The world we are shaping is feeling the strain

The world we are shaping is feeling the strain

The world risks being destabilised by human activity, scientists report, most of it the work of a rich minority of us.

LONDON, 16 January, 2015 – Humans are now the chief drivers of change in the planet’s physical, chemical, biological and economic systems according to new research in a series of journals. And the humans most implicated in this change so far are the 18% of mankind that accounts for 74% of gross domestic productivity.

And the indicators of this change – dubbed the “planetary dashboard” – are 24 sets of measurements that record the acceleration of the carbon cycle, land use, fisheries, telecommunications, energy consumption, population, economic growth, transport, water use and many other interlinked aspects of what scientists think of as the Earth System.

Although these indicators chart change since the start of the Industrial Revolution in the 18th century, the most dramatic acceleration – the scientists call it the Great Acceleration – seems to have begun in 1950. Some researchers would like to set that decade as the start of a new geological epoch, the Anthropocene, from Anthropos, the ancient Greek word for mankind.

On the eve of this year’s World Economic Forum in Davos, Switzerland, a team of scientists led by Will Steffen of the Stockholm Resilience Centre at Stockholm University and the Australian National University report in the journal Science that the world has now crossed four of nine planetary boundaries within which humans could have hoped for a safe operating space.

The four boundaries are climate change, land system change, alterations to the biogeochemical cycle that follow phosphorus and nitrogen fertiliser use, and the loss of a condition called “biosphere integrity”.

Past their peak

The scientists judge that these boundary-crossing advances mean that both present and future human society are in danger of destabilising the Earth System, a complex interaction of land, sea, atmosphere, the icecaps, natural living things and humans themselves.

“Transgressing a boundary increases the risk that human activities could inadvertently drive the Earth System into a much less hospitable state, damaging efforts to reduce poverty and leading to deterioration of human wellbeing in many parts of the world, including wealthy countries”, said Professor Steffen. “In this new analysis we have improved the quantification of where these risks lie.”

The Science article is supported by separate studies of global change. These were backed by the International Geosphere-Biosphere Programme, also headquartered in Stockholm, which publishes an analysis in the journal the Anthropocene Review.

Meanwhile a team of European scientists warn in the journal Ecology and Society that out of 20 renewable resources (among them the maize, wheat, rice, soya, fish, meat, milk and eggs that feed the world) 18 have already passed their peak production.

And a separate team led by scientists from Leicester University in Britain has even tried to pinpoint the day on which the Anthropocene era may be said to have commenced. In yet another journal, the Quaternary International, they nominate 16 July, 1945: the day of the world’s first nuclear test.

Unequal world

This flurry of research and review is of course timed to help world leaders at Davos concentrate on the longer-term problems of climate change, environmental degradation, and food security, in addition to immediate problems of economic stagnation, poverty, conflict and so on. But these immediate challenges may not be separable from the longer-term ones. To ram the message home, the authors will present their findings at seven seminars in Davos.

In the Anthropocene Review, Professor Steffen and his co-authors consider not just the strains on the planet’s resources that threaten stability, but also that section of humanity that is responsible for most of the strain.

Although the human burden of population has soared from 2.5bn to more than 7bn in one lifetime, in 2010, the scientists say, the OECD countries that are home to 18% of the world’s population accounted for 74% of global gross domestic product, so most of the human imprint on the Earth System comes from the world represented by the OECD.

This, they say, points to the profound scale of global inequality, which means that the benefits of the so-called Great Acceleration in consumption of resources are unevenly distributed, and this in turn confounds efforts to deal with the impact of this assault on the planetary machinery. Humans have always altered their environment, they concede, but now the scale of the alteration is, in its rate and magnitude, without precedent.

“Furthermore, by treating ‘humans’ as a single, monolithic whole, it ignores the fact that the Great Acceleration has, until very recently, been almost entirely driven by a small fraction of the human population, those in developed countries”, they say.

“…What surprised us was the timing. Almost all graphs show the same pattern. The most dramatic shifts have occurred since 1950”

The IGBP-Stockholm Resilience Centre co-operation first identified their 24 “indicators” of planetary change in 2004, and the latest research is a revisitation. In 2009, researchers identified nine global priorities linked to human impacts on the environment, and identified two, ­ climate change and the integrity of the biosphere, ­ that were vital to the human condition. Any alteration to either could drive the Earth System into a new state, they said.

In fact, since then, greenhouse gas emissions have continued to rise, and accordingly global average temperatures have steadily increased, along with sea levels. At the same time, habitat destruction, pollution and hunting and fishing have begun to drive species to extinction at an accelerating rate.

Almost all the charts that make up the planetary dashboard now show steep acceleration: fisheries, one of the indicators that seems to have levelled off, has probably done so only because humans may have already exhausted some of the ocean’s resources.

“It is difficult to over-estimate the scale and speed of change. In a single human lifetime humanity has become a planetary-scale geological force”, said Prof Steffen. “When we first aggregated these datasets we expected to see major changes, but what surprised us was the timing. Almost all graphs show the same pattern.

“The most dramatic shifts have occurred since 1950. We can say that 1950 was the start of the Great Acceleration. After 1950 you can see that major Earth System changes became directly linked to changes related to the global economic system. This is a new phenomenon and indicates that humanity has a new responsibility at a global level for the planet.” ­­­­–­ Climate News Network

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Peat bog fires are burning issue in climate calculations

Peat bog fires are burning issue in climate calculations

Human exploitation and drainage of carbon-rich peatlands has led to some of the biggest fires on Earth – another factor fanning the flames of global warming.

LONDON, 10 January, 2015 − The greatest concentrations of the world’s soil carbon have been pinpointed by researchers − and much of it is a dangerously flammable addition to climate change concerns.

An international scientific survey of peat bogs has calculated that they contain more carbon than all the world’s forests, heaths and grasslands together − and perhaps as much as the planet’s atmosphere. Since peat can smoulder underground for years, it is another potential factor in global warming calculations.

Peat is simply leaf litter that never completely decayed. Ancient peatlands become distinctive ecosystems and, in some places, an economic resource.

Soil carbon

Merritt Turetsky, an ecosystem ecologist at the University of Guelph, Ontario, and colleagues report in Nature Geoscience that peatlands cover between only 2% and 3% of the planet’s land surface, but store 25% of the planet’s soil carbon.

In the high latitudes of the northern hemisphere, they cover about 4 million sq km and store between 500 and 600 billion tonnes of carbon. In the tropics – and especially in south-east Asia – they cover about 400,000 sq km and store 100 billion tonnes of carbon. The entire pool of atmospheric carbon, in the form of carbon dioxide, adds up to about 850 billion tonnes.

In its pristine condition, a peat bog is unlikely to burn: the peat exists because vegetation doesn’t decay normally in water.

“Peat fires . . . lack the drama of flames, but they produce a lot of smoke”

But, over thousands of years, humans have drained the peat bogs, exploited them for fuel, and even used peat as a gardening mulch. Dry peat burns easily, and some of the largest fires on Earth are now in the drained peatlands.

“When people think of a forest fire, they probably think of flames licking up into treetops, and animals trying to escape,” Dr Turetsky says. “But peat fires tend to be creeping ground fires. They can burn for days or weeks, even under relatively wet conditions. They lack the drama of flames, but they produce a lot of smoke.”

The research by Canadian, British, Dutch and US scientists is part of a wider global attempt to understand the carbon cycle.

Global warming happens because more carbon goes into the atmosphere as carbon dioxide than plants in the oceans and on land can absorb. So it makes sense to work out in fine detail where the carbon comes from, and how it is soaked up by living things.

Enduring hazard

Peat fires are an enduring hazard, and a local threat to human health. But in a warming world, in which the human population has trebled in one lifetime, the peatlands are drying out, and could fan the flames of climate change.

Once started, peat fires are hard to stop. Fire in the treetops can race across the forest at 10 kilometres an hour, while smouldering peat can take a week to travel half a metre. But both can happen at once, the scientists report.

“The tropical peatlands of South-east Asia are a clear demonstration of how human activity can alter the natural relationships between ecosystems and fire,” said Susan Page, professor of physical geography at the University of Leicester, UK, and a co-author of the latest report.

In a Nature study in 2002, she calculated that a dramatic and sustained forest fire in Indonesia in 1997 may have sent 2.5 billion tonnes of carbon into the atmosphere – a figure that could have added up to 40% of all the emissions from all the fossil fuel burning that year.

“Tropical peatlands are highly resistant to natural fires, but in recent decades humans have drained peatlands for plantation agriculture,” she said. “People cause the deep layers of peat to dry out, and also greatly increase the number of fire ignitions. It’s a double threat.” – Climate News Network

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Underworld holds vital clues to carbon cycle puzzle

Underworld holds vital clues to carbon cycle puzzle

New research confirms that what goes on out of sight in the earth beneath our feet determines whether carbon is stored or released into the atmosphere.

LONDON, 7 January, 2015 − More trees and more vigorous vegetation growth may not soak up atmospheric carbon, according to new research.

Instead, more lusty tree roots could goad the soil microbe population into releasing as carbon dioxide so much more old carbon stored in the soil. And since the planet’s store of soil carbon is at least twice the quantity locked in the vegetation and the atmosphere, this could in turn accelerate global warming.

This is yet another example of what engineers call positive feedback, but the important word here is “could”. The question remains open.

Benjamin Sulman − a biologist at Indiana University, but then of the Princeton University Environmental Institute in the US − and colleagues report in Nature Climate Change that they have developed a new computer model to examine what really happens, on a global scale, when plants colonise the soil and start taking in moisture and carbon from the atmosphere.

Unexplored economy

The topsoil – the fertile mix of loam, rock dust, minerals, partly decomposed wood, straw and leaf litter, fungi, bacteria, invertebrates and moisture from which all of terrestrial life derives its nourishment – remains one of the great unexplored economies of the planet.

The puzzle is this: plants draw carbon dioxide from the atmosphere to build up their tissues, but some of this tissue decomposes and returns to the air, while some stays in the soil, locked away from the atmosphere.

Deforestation is well established as a major factor in the greenhouse gas budget, so more forests would be a good thing. More carbon dioxide should mean more vigorous growth, so more tree growth should start to reduce the atmospheric carbon levels.

“You should not count on getting more carbon storage in the soil just because tree growth is increasing”

But as the Princeton team have confirmed once again, it’s not so simple. “You should not count on getting more carbon storage in the soil just because tree growth is increasing,” said Dr Sulman.

“The goal was to take a very simple model and add some of the important missing processes. The main interactions between roots and soil are important and shouldn’t be ignored.

“Root growth and activity are such important drivers of what goes on in the soil, and knowing what the roots are doing could be an important part of understanding what the soil will be doing.”

Mechanics of life

Like all such research, the study offers a measure of how little we know of the mechanics of life, atmosphere, ocean and rock − and, in particular, the carbon cycle. Clearly, some of the most important things happen underfoot, literally buried from sight.

One study, published recently in Nature journal, tried to make an audit of the richness of life in the soil: there could be up to 9,000 different species of bacteria in a cubic centimetre, more than 200 different kinds of fungi in a gram of soil, and the total numbers of these microbes would add up to billions.

Add to this a dizzying variety of tiny invertebrates and other life forms, all playing a part in making growth happen and in disposing of the detritus, and the puzzle becomes even more perplexing.

Another study, also published in Nature, tried to work out how these rich and extraordinary microbial communities would respond to warmer temperatures.

The conclusion was that the soil would “breathe” faster, which means a greater traffic in carbon, especially in those high latitude places where there was a lot of stored carbon − in particular, the Arctic permafrost.

Disconcerting effect

Since the soil microbes normally release at least 60 billion metric tonnes of carbon back to the atmosphere each year as carbon dioxide, any increase could have disconcerting consequences.

So researchers have repeatedly tried to make sense of the subterranean carbon cycle. They have established that fungi, in particular, play a role in the continuous traffic of energy and carbon that drives the plant world.

They have evidence that the soils may not store carbon as efficiently as they had once assumed, and that, to slow global warming, it may not be enough to just save the trees. Scientists must also consider the roles of such areas as grasslands, savannah and wetlands.

The message from all this research, and from the latest Princeton study, is that we may have mapped the planet Earth with exquisite precision, but we still don’t know much about the earth beneath our feet. There’s a whole new world down there. – Climate News Network

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Tropical forests may be giving climate extra help

Tropical forests may be giving climate extra help

New research indicates that the role of the world’s tropical forests in removing carbon dioxide from the atmosphere may have been underestimated.

LONDON, 4 January, 2015 − Scientists in the US say the world’s tropical forests may be making a much larger contribution to slowing climate change than many of their colleagues have previously recognised.

A new study − led by the space agency NASA and the US National Center for Atmospheric Research, and published in the Proceedings of the National Academy of Sciences − suggests that the forests are absorbing far more carbon dioxide from human sources than they are given credit for.

It estimates that the forests are absorbing 1.4 billion tonnes of human-derived CO2 − a sizeable slice of the total global absorption of 2.5 billion tonnes.

If the tropical forests are left undisturbed, the trees should be able to go on reducing the rate of global warming by removing COfrom the atmosphere.

Damaging effect

Conversely, continuing destruction of the forests may prove to have an even more damaging effect on countering the rising rate of CO2 emissions, because if the rate of absorption slows down, the rate of global warming will accelerate.

Lead author David Schimel, a research scientist at the NASA Jet Propulsion Laboratory, says: “This is good news, because uptake in northern forests may already be slowing, while tropical forests may continue to take up carbon for many years.”

The question of which type of forest absorbs more carbon “is not just an accounting curiosity”, says one of the paper’s co-authors, Britton Stephens, a scientist at the  National Center for Atmospheric Research’s Earth Observing Laboratory in Boulder, Colarado.

“It has big implications for our understanding of whether global terrestrial ecosystems might continue to offset our carbon dioxide emissions or might begin to exacerbate climate change.”

“It is incredible that all these . . . independent data sources start to converge on an answer”

Forests and other land vegetation currently remove up to 30% of human CO2 emissions from the atmosphere by absorbing the gas during photosynthesis.

The new study is the first to devise a way to make direct comparisons of CO2 uptake estimates from many sources at different scales, including computer models of ecosystem processes, atmospheric models used to deduce the sources of today’s concentrations (called atmospheric inverse models), satellite images, and data from routine and experimental forest plots.

Ecosystem model

The researchers reconciled these analyses and assessed the accuracy of the inverse models based on how well they reproduced independent, airborne and ground-based measurements. They obtained their new estimate of the tropical carbon absorption from the weighted average of atmospheric, ecosystem model and ground-based data.

“Until our analysis, no one had successfully completed a global reconciliation of information about carbon dioxide effects from the atmospheric, forestry, and modeling communities,” says the report’s co-author, Joshua Fisher, a researcher at the NASA Jet Propulsion Laboratory. “It is incredible that all these different types of independent data sources start to converge on an answer.”

As human-caused emissions add more CO2 to the atmosphere, forests worldwide are using it to grow faster, reducing the amount that stays airborne. This effect is called carbon dioxide fertilisation.

But climate change also decreases the amount of water available in some regions and warms the Earth, causing more frequent droughts and larger wildfires.

For about 25 years, most atmospheric inverse models have been showing that mid-latitude forests in the northern hemisphere absorb more CO2 than tropical forests. This result was based on the prevailing understanding of global air flows and limited data suggesting that deforestation was causing tropical forests to release more CO2 than they were absorbing.

Measurements of CO2

In the mid-2000s, Britton Stephens used measurements of CO2 made from aircraft to show that many atmospheric inverse models were not correctly representing flows of the gas in the air above ground level. Models that matched the aircraft measurements better showed more carbon absorption in the tropical forests.

Dr Schimel says the new paper reconciles results at every scale − from the pores of a single leaf, where photosynthesis takes place, to the whole Earth, as air moves carbon dioxide around the globe.

There is still considerable uncertainty about the part played by the tropical forests in moderating the climate. One study, for example, found that trees in the forests of Borneo absorbed much more CO2 than those in Amazonia. Another found that the southern Amazon forest was drying out far faster than had been projected.

Meanwhile, the rate of deforestation continues to increase in many vulnerable areas.

In June 2014, it was reported that Indonesia’s clearance of its forests was, for the first time, happening faster than in Brazil. Three months later, the Brazilian NGO Imazon said the rate of forest loss in the country’s Amazon region had risen by 290% in the past 12 months. − Climate News Network

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Scientists track natural responses to climate change

Scientists track natural responses to climate change

Researchers in the US have identified a wide range of impacts – human and natural – that global warming has on fish, forests, birds and wildflowers.

LONDON, 31 December, 2014 − Lumberjacks are selecting different trees, US fishermen are sailing further north to catch black sea bass, desert birds are nesting later in California and Arizona, and one kind of wildflower is changing shape in the Rocky Mountains − and all in response to climate change, according to new research.

None of these responses is simple, or necessarily ominous, and global warming is not the only factor at work. But all are nevertheless examples of adaptation to − so far – very modest changes in temperature.

Adena Rissman and Chad Rittenhouse, of the University of Wisconsin-Madison, report in the Journal of Environmental Management that they looked at weather records and logging data and found that, since 1948, the winter interval during which ground is firmly frozen has declined by an average of two to three weeks.

Hard winters are the logger’s friend as the ground can support heavy machinery, whereas muddy soils can make tracks impassable. So, over the decades, foresters have harvested more and more red pine and jack pine − species that flourish in sandy, well-drained soil more accessible to trucks, tractors and chainsaws.

Significant decline

“We wanted to know how weather affects our ability to support sustainable working forests,” says Dr Rissman, assistant professor of human dimensions of ecosystem management. “We found a significant decline in the duration of frozen ground over the past 65 years and, at the same time, a significant shift in the species being harvested.”

Such changes in selection tend to affect ecosystems – on land or at sea.

Scientists at the Northeast Fisheries Science Centre in the US report in the ICES Journal of Marine Science that they looked at trawl survey data collected between 1972 and 2008 to analyse variations in abundance of black sea bass, scup, and summer and winter flounder. All had shown “significant poleward shifts” in at least one season.

“We demonstrated how a combination of fishing and climate can influence the distribution of marine fish”

The bass and scup were responding to changes in temperature. The summer flounder were more likely to be responding to a decrease in fishing pressure − that is, the species could recolonise former habitat. There was no change in the distribution in the southern New England/Mid Atlantic Bight stock of winter flounder.

“Using these data, we demonstrated how a combination of fishing and climate can influence the distribution of marine fish,” said lead author Richard Bell, research associate at the US National Oceanic and Atmospheric Administration fisheries service laboratory at Narrangansett.“It is not one or the other.”

Meanwhile, in the arid American southwest’s Sonora Desert, all 13 desert bird species have tended to delay nesting by two weeks or more, as a response to severe drought.

Delays in nesting

This makes survival a problem for the birds as their young are more vulnerable to nest predators and parasites. Some species forego breeding entirely during an extreme drought. Even without global warming, droughts are an enduring fact of life in the region. But ecologists point out that climate models predict a greater frequency of droughts, which could lead to even more delays in nesting.

“These responses are predicted to become more frequent and extreme, due to climate change, causing us to question how desert birds will persist in the long term,” Chris McCreedy, a desert ecologist at Point Blue Conservation Science, reports in The Auk, the American Ornithologists’ Union journal.

The hardy Rocky Mountain mustard plant Image: USDA via Wikimedia Commons

The hardy Rocky Mountain mustard plant
Image: USDA via Wikimedia Commonse

At least one species has responded to climate change by altering not just its life cycle but its shape.

Students at Dartmouth College in New Hampshire and the University of South Carolina report in Global Change Biology that the Rocky Mountain mustard plant (Boechera stricta) offers an example of what biologists call “phenotypic plasticity”.

This means that it doesn’t evolve to meet climate change − it just looks different under different conditions. It changes according to whether the conditions are hot and dry, or cold and wet. In experiments that simulated future climate change, it also flowered seven days earlier.

This little ready-for-anything brassica plant seemed able to respond differently according to whether or not there was snow around it. Or, as the researchers put it: “Extensive plasticity could buffer against immediate fitness declines due to changing climates.” – Climate News Network

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Professors tell greens to accept nuclear power

Professors tell greens to accept nuclear power

Academics argue that nuclear power is essential to save the planet from climate change, but critics say they seem to have forgotten the danger of a nuclear winter.

LONDON, 26 December, 2014 − Seventy-five professors from the world’s leading universities have signed a letter urging environmentalists to re-think their attitude to nuclear power as a way to save the planet from climate change and preserve its animals, plants and fish.

Ironically, it is two Australian academics who came up with the research. They come from a country whose government has repudiated the Kyoto Protocol, reversed measures to cut climate change, is one of the world’s biggest coal exporters, and has no nuclear power. Australia has just recorded the hottest spring since records began 100 years ago.

The two professors are Barry W. Brook, Chair of Environmental Sustainability at the University of Tasmania, and Corey J.A. Bradshaw, Sir Hubert Wilkins Chair of Climate Change at the University of Adelaide’s Environment Institute. Their backers include many leading experts on ecology, biodiversity, evolution and geography from the US, UK, China and India.

The letter is significant because previous pleas for a role for nuclear power have mostly come from physics professors, who could reasonably be said to love the technology for its own sake.

But this group has no stake in nuclear power, and their argument is based purely on the need to save the planet and its species from overheating and excess use of valuable land for renewables. Professors Brook and Bradshaw have had a paper published in the magazine Conservation Biology, in which they evaluated all possible forms of energy generation. Wind and nuclear power had the highest “benefit-to-cost ratio”.

“…we entreat the conservation and environmental community to weigh up the pros and cons of different energy sources…”

The letter urges environmentalists to read the paper, and says the two professors “provide strong evidence for the need to accept a substantial role for advanced nuclear power systems with complete fuel recycling − as part of a range of sustainable energy technologies that also includes appropriate use of renewables, energy storage and energy efficiency.

“This multi-pronged strategy for sustainable energy could also be more cost-effective and spare more land for biodiversity, as well as reduce non-carbon pollution (aerosols, heavy metals).

“Given the historical antagonism towards nuclear energy amongst the environmental community, we accept that this stands as a controversial position.

“However, much as leading climate scientists have recently advocated the development of safe, next-generation nuclear energy systems to combat global climate change, we entreat the conservation and environmental community to weigh up the pros and cons of different energy sources, using objective evidence and pragmatic trade-offs, rather than simply relying on idealistic perceptions of what is ‘green’.

“Although renewable energy sources like wind and solar will likely make increasing contributions to future energy production, these technology options face real-world problems of scalability, cost, material and land use, meaning that it is too risky to rely on them as the only alternatives to fossil fuels.

Conflict risk

“Nuclear power − being by far the most compact and energy-dense of sources − could also make a major, and perhaps leading, contribution. As scientists, we declare that an evidence-based approach to future energy production is an essential component of securing biodiversity’s future and cannot be ignored. It is time that conservationists make their voices heard in this policy arena.”

The letter has attracted a wide variety of comments. Some are supportive, but others say that the professors have ignored one of the greatest threats to the planet – a nuclear war.

Dr Jim Green, writing in the Ecologist magazine, makes the point that nuclear power and nuclear proliferation go hand in hand:  “Even a modest exchange of nuclear warheads could profoundly affect biodiversity, and large scale nuclear war certainly would.”

Dr Green also attacks the paper for endorsing fast breeder reactor technology as the solution to climate change. He says that the “fast reactor techno-utopia presented by Brook and Bradshaw is theoretically attractive”, but has already been tried unsuccessfully, and cannot be made to work in the real world. – Climate News Network

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Beavers damned for increasing threat from methane

Beavers damned for increasing threat from methane

The growth of the world’s beaver population to more than 10 million has led to a big increase in one of the main greenhouse gases that cause climate change.

LONDON, 21 December, 2014 − For a picture of industrious innocence, beavers are hard to beat. Yet they now find themselves facing a grave charge: they are, it seems, responsible for increasing greenhouse gas emissions.

The problem, Canadian scientists say, lies in the shallow ponds that form behind the dams the beavers build. The ponds are essential to the animals’ way of life. Unfortunately, they’re also good places for generating methane.

Methane is a powerful greenhouse gas, and in the short term it does much more damage than the far more abundant carbon dioxide. There is now international agreement that methane is 34 times more potent than CO2 over a century, but 84 times more over a much shorter timespan – just 20 years. And two decades can be crucial in trying to slow the rate of climate change.

Trapping limited

Colin J. Whitfield, of the University of Saskatchewan, led a study − published in the journal AMBIO − from which he estimated that beaver numbers in Eurasia and the Americas have grown so much that the methane emissions the ponds produce are now 200 times higher than in 1900.

Between the 16th and the 19th centuries, the fur trade nearly led to the beavers’ extinction worldwide. After trapping was limited and they were re-introduced to their natural ranges, the number of North American (Castor canadensis) and Eurasian (Castor fiber) beavers began to grow. The North American beaver has also been introduced to parts of Eurasia and South America.

“This suggests that the contribution of beaver activity to global methane emissions may continue to grow”

Beavers build dams in rivers to create standing open-water ponds and wetlands. The ponds are usually shallow, with dams seldom more than 1.5 metres high. The study found that carbon builds up in the oxygen-poor pond bottoms, and methane is then generated. Unable to dissolve adequately in the shallow water, it is released into the atmosphere.

The team estimated the size of the current global beaver population and determined the area covered by beaver ponds. They found that global beaver numbers have grown to over 10 million, damming more than 42,000 sq kms of aquatic pond areas, bordered by over 200,000 kms of shoreline habitat.

At the end of the 20th century, they say, beavers contributed up to 0.80 teragrams (or 800 million kilograms) of methane to the atmosphere annually. This is about 15% of the input from wild cud-chewing animals such as deer or antelopes.

“Continued range expansion, coupled with changes in population and pond densities, may dramatically increase the amount of water impounded by the beaver,” Whitfield says.

“This, in combination with anticipated increases in surface water temperatures, and likely effects on rates of methanogenesis, suggests that the contribution of beaver activity to global methane emissions may continue to grow.”

Copious amounts

Beavers are not alone in unwittingly worsening climate change. Ruminants − animals that chew the cud − emit copious amounts of methane, prompting concerns about the impacts on the atmosphere of an increasingly meat-based human diet.

Now comes news that another species may have to step up and accept some of the blame for a warming world.

Scientists from Woods Hole Research Center, in the US, told the American Geophysical Union fall meeting in San Francisco that Arctic ground squirrels may be playing a greater role in climate change than previously thought.

They say the animals are hastening the release of greenhouse gases from the permafrost, accelerating an existing positive feedback that means the warming temperatures help the frozen soil to thaw and emit still more greenhouse gas. − Climate News Network

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Loss of rainforests is double whammy threat to climate

Loss of rainforests is double whammy threat to climate

New research spells out the devastating impacts that complete destruction of tropical forests would have on global temperatures, weather patterns and agriculture.

LONDON, 20 December, 2014 − Tropical rainforests do more than just soak up carbon dioxide and renew atmospheric oxygen, they affect the weather in the rest of the world as well. And if the Amazon rainforest disappeared, the US Midwest could begin to dry up during the growing season.

In what is claimed as the most comprehensive analysis to date, US researchers report in Nature Climate Change that they used climate models to test the consequences of the complete devastation of the tropical rainforests.

They found that wholesale felling and clearing of the forests in Amazonia, Africa and South-east Asia would have consequences that extended far beyond the tropics, and could affect agriculture in North America, Europe and Asia.

“Tropical deforestation delivers a double whammy to the climate – and to farmers,” says Deborah Lawrence, an environmental scientist at the University of Virginia.

Rainfall patterns

“Most people know that climate change is a dangerous global problem, and that it’s caused by pumping carbon into the atmosphere. But it turns out that removing forests alters moisture and air flow, leading to changes – from fluctuating rainfall patterns to rises in temperatures – that are just as hazardous, and happen right away.

“The impacts go beyond the tropics – the UK and Hawaii could see an increase in rainfall, while the US Midwest and Southern France could see a decline.”

Although the research is based on computer simulations, there is already evidence that the disappearance of the tropical forests has begun to affect regional climates. The dry season in Thailand has become drier, and the rainy season in the Amazon has been delayed by up to two weeks, in those tracts that have been cleared. In the forested regions, the rains still arrive on time.

The tropical forests are under assault everywhere. Were they to disappear altogether, then planetary temperatures − soaring in any case because of climate change − would rise by an additional 0.7°C. This would double the warming observed since 1850.

“We’re talking about conditions that are very different from anything humanity has ever experienced.”

So the moist, dense green cover that once screened vast areas of the equatorial belt is – like the oceans and the ice caps – a vital part of the climate machine.

Without the forests, the tropics would be significantly hotter. Because dense foliage turns ground water back into water vapour, it cools the air above it. Without the forests, temperatures would soar and large masses of air would start to rise as far as the stratosphere and start to ripple away to disturb weather patterns in the temperate zones.

The complete loss of tree cover in the Amazon basin – and a huge proportion has already disappeared – would reduce rainfall in parts of the US Midwest and Northwest and in the Southern states.

Were the Africa rainforests to vanish, there would be lower levels of rainfall in the Gulf of Mexico, in the Ukraine, and in Southern Europe. On the other hand, the Arabian Peninsula might benefit.

“In the last few centuries, the average global temperature has never varied by more than about one degree,” Professor Lawrence says. “Once we go above one degree – to 1.5 degrees or more – we’re talking about conditions that are very different from anything humanity has ever experienced.

“Farmers, so reliant on consistent and reliable growing conditions, could lose their bearings, and even their incomes, when facing these ups and downs in temperature and rainfall. While farmers may ultimately adapt to shifts in the season, it’s difficult, if not impossible, for farmers to adapt to increased floods or parched soils.”

Range of species

Studies such as these have their own uncertainties. However, the vital role of the rainforests as moderators of climate, as shelters for an extraordinary range of species, and as arbiters of the global water supply has been well established.

And as much tropical forest has already being cleared for cattle ranching and commercial agriculture, scientists have decades of data to work with.

The study found that the total loss of forests would also have direct local impacts, and people who cleared the forests for immediate gain would lose in the long run.

Without the forests in West Africa or the Congo, rainfall would drop by 40% or more, and temperatures would rise by 3°C. In the Amazon, if 40% of the forest was cleared, wet season rainfall would be reduced by 12% and dry season rainfall by 21%. – Climate News Network

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Sea urchins refine survival instincts as oceans change

Sea urchins refine survival instincts as oceans change

As climate change adds to the threat of extinction faced by many species, new research shows how sea urchins can adapt to the increasing temperature and levels of acidity in Antarctic waters.

LONDON, 17 December, 2014 − The sea urchins of the Southern Ocean could be safe from the threat of extinction. They may not enjoy global warming and the increasingly acid oceans, but new research indicates that they can adapt to climate change.

Researchers from the British Antarctic Survey and Bangor University in Wales − in what they describe as the largest study of its kind − collected 288 urchins of the species Sterechinus neumayeri from waters off the Antarctic Peninsula, carried them to Cambridge in the UK, and tested them in aquarium tanks over a two-year span, covering two full reproductive cycles.

During this time, they report in the Journal of Animal Ecology, they changed the water chemistry and turned up the temperature. The environment was made less alkaline and the thermometer notched up another 2°C − which are the conditions sea creatures could expect by 2100 if the world goes on burning fossil fuels and pumping greenhouse gases under the notorious business-as-usual scenario.

Intricate network

Research like this matters because it helps scientists to better understand the intricate network of environmental conditions that underwrite life on the planet, and because it provides answers to one of the big questions of climate change: how will it affect the estimated seven million species with whom humans share the planet?

According to the journal Nature, the lowest estimate is that 10 species become extinct every week, and the number could be as high as 690 a week. The uncertainty is an indicator of how little is known about the diversity of life on the planet.

The oceans, in particular, have been hard hit by human action. Other marine survival studies have not been encouraging: ocean acidification promises to be very bad news for corals, and therefore for the rich and diverse communities that depend on coral reefs. It also offers a survival threat to bivalves that exploit ocean chemistry to build protective shells.

Other experiments have shown that it can affect the survival behaviour of fish, and can even affect the lugworms that anglers favour as bait for fish.

But the news from the laboratory aquarium in Cambridge is encouraging. It took the sea urchins six to eight months to acclimatise and adjust to the new acidity levels and temperature − but they survived.

Artificial insemination experiments suggested that the urchins could spawn successfully under the new conditions, but to be sure of this, the researchers need more time. Antarctic invertebrates mature very slowly and sea urchins could live for 40 years or more.

“With predictions of warmer, more acidic waters in the future, this work shows how resilient these animals are to climate change,” said Melody Clark, project leader for the Adaptations and Physiology Group at the British Antarctic Survey.

“It also emphasises the importance of conducting long-term experiments in making accurate predictions. These animals live a long time, and so they do everything really slowly. They take around eight months to get used to new conditions, and two years to produce gonads (sexual organs). If we had stopped this experiment at three or even six months, we would have got very different results.”

Change habitat

Sea urchins cannot easily change their habitat: they must adapt or perish. But four-legged, warm-blooded terrestrial creatures have another option. In another instance of long-term research, scientists have established that small mountain mammals are prepared to move uphill as the climate warms.

Karen Rowe, biodiversity research fellow at Museum Victoria in Melbourne, Australia, and colleagues report in Proceedings of the Royal Society that they looked at records of observations of small mammals, made between 1911 and 1934 at 166 sites in the Californian mountains. Then, between 2003 and 2010, they surveyed the same species in the same locations.

Warmer winters are bad for hibernating mammals such as the chipmunk. Image: Vlad Lazarenko via Wikimedia Commons

Warmer winters are bad for hibernating mammals such as the chipmunk.
Image: Vlad Lazarenko via Wikimedia Commons

Altogether, they looked at 30,000 observations that recorded the foraging and breeding ranges of 34 species of chipmunk, gopher, pika, shrew, deer mouse, woodrat and squirrel at altitudes that varied from sea level to about 4,000 metres.

Moving uphill

Since the first, historic set of systematic measurements, the average temperatures in the region have climbed by 0.6°C, and many mammals have shifted their range accordingly – by moving uphill.

The pattern wasn’t consistent, but the researchers identified a problem for those animals that normally hibernate: warmer winters could be very bad news for creatures adapted to the chillier mountain slopes. And those animals that live at the highest altitudes might soon have nowhere to go.

“While mammals can avoid heat stress by behavioural means (such as shifting daily activity), warming winters lead to increased energy expenditures for hibernators and reduce the snow layer, which acts as insulation for non-hibernators,” they conclude.

“Global climate projections suggest that disappearing climates will be an increasing challenge for predicting future species’ responses.” – Climate News Network

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Tribal lands are vital for Amazon forest carbon sink

Tribal lands are vital for Amazon forest carbon sink

As land rights of indigenous peoples are increasingly being violated, new research shows that destruction of Amazon rainforest is a major threat not only to cultural identity but also to the global climate. 

LONDON, 5 December, 2014 − Scientists in the US and Latin America have once again confirmed the importance of the Amazon rainforest as a planetary resource and as a carbon sink to store carbon drawn down from the atmosphere. Sadly, they have also confirmed, once again, that it is at risk.

New research, released in time for the UN climate change conference being held in Lima, Peru, shows that 55% of the Amazon’s carbon is in the indigenous territories that are home to the regions’s 385 tribal peoples, or in formally-designated protected natural areas.

The forests are critical to the stability of the global climate, but also to the cultural identity of the forest dwellers of the region and the extraordinarily diverse ecosystems they inhabit.

Carbon-rich forests

“The territories of the Amazonian indigenous peoples store almost a third of the region’s above-ground carbon on just under a third of the land area,” said Wayne Walker, an ecologist and remote sensing specialist at the Woods Hole Research Centre, US, and lead author of a paper published in the journal Carbon Management.

“This is more forest carbon than is contained in some of the most carbon-rich tropical forests, including Indonesia and the Democratic Republic of the Congo.”

The authors also found that nearly 20% of tropical forests across the Amazon are threatened by legal and illegal logging, new roads, dams and the growth of agriculture, mining and the petroleum industries, at least in part because governments had failed to either recognise or enforce the land rights of indigenous peoples.

“Indigenous territories and protected areas are increasingly at risk, with potentially disastrous consequences”

The Amazon forest under study is a mosaic of 2,344 indigenous territories and 610 protected areas spread across nine nations. In terms of biological, cultural and linguistic diversity, these areas are exceptional.

They are also the cornerstone of conservation efforts. In this century alone, 253,000 square kilometres of Amazon rainforest – an area bigger than the UK − has been lost for a mix of reasons. And land rights of the indigenous peoples are also under attack, with more than half by area at risk.

But a loss to the Amazon peoples would also be a loss to the planet. The Amazon rainforest is a unique resource in biodiversity and is also a carbon sink of global importance. Every tree is a reservoir of atmospheric carbon. Every felled tree or patch of burned forest is so much carbon dioxide back in the atmosphere, to fuel global warming.

Secure landscapes

The scientists warn that the carbon stored in these supposedly secure landscapes is enough to destabilise the planet’s atmosphere – or contribute to its stability.

“If all the current plans for economic development in the Amazon are actually implemented, the region would become a giant savanna, with islands of forest,” said one of the authors, Beto Ricardo, of Brazil’s SocioEnvironmental Institute (Instituto Socioambiental).

“A vast proportion of indigenous territories and protected areas are increasingly at risk, with potentially disastrous consequences, including 40% of indigenous territories, 30% of protected areas, and 24% of the area that pertains to both.” – Climate News Network

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