Ancient shells offer evidence of how Ice Age ended

Ancient shells offer evidence of how Ice Age ended

Ocean sediment reveals that release of carbon stored deep in the sea is linked to the rise in atmospheric CO2 that caused the world to warm.

LONDON, 13 February, 2015 − Scientists believe they may have cracked the mystery of the end of the last ice age. The temperatures suddenly soared, and the glaciers went into retreat, because the deep southern ocean released huge quantities of carbon dioxide.

And the convincing answers have been delivered by analysis of the composition of calcium carbonate shells of ancient marine organisms.

The link between human burning of fossil fuels and the steady rise in atmospheric carbon dioxide levels was proposed more than a century ago and firmly established in the last 30 years.

But the ups and downs of planetary temperatures before the emergence of human civilisation are harder to explain. Fossil evidence suggests a link with carbon dioxide levels, but not necessarily a cause.

Bygone climates

Now paleoceanographer Miguel Martínez-Botí, from the University of Southampton, UK, and ocean and climate change researcher Gianluca Marino, from the Australian National University, report in Nature that they found their evidence in sediment cores – in effect, annual records of bygone climates – rich in the shells of tiny foraminifera called Globigerina bulloides.

This is a species that flourishes in conditions of high nutrients, acting as a kind of biological pump, gulping carbon from the atmosphere.

They found that high concentrations of carbon dioxide dissolved in surface waters of the southern Atlantic Ocean and the eastern equatorial Pacific coincided with rises in atmospheric CO2 at the end of the last ice age.

The implication is that these regions were the source of the carbon dioxide to the atmosphere.

“Our findings support the theory that a series of processes in the Southern Ocean changed the amount of carbon in the deep sea”

At their coldest, during the ice ages, carbon dioxide levels fell to 185 parts per million. During the interglacials, when the world warmed and lions and hyenas roamed the plains of Europe, the carbon dioxide levels rose to 280 ppm.

Right now, thanks to human activity, CO2 levels are rising ominously towards 400 ppm.

The oceans are home to about 60 times more carbon than the atmosphere and can, it seems, surrender it rapidly.

“The magnitude and rapidity of the swings in atmospheric CO2 across the ice age cycles suggest that changes in ocean carbon storage are important drivers of natural atmospheric CO2 variations,” Dr Martínez-Botí says.

“Our findings support the theory that a series of processes operating in the southernmost sector of the Atlantic, Pacific and Indian oceans, a region known as the Southern Ocean, changed the amount of carbon in the deep sea.

Into the abyss

“While a reduction in communication between the deep sea and the atmosphere in this region potentially locks carbon away from the atmosphere into the abyss during ice ages, the opposite occurs during warm interglacial periods.”

To arrive at their conclusion, the scientists had to analyse subtle evidence from the isotopic composition of the carbonate shells, and then use mathematical techniques to reconstruct a story of a great, faraway sigh of carbon dioxide from the ocean to the atmosphere.

The finding, based on calculated probabilities, is incomplete as there may have been other forces also at play.

Gavin Foster, associate professor in isotope geochemistry at the University of Southampton, says: “While our results support a primary role for the Southern Ocean processes in these natural cycles, we don’t yet know the full story. Other processes operating in other parts of the ocean, such as the north Pacific, may have an additional role to play.” – Climate News Network

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Power brokers’ chains hold back forests protection

Power brokers’ chains hold back forests protection

UK thinktank says inaction by the ‘Forest 500’ means global efforts to end deforestation by 2030 are not keeping pace with the rate of destruction.

LONDON, 11 February, 2015 − The world will not, on present rates of progress, reach its goal of ending tropical deforestation within 15 years.

The Global Canopy Programme (GCP), a thinktank based in Oxford, UK, says many of those who could protect the forests by ensuring that deforestation does not contribute to commodity supply chains are failing to act.

The GCP, which draws together international experts on tropical forests, has compiled what it says is the first comprehensive ranking of the “Forest 500 − power brokers who control the global supply chains that drive over half of tropical deforestation.

Influential actors

It has identified, assessed and ranked 250 companies, with total annual revenues of more than US$4.5 trillion; 150 investors and lenders; 50 countries and regions; and 50 other influential actors, as it calls them – a wide-ranging group of banks, international agencies and non-governmental organisations.

Together, the 500 control the complex global supply chains of key “forest risk commodities” − such as soya, palm oil, beef, leather, timber, pulp and paper − that have an annual trade value of more than $100 billion and are found in over 50% of packaged products in supermarkets.

The GCP says only a small minority of the 500 have equipped themselves to tackle this problem, which makes a significant contribution to climate change and other environmental problems, as well as worsening poverty.

Deforestation and land use change cause more than 10% of global greenhouse gas emissions, undermine regional water security, and threaten the livelihoods of more than a billion people.

Assessed against dozens of policy indicators, only seven of the Forest 500 scored the maximum number of points − companies Groupe Danone (France), Kao Corp. (Japan), Nestlé S.A. (Switzerland), Procter & Gamble (US), Reckitt Benckiser Group (UK), Unilever (UK), and banking and financial services giant HSBC (UK).

“Deforestation is in our chocolate and our toothpaste, our animal feed and textbooks, buildings and furniture, investments and pensions”

At the other end of the scale, the GCP says, 30 companies − many based in Asia and the Middle East − and numerous investors scored zero points. Countries received varied scores, with Latin American nations scoring high in forested regions and the Netherlands and Germany coming top among countries that import forest risk commodities.

Of investors assessed, sovereign wealth funds and hedge funds scored very low for their sustainable investment policies, while banks achieved higher scores.

“We are currently all part of a global deforestation economy,” says Mario Rautner, a GCP programme manager.  “Deforestation is in our chocolate and our toothpaste, our animal feed and our textbooks, our buildings and our furniture, our investments and our pensions.”

“Our goal with the Forest 500 is to provide precise and actionable information to measure the progress of society to achieve zero deforestation.

Global supply chains

“Together, these 500 countries, companies and investors have the power to clean up global supply chains and virtually put an end to tropical deforestation.”

He adds: “Though the Forest 500 findings highlight that much work needs to be done, the good news is that a number of big players across sectors are demonstrating the leadership that is needed.

“Putting policies in place is just the necessary first step in addressing tropical deforestation, and their implementation will be critical in order to transition to deforestation-free supply chains by 2020.”

At the UN Climate Summit last year, prominent representatives from business, governments, indigenous communities and civil society signed the New York Declaration on Forests. It spells out ambitious commitments to halve deforestation by 2020 and to end it by 2030.

A similar pledge to achieve net zero deforestation by 2020 has been made by the Consumer Goods Forum, a global association of companies and service providers, including major manufacturers and retailers. − Climate News Network

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Climate change triggers threats to marine ecosystems

Climate change triggers threats to marine ecosystems

A two-way migration of fish species between the northern Pacific and Atlantic as oceans warm could have drastic ecological and commercial impacts.

LONDON, 7 February, 2015 − The Atlantic halibut is about to go where no Atlantic halibut has gone before – into the Pacific. And it could meet the Alaska pollock coming in the other direction.

Just as marine commerce could soon exploit the opening of the fabled north-west or north-east passages between the two great oceans, so could at least 80 species of fish.

Mary Wisz, an ecologist now with the Danish DHI group, but formerly at the Arctic Research Centre of Aarhus University in Denmark, reports with colleagues in Nature Climate Change that as sea temperatures increase, and food sources begin to flourish at the highest latitudes, shoals of fish from the Atlantic could reach the Pacific along once almost impassable seaways north of Arctic Canada and Siberia.

Northerly species

The last such large-scale transfer was nearly three million years ago, with the opening of the Bering Strait. But climate conditions that were once harsh have begun to open migration opportunities for the northerly species in both oceans, the researchers say.

Such changes have happened before. Since the opening of the Suez Canal in 1869, the Mediterranean has been invaded by 55 Red Sea species, with a “drastic impact” on commercial fisheries.

Fish are already moving north in response to climate change, and Dr Wisz and her colleagues modelled what would happen to 515 species of fish under predicted conditions of global warming later this century.

By 2050, the scientists believe, trans-Arctic traffic will accelerate, and by 2100, 41 Atlantic species − among them cod and herring − could reach the Pacific, while 44 species could get into the Atlantic.

They warn: “This exchange of fish species may trigger changes in the North Atlantic and the North Pacific, with ecological and economic consequences to ecosystems that at present contribute 39% to global marine fish landings.”

Changes to marine chemistry also threaten the balance of power in the oceans

The Danish-led team was essentially modelling temperature, currents and spawning strategies to see which species were most likely to find new grounds. But changes to marine chemistry also threaten the balance of power in the oceans.

The seas are predicted to become more acidic as more carbon dioxide gets into the atmosphere, and this change in water chemistry is likely to affect not just fish and shellfish but also entire communities of creatures.

Scientists have tested the fauna that foul ships’ hulls. These are the tiny barnacles and squirts that attach themselves to hard surfaces wherever they can in the oceans.

Lloyd Peck, a biologist with the British Antarctic Survey, and colleagues report in Global Change Biology that they tested creatures from a lagoon off the Algarve in Portugal, in aquarium tanks.

One set of tanks was filled with normal sea water; in the other set, the sea water was set at levels of acidity predicted to be normal within the next 50 years. Within 100 days, in the more acid tanks, the make-up of the community that colonised the hard surfaces had begun to change.

Worms with hard shells in the more acidic tanks were reduced to a fifth of their normal levels, but sponges and sea squirts multiplied twofold and even fourfold.

“Our experiment shows the response of one biofouling community to a very rapid change in acidity,” said Professor Peck. “What’s interesting is that the increased acidity at the levels we studied destroys not only the building blocks in the outer shell of the worms itself, but the binding that holds it together.

“Many individuals perish, but we also showed their larvae and juveniles are also unable to establish and create their hard exoskeletons.”

Altered behaviour

Climate change could also alter the behaviour of the green sea turtle, Chelonia mydas, according to an international team led by Professor Kyle Van Houtan, of the Nicholas School of the Environment and Earth Sciences at Duke University, US.

The researchers studied six years of turtle observations off Oahu, Hawaii, and 24 years of satellite data for sea surface temperatures in regions that are home to 11 populations of the turtle.

They report in Biology Letters that they know why the turtles crawl up onto the beach to bask. Not all populations bask, but the ones that do tend to sprawl in the sand do so to regulate body temperatures, and were least likely to bask when local winter sea temperatures stayed above 23°C. When the seas stayed warm, the turtles stayed in the water.

Given the predicted ocean temperature rises over the next century, the scientists calculate that green turtles may stop basking altogether by 2100. – Climate News Network

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EU aids shoppers to steer clear of harmful palm oil

EU aids shoppers to steer clear of harmful palm oil

New food labelling rules on giving consumers in Europe more information should help to protect the world’s tropical forests and the climate.

LONDON, 6 February, 2015 A European Union decision to give consumers more information about the food they buy could mean good news for tropical countries whose forests are threatened by the expanding trade in palm oil.

Palm oil is found in 50% of supermarket products, such as soaps and shampoos, and in many sorts of food. But the EU requirement that food products containing the oil must now be labelled clearly should help to dispel doubts about the damage it can cause.

Producing the oil often involves felling virgin rainforest, reducing biodiversity and destroying the habitat of endangered species such as orangutans, elephants and tigers, and ruining the livelihoods of local people.

It also involves the release of large quantities of carbon dioxide into the atmosphere when carbon-rich tropical forests are cleared for plantations.

Short-term impact

The EU move is not expected to change things overnight. Simon Counsell, executive director of the Rainforest Foundation UK, said: “We imagine that the impact in the short term will be fairly limited, as it’s hard to see busy people scanning through a long list of ingredients on manufactured foods to see if the product contains palm oil.

“So we believe there is still very much a need for a clear and simple product guide such as ours, so that people can know to avoid altogether products that contain palm oil.”

Indonesia and Malaysia produce 85% of the global palm oil supply, and wholesale logging there is a direct threat to some of the last remaining habitats of orangutans. There are thought to be around only 60,000 surviving in the wild.

Elizabeth Clarke, business and biodiversity programme manager at the Zoological Society of London, said: “Palm oil production is vital to the economies of countries where it is grown, but it also has serious negative environmental impacts, particularly if grown unsustainably.

“We don’t have any space left to farm − we don’t benefit from anything”

“We are working with the industry to promote sustainable practices and responsible investment through our new Sustainable Palm Oil Transparency Toolkit, SPOTT.

“More is needed to reduce pressures on wildlife, ensuring a future for the remaining 300 Sumatran tigers whose habitat is at severe risk of being lost from deforestation as a result of irresponsible practices.”

New areas face threats in Africa and Latin America. In the Congo, for example, a million acres are already being cultivated for palm oil, with a further 284 million acres of pristine rainforest currently at risk. The Congo contains the world’s second largest tropical rainforest − after the Amazon − and is one of the most important wilderness areas left on Earth.

Many people living in the forests feel powerless. Chief André Sayom, head of the village of Nkollo, in Cameroon, told the Rainforest Foundation: “We don’t have any space left to farm. We don’t benefit from anything. We’ve been displaced more than once already.

Explicit statement

Life becomes very difficult when these multinationals set foot somewhere. These projects need to be looked at in the long term, and populations need to be informed and consulted”.

The new EU rules, introduced last December, require companies that use palm oil in their food products to label them with an explicit statement, rather than simply relying on vague, catch-all references to “vegetable oil”. They can also now highlight their use of certified sustainable palm oil

Unilever is one of the world’s major buyers of palm oil, purchasing around 1.5 million tonnes annually about 3% of global production. It promised that all the oil directly sourced for its European foods business would be 100% traceable and certified sustainable from the end of 2014.

Palm oil production is big business. The industry is worth $44 billion, with the world consuming 55 million tonnes in 2013 − nearly four times the 1990 total. And the World Bank expects today’s global demand to have doubled by 2020. Climate News Network

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Climate cranks up extinction threat to Borneo mammals

Climate cranks up extinction threat to Borneo mammals

Endangered species in one of the world’s biodiversity hotspots face even greater danger as climate change adds to loss of habitat caused by deforestation.

LONDON, 3 February, 2015 − One in three of the mammal species of Borneo could see their habitat reduced by a third by 2080 − just because of climate change alone.

Given that the rainforests of Borneo are right now also being felled, burned and converted to commercial plantation, nearly half of all mammal species will lose more than a third of their remaining home range within the next 65 years.

Among the first to feel the heat will be those species that are already endangered – creatures such as the greater nectar bat, the otter civet, and the flat-headed cat.

Conservation challenge

Matthew Struebig, a tropical ecologist at the University of Kent, in the UK, and colleagues report in the journal Current Biology that they considered the challenge of conservation in one of the world’s great biodiversity hotspots − but which is also under pressure from population growth, economic expansion and continued pressure on the last stands of one of the world’s great forests.

The researchers assembled a comprehensive map and inventory of data for 13 species of primate, 23 carnivores and 45 kinds of bat. Altogether, they examined 6,921 records and observations.

“Only a modest amount of additional land . . . would be needed outside of existing reserves to safeguard many mammal species”

They developed a framework to model the amount of suitable habitat that each of their 81 species needed, and tried to identify the forest land that – if saved from the woodsman’s axe – would be best suited as a natural reserve for that species.

Then they set about incorporating future conditions, dependent on different climate data. They ended up with eight versions for each species: a total of 4,698 maps describing the habitats of the large and small animals that swing through the tree canopy, nest in tree trunks, or hunt among the roots and underbrush.

It was calculated that somewhere between 11% and 36% of the island’s mammal species would lose 30% of their habitat by 2080, and the ecological conditions that suited them best would move uphill by between 23% and 46%, as global climate warmed because of greenhouse gas emissions.

Commercial pressures

Deforestation – which happens because of economic and commercial pressures, and is independent of climate change – would make things worse, so that 30% to 49% would lose a significant slice of living space.

Warnings like these are intended to prevent extinction − to preserve some of the remarkable fruits of millions of years of evolution − and the researchers will be presenting their findings to the governments of Indonesia, Malaysia and Brunei.

“Only a modest amount of additional land on Borneo – about 28,000 square kilometres, or 4% of the island – would be needed outside of existing reserves to safeguard many mammal species against threats from deforestation and climate change,” Dr Struebig says. – Climate News Network

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Chimps’ survival hopes jeopardised by climate change

Chimps’ survival hopes jeopardised by climate change

One of our closest animal relatives is at risk of being wiped out as changing rainfall patterns threaten to destroy its Central African habitat.

LONDON, 30 January, 2015 − Climate change is a challenge for chimpanzees, too. New research warns that a primate subspecies – one of humanity’s closest animal relatives – could become endangered within five years

The threatened subspecies of the common chimpanzee is Pan troglodytes ellioti, and there are only 6,000 remaining individuals, surviving in two populations in Cameroon.

Field biologist Paul Sesink Clee, of Drexel University, US, and colleagues report in BMC Evolutionary Biology that they combined climate, environmental and population data to model how the chimpanzees’ preferred habitats would change with climate under a “business as usual” scenario in which the world went on burning fossil fuels.

Habitat change

Underlying such research is the larger question of how variation in habitat drives evolutionary change: why are there four subspecies of chimpanzee, and how much does geography and habitat have to do with it?

So the scientists made a chimpanzee population map, and imposed it on a map of habitats.

They found two distinct populations of the chimpanzee − one in the mountainous rainforests of western Cameroon, and one in a distinctive region of grassland, forest and woodland in central Cameroon.

Then they simulated how these habitats would change under global warming scenarios by 2020, 2050 and 2080.

“Preliminary projections suggest that rainfall patterns will change dramatically in this region of Africa”

Their findings were that the mountain rainforest habitat would survive, but the lowland dwellers would decline quickly under all scenarios by 2020, and could disappear almost entirely under the worst case scenario by 2080.

Since half of the entire population of Nigeria-Cameroon chimpanzees survive in this habitat, the suggestion is that the chimpanzees are particularly vulnerable to climate change.

Severely affected

The researchers did not take into account the opportunities for the chimpanzees to migrate, or to adapt to new circumstances. They point out that Central Africa in particular, and the continent in general, is likely to be severely affected by climate change.

“Preliminary projections suggest that rainfall patterns will change dramatically in this region of Africa, which will result in significant alterations of forest and savanna habitats,” the report says.

“Models of global climate change also have been used to show that 30% of plant and animal species are at risk of extinction if the rise in mean global temperature exceeds 1.5°C − an increase that is nearly certain to occur under future climate scenarios.” – Climate News Network

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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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