary of the official opening of the Thermal Oxide Reprocessing Plant (THORP) at Sellafield, designed to dissolve both British and foreign spent fuel and retrieve the plutonium and uranium.

It cost £2.85 billion (US$4.25 bn) to build and in its first 10 years it planned to reprocess 7,000 tonnes of spent fuel and make £500 million (US$745 m) profit.

Contracts had been signed in advance with Germany, Japan, Switzerland and other countries with nuclear power stations to reprocess their fuel in England.

But technical faults meant THORP failed to meet its targets, and after a decade only 5,045 tonnes had been reprocessed. The plant’s real profits or losses have never been disclosed.

Despite this doubtful beginning the British government sanctioned another enterprise, a brand new factory to turn the plutonium and uranium that had been produced into new fuel. The idea was to sell it back to the countries that originally owned it, closing the recycling loop.

Unworkable theories

New contracts were signed with Switzerland, Germany and Japan to produce 120 tonnes of MOX fuel (mixed oxides of plutonium and uranium) annually. But unfortunately the British nuclear industry could not translate its theories into practice.

The new plant did not work as planned, producing only 13 tonnes of fuel in ten years. Originally it was said to have cost £280m (US$415m). After Japan’s Fukushima accident it was decided to close the plant. The total loss to the British taxpayer for this failure was later admitted to be £2.2bn (US$3.3bn).

Despite the fact there was now no market or use for the plutonium and uranium it was producing from the spent fuel, the original THORP plant has continued to operate. It was periodically closed after a series of accidents and technical failures, and had been reduced to operating at half its original throughput, but was always given permission to restart, arguing that it still had foreign contracts to fulfill.

As a result Britain now has the world’s largest stockpile of used plutonium, about 100 tonnes of it British and 30 tonnes belonging to other governments. If it were all converted into nuclear weapons it would be enough to destroy all life on Earth.

There are also around 7,000 tonnes of uranium, for which there is currently no use and which must remain under armed guard night and day for fear of terrorist attack.

“Two white elephants don’t make for success at Sellafield”

After years of indecision about how to deal with this unwanted surplus it has been announced that THORP should close in 2018 when all the foreign fuel has been reprocessed. Even after closure it will take years to decommission the plant and remove the waste, so not all of the 800 workers will lose their jobs at once and many will be re-deployed on other parts of the Cumbrian site.

Martin Forwood concludes: “That THORP should have failed so badly at so many levels comes as little surprise to those of us who warned − even before the plant opened − that the economics of the highly complex plant simply did not stack up and that worldwide demand for the uranium and plutonium that THORP would recover had already evaporated.

“Attempts to convert THORP’s plutonium into new fuel in an adjoining plant were equally disastrous…Two white elephants don’t make for success at Sellafield.”

The British government and the Nuclear Decommissioning Authority, which runs the plant on behalf of taxpayers, have never revealed the losses it has incurred.  The government has no policy on what to do with the mountain of unwanted plutonium and uranium.

For accounting purposes, Forwood says, it is still counted as an asset, when in reality it is simply nuclear waste. The nuclear industry’s hopes of saving the planet from climate change by recycling reactor fuel have, he says, been “a complete commercial and technical failure.” − Climate News Network

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Cut carbon now to avoid climate tipping points

Cut carbon now to avoid climate tipping points

The price to be paid for not cutting greenhouse gas emissions could push the planetary climate system closer to irreversible “tipping points”.

LONDON, 3 April, 2015 – An international team of scientists has tried a new approach to addressing the complex argument about the costs of climate change – and, once again, the prediction is that the costs of inaction will be so much greater than paying the bills now.

The researchers − from the UK, Switzerland and the US − conclude that policy-makers must apply the brakes and put a high price on carbon emissions “before it is too late”.

Much of the argument on this issue revolves around the perceived cost of carbon emissions and any tax that should be imposed on fossil fuel use. Social scientists and economists and climate modellers have tried a number of approaches.

One group tried to work out the interval between the burning of fossil fuels and the consequent greenhouse warming, and concluded it could be as little as 10 years.

Other groups have separately tried to calculate the true cost of emitted carbon dioxide. The US government works on the basis of $37 in social costs per tonne emitted, but two US scientists proposed that the true cost in future health and habitat losses was probably six times higher.

“The additional carbon tax that our model recommends can be thought of as an insurance premium levied on society”

And yet another researcher began to examine the costs of petrol, or coal, or methane gas if the long-term economic damage and health costs were factored in, and concluded that these made “expensive” renewables cheap by comparison.

Now researchers from the universities of Exeter in the UK, Zurich in Switzerland and Chicago and Stanford in the US report in Nature Climate Change that they considered the risk that emitted greenhouse gases from fossil fuels would push the planetary climate system closer to what climate scientists call “tipping points.”

These are outcomes that would irreversibly change regional climate patterns, disrupt agriculture, precipitate greater flooding in some places, more sustained droughts in others, and accelerate sea level rise.

And, once again, they find that governments have underestimated the price to be paid by society for carbon dioxide emissions from fossil fuels.

“We are calling on policy-makers to respond to the prospect of triggering future climate tipping points by applying the brakes now and putting a high price on carbon emissions before it is too late,” says one of the authors, Tim Lenton, professor of climate change and earth system science at the University of Exeter.

“The additional carbon tax that our model recommends can be thought of as an insurance premium levied on society to delay irreversible changes in the future.”

The researchers selected five potential tipping points − all of which have separately been in the news recently. They relate to:

The researchers say their act-now, save-future-costs model not only demonstrates the dangers of underestimating the cost of future climate change, but is the first one to emerge from a purely market-based approach. The considerations do not have to be based on moral judgements about sustainability and the wellbeing of future generations. – Climate News Network

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