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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Familiar fish find northern seas too warm for comfort

Familiar fish find northern seas too warm for comfort

Fish accustomed to shallow northern waters will search in vain for cooler depths as climate change warms the seas where they thrive.

LONDON, 18 April, 2015 – Some of Northern Europe’s favourite suppers may be about to swim off the menu altogether. Global warming could change the future catch, according to new research.

British scientists report in the journal Nature Climate Change that popular species such as haddock, lemon sole and plaice could become less common as the climate changes and the North Sea warms.

The North Sea is relatively shallow – during the height of the Ice Age, much of the sea bed was dry land – which means that fish that would otherwise find deeper waters to keep cool have nowhere to go.

The North Atlantic is warming fast. The mean annual North Sea surface temperatures have increased by 1.3°C in the past 30 years. This is four times faster than the global average. But fish evolved to make a living in the temperatures that suit them best, and the evidence is that the North Sea is increasingly host to species that were once characteristic of the Mediterranean.

Changing abundance

Fishing is big business: landings in 2007 in the region reached $1.2 billion, and accordingly the ecology of the North Sea has been intensively monitored. Cold-adapted landings have halved in the last 30 years, but landings of warm-adapted species have increased 2.5 times. With a baseline of very detailed data from the past, the researchers were able to use computer models to build up a picture of things to come in northern waters.

And the result is this: the demersal or bottom-feeding fish that were the basis of fish-and-chip suppers from Cornwall in the UK to northern Norway are likely to dwindle over the next 50 years. Many of them cannot move north to get away from the heat, because there is no suitable habitat, and they can’t go deeper, because there isn’t any depth. So the abundance of species will change with time.

“Our study suggests that we will see proportionately less of some of the species we eat most of as they struggle to cope with warming conditions in the North Sea,” said Louise Rutterford of Exeter University, the first author.

Squeezed out

“We provide new insight into how important local depths and associated habitats are to these commercial species. It’s something that is not always captured in existing models that predict future fish distributions.”

Other studies have found that fish in many regions are changing to new latitudes as climates change in response to greenhouse gas emissions from fossil fuel combustion. The same man-made global warming has brought a greater number of sardines, for instance, to northern waters, and in the US fishermen have had to sail ever further north to pursue the black bass. There has even been a warning that the retreat of the Arctic ice means that Atlantic halibut could actually migrate into the North Pacific.

So the latest message is confirmation of an increasingly familiar finding. “We will see a real changing of the guard in the next few decades,” said Steve Simpson, a marine biologist at Exeter, and another of the authors.

“Our models predict cold water species will be squeezed out with warmer water fish likely to take their place. For sustainable UK fisheries, we need to move from haddock and chips and look to southern Europe for our gastronomic inspiration.” – 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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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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Investors chip in as renewables rise towards record level

Investors chip in as renewables rise towards record level

Climate-friendly boost for global energy mix as scientists say solar power alone could now meet the needs of California five times over.

LONDON, 12 April, 2015 − Carbon dioxide levels might be soaring, and governments might be slow to reduce fossil fuel emissions and contain climate change − but the smart money could nevertheless be going into renewable sources such as wind and solar power.

The United Nations Environment Programme (UNEP) says green energy investments rose by 17% in 2014 to reach a total of $270bn − the first annual increase in three years, and just 3% behind the all-time record set in 2011 of $279bn.

In 2014, renewable energies added 103 gigawatts to global capacity. This is roughly equal to the output of all 158 nuclear power reactors in the US.

Wind, solar, biomass, waste-to-power, geothermal, small hydro and marine power contributed an estimated 9.1% of world electricity generation in 2014. This also represents a notional saving in carbon dioxide emissions of 1.3 gigatonnes, which is about twice what pours from the exhausts of the world airlines.

Markets mature

“Once again in 2014, renewable made up nearly half the power capacity added worldwide,” said Achim Steiner, executive director of UNEP.

“These climate-friendly energy technologies are now an indispensable component of the global energy mix and their importance will only increase as markets mature, technology prices continue to fall and the need to rein in carbon emissions becomes ever more urgent.”

But, according to scientists backed by the Carnegie Institution, there is much more that could be done. A team led by Earth system scientists Rebecca Hernandez, now of the University of California Berkeley, reported in Nature Climate Change that solar energy alone could meet the demands of the state of California in the US up to five times over.

Solar power systems based on photovoltaics could generate up to 15,000 terawatts of energy a year. And mirror-driven concentrating systems could add another 6,000 terawatt hours.

California – now in the grip of a calamitous drought that has been tentatively linked to climate change triggered by human investment in fossil fuels – is the most populous state in the US. The researchers calculated that more than 27,000 square kilometres of land would be fit for photovoltaic solar construction, and more than 6,000 square kilometres for concentrating solar power.

“Their importance will only increase as markets mature, technology prices continue to fall
and the need to rein in carbon emissions becomes ever more urgent”

But there is a darker side to the story of renewable energy. On the other side of the Rocky Mountains, scientists have been working on the much more complex carbon budget of biofuels, which deliver energy in liquid form.

They count as renewable energy because, although they emit carbon dioxide when burned, they do not, overall, add to the levels of greenhouse gases in the atmosphere. That is because biofuel crops take carbon dioxide from the air to grow their tissues for conversion to fuel, and return the gas through engine exhausts.

But there have been persistent worries. One is that the conversion of food to fuel may not be the most efficient use of cropland.

Destroy ecosystems

The approach remains carbon neutral, as long as farmers exploit existing cropland. But the danger is that farmers might plough up existing grassland, destroy ecosystems, and release ancient stored soil carbon to the atmosphere, to make global warming worse.

Environmental scientist Tyler Lark and colleagues at the University of Wisconsin-Madison report in Environmental Research Letters that, between 2008 and 2012, US farmers ploughed seven million acres of new land for corn and soy for conversion to biofuels intended as renewable energy for motor transport.

In the course of doing so, they could have emitted as much carbon to the atmosphere as 34 coal-burning power stations in one year – or 28 million new cars on the road.

Nearly a quarter of the land converted came from long-standing prairies and ranges, much of it within the Central Plains, from North Dakota to Texas. And much of this was planted with corn intended for conversion to biofuels.

“It mimics the extreme land-use change that led to the Dust Bowl in the 1930s,” Lark says. “We could be, in a sense, ploughing up prairies with each mile we drive.” – 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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Canada will lose many glaciers as climate warms

Canada will lose many glaciers as climate warms

Climate change could cause many glaciers in western Canada to start to disappear by 2040, affecting people and places that depend on their water.

LONDON, 10 April, 2015 − As the world warms, many of the great frozen rivers of Canada will not just retreat, but could vanish altogether.

New research suggests that maritime glaciers in the far northwest might survive, but more than two-thirds of Canada’s existing glaciers in British Columbia and Alberta could be lost altogether by 2100.

Garry Clarke, a glaciologist at the University of British Columbia in Vancouver, says: “Soon our mountains could look like those in Colorado or California, and you don’t see much ice in those landscapes.”

The consequences for the forests, grasslands, animals and communities that depend on glacial meltwater could be serious. The disappearance of the glaciers will also create problems for Canada’s hydroelectric industry, for agriculture and grazing, for the mining industry, for the salmon fishery, and for tourism.

Professor Clarke and his colleagues report in Nature Geoscience that they devised a model – a high-resolution computer simulation – of the glaciers of western Canada that explicitly mimicked glacial flow. Then they tested it with a range of scenarios for climate change, driven by human combustion of fossil fuels and rising atmospheric carbon dioxide levels in the last two centuries.

“Once the glaciers are gone, the streams will be a lot warmer and this will hugely change freshwater habitat”

There are more than 17,000 glaciers in British Columbia and Alberta, covering more than 26,000 square kilometres of the two provinces, and holding an estimated 2,980 cubic kilometres of ice. This puts western Canada as more glaciated than the Himalayas (which have less than 23,000 sq kms of glacier): the entire continent of South America has only 31,000 sq kms of glacier.

The researchers found that maritime glaciers in the northwest would endure, in a diminished state. But overall, the volume of the glaciers in western Canada would shrink by 70%, give or take 10%.

Right now glaciers, most of them between 100 and 200 metres thick, are thinning at a rate of about a metre a year. The peak flow of meltwater would most likely occur between 2020 and 2040. Thereafter, the rivers would be in decline.

Potential sea level rise as a consequence of this, the scientists say, would be “modest” at around 6mm, but the consequences for that part of Canada would be substantial.

The Columbia River, which flows from the interior to the Pacific coast of Washington and Oregon, yields the largest hydroelectric production of any river in North America. And the impact on freshwater ecosystems could be considerable.

“These glaciers act as a thermostat for freshwater systems,” said Professor Clarke. “Once the glaciers are gone, the streams will be a lot warmer and this will hugely change freshwater habitat. We could see some unpleasant surprises in terms of salmon productivity.” – 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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