Tag Archives: Warming

Satellite mapping shows ice caps’ faster melt rate

Surface water flows into a 'moulin' shaft in Greenland's ice cap Image: NASA via Wikimedia Commons
Surface water flows down into a ‘moulin’ shaft in the Greenland ice cap
Image: NASA via Wikimedia Commons

By Tim Radford

Scientists have been able to measure more accurately than ever the thickness of the world’s major ice caps  revealing that melting is causing the loss of 500 cubic kms of ice annually.

LONDON, 1 September, 2014 − German researchers have established the height of the Greenland and Antarctic ice caps with greater precision than ever before. And the new maps they have produced show that the ice is melting at an unprecedented rate.

The maps, produced with a satellite-mounted instrument, have elevation accuracies to within a few metres. Since Greenland’s ice cap is more than 2,000 metres thick on average, and the Antarctic bedrock supports 61% of the planet’s fresh water, this means that scientists can make more accurate assessments of annual melting.

Dr Veit Helm and other glaciologists at the Alfred Wegener Institute’s Helmholtz Centre for Polar and Marine Research in Bremerhaven, Germany, report in the journal The Cryosphere that, between them, the two ice sheets are now losing ice at the unprecedented rate of 500 cubic kilometres a year.

Big picture

The measurements used to make the maps were taken by an instrument aboard the European Space Agency’s orbiting satellite CryoSat-2. The satellite gets closer to the poles − to 88° latitude − than any previous mission and traverses almost 16 million sq km of ice, adding an area of ice the size of Spain to the big picture of change and loss in the frozen world.

CryoSat-2’s radar altimeter transmitted 7.5 million measurements of Greenland and 61 million of Antarctica during 2012, enabling glaciologists to work with a set of consistent measurements from a single instrument.

Over a three-year period, the researchers collected 200 million measurements in Antarctica and more than 14 million in Greenland. They were able to study how the ice sheets changed by comparing the data with measurements made by NASA’s ICESat mission.

More complex

Greenland’s volume of ice is being reduced at the rate of 375 cubic km a year. In Antarctica, the picture is more complex as the West Antarctic ice sheet is losing ice rapidly, but is growing in volume in East Antarctica.

Overall, the southern continent − 98% of which is covered with ice and snow − is losing 125 cubic km a year. These are the highest rates observed since researchers started making satellite observations 20 years ago.

“Since 2009, the volume loss in Greenland has increased by a factor of about two, and the West Antarctic ice sheet by a factor of three,” said Angelika Humbert, one of the report’s authors. − Climate News Network

Europe’s warming raises tropical disease risk

Spreading fear: the Aedes aegypti mosquito biting a human Image: US Department of Agriculture via Wikimedia Commons
Spreading fear: the Aedes aegypti mosquito biting a human
Image: US Department of Agriculture via Wikimedia Commons

By Tim Radford

As greenhouse gases raise temperatures in Europe, British researchers warn that the risk is increasing of the arrival of mosquito-borne diseases that kill many thousands of people every year in tropical regions.

LONDON, 27 August, 2014 − Add one more horror to the list of awful threats that climate change poses: it could introduce dengue fever in Europe.

Dengue fever is already a hazard for 2.5 billion people in humid tropical regions, and 50-100 million people a year are infected by the mosquito-borne disease. It puts 500,000 of them in hospital each year, and kills around 12,000 − many of them children. And there is still no widely effective vaccine.

Since Europe will get warmer as greenhouse gas levels in the atmosphere rise, conditions for the carrier mosquito will become more inviting.

Paul Hunter, clinical professor at the Norwich Medical School at the University of East Anglia in the UK, reports with colleagues, in the journal BMC Public Health, that in their mathematical model of disease spread, the Mediterranean and Adriatic coasts and the Po Valley and surrounding areas in north-east Italy emerged as likely breeding grounds for the carrier mosquito Aedes aegypti and the virus it can transmit.

Isolated cases

Their computer simulation already has support from medical records: the mosquito exists in urban Europe, and in 2010 there were isolated cases of dengue fever reported in Croatia and in France.

Such warnings are not new. Prof Hunter and his co-authors list reported fears of the spread of West Nile fever, leishmaniasis, Rift Valley fever, malaria, tick-borne encephalitis and other fearful infections as possible threats to Europe.

There were even warnings 25 years ago that climate change could make malaria − another mosquito-borne disease − once again a European scourge.

Malaria takes its name from the Italian, mal aria (bad air), and it was once endemic in Italy. A form of the infection also existed in Victorian England. But public health programmes, climate change and changes in land management eliminated the disease from those regions.

Now the risks to public health have begun to grow as international travel continues to increase, and as temperatures rise and the malaria mosquito expands its range in both altitude and latitude.

Dengue claims most of its victims in South-east Asia and the Pacific. But in the latest research, the East Anglia team looked at clinical data from Mexico, and climatic factors such as temperature, humidity and rainfall, and socio-economic data, to try to map the possible spread of the disease in the European Union’s 27 member states.

Rate of infection

Their findings were that the rate of infection by the virus, in the long term, could go from two per 100,000 inhabitants to 10 per 100,000 in some places, with the biggest risks being in the coastal areas of the Mediterranean and Adriatic, and in Italy’s north-east.

The authors acknowledge that their study is incomplete, and at a disadvantage. The temperature variation between winter and summer in Mexico is less dramatic than it is in Europe, and the mosquito is less likely to make it through a north European winter.

This kind of research is precautionary − a preliminary look at what could happen. But it does provide an early warning of potential hazards ahead.

“The exact incidence of dengue fever is dependent on several other factors, some of which we were unable to model at this stage,” Prof Hunter said.

“Nevertheless, public health agencies in high-risk areas need to plan, implement and evaluate effective reporting of mosquito populations and clinical surveillance by local doctors. Work should be carried out to improve awareness among health practitioners and the general public of the increased risk.” – Climate News Network

Politicians ignore people’s power pleas

A community-owned solar farm in the UK Image: Neil Maw/Westmill Solar Co-operative via WEikimedia Commons
Field of dreams: a community-owned solar farm near Oxford, UK
Image: Neil Maw/Westmill Solar Co-operative via Wikimedia Commons

By Paul Brown

Consumers worldwide increasingly want renewable energy sources to provide their electricity, yet many governments are ignoring them by continuing to exploit fossil fuels.

LONDON, 26 August, 2014 − Public support for renewable energies across the world continues to grow, particularly in more advanced economies − with solar power being especially popular.

At the same time, the policies of the governments in most of these richer countries do not mirror public opinion as many continue to develop fossil fuels, which do not command such popular support.

An example is the UK, where the government wants to exploit gas reserves by the controversial method of fracking – fracturing rock to allow the gas to reach the ground surface. The Conservative government is also promising to cut down on subsidies for onshore wind farms and to build nuclear power stations.

According to the public attitudes report published this month by the British government’s Department of Energy and Climate Change, 36% of the population supports the plan to build new nuclear stations, and only 24% support shale gas extraction by fracking.

Widespread support

In contrast, 79% of the public is in favour of renewable energies to provide electricity. The UK has plentiful renewable energy and is exploiting several different types. Solar panels are the most popular form, with 82% of the public supporting their widespread use on the roofs of private houses and, more recently, solar farms in fields in the countryside.

Other high scores for renewables were offshore wind (72% in favour), onshore wind (67%), wave and tidal (73%), and biomass (60%) − even though all need public subsidy to compete with fossil fuels.

Despite the government’s public support for nuclear, there has been no start on a new station because a subsidy offered by the government is being investigated as potentially illegal under European Union competition legislation. Fracking is still at the exploratory stage and requires years of investment before any power could be produced.

Massive growth

Meanwhile, renewables keep on growing. In the first three months of this year, they produced nearly one-fifth of the UK’s electricity. Renewable energy generation was 43% higher than a year previously, showing the massive growth in the industry.

Both onshore and offshore wind farms are growing quickly, with the UK now having the largest offshore wind industry in the world.

The electricity output from renewables this year was boosted by high rainfall in Scotland, helping the country’s hydropower stations to produce more power, and windy conditions over the whole of the UK improving wind power output.

The British government’s response to these successes has been a policy to reduce the subsidies for both wind and solar power, as improving technology and mass production lower unit costs, while increasing Treasury support for nuclear power and fracking.

Germany has a similar public support for fossil-free energy – with 69% of consumers agreeing that the subsidies are needed to switch electricity generation to renewables. Unlike in Britain, all nuclear stations in Germany are being closed because of public demand, and fracking is unlikely to be considered.

This is partly because 380,000 Germans already work in the renewable energy sector and its development is credited with helping Germany through the recent recession by creating manufacturing and maintenance jobs.

Attitudes in the US to climate change and renewables have also changed in recent years, despite a barrage of propaganda from the fossil fuel industry attempting to cast doubt on the scientists’ predictions of global warming. The public supports renewable energies, irrespective of their views on global warming.

Actively concerned

The Yale Project on Climate Change Communication reports that 18% of Americans are alarmed by climate change and its effect on their country, and 33% are actively concerned. This is in contrast to 11% who are doubtful that climate change is man-made, and a very vocal 7% who believe it is a hoax or conspiracy got up by scientists and journalists.

Dr Anthony Leiserowitz, the director of the Yale project, said “Whatever people’s view on whether climate change was man-made or not, all sectors agreed that there should be support for alternative energies. Subsidies for more fuel efficient and solar had wide public support. This cut across voters of all parties and no party.”

Even in Australia, where the government has repudiated all efforts to combat climate change, 70% of the public support renewable energies.

In the developing world, public knowledge of renewable energies is less, and so is the support − although solar power is popular. In India, where power cuts are a major headache for businesses, a recent poll showed that 50% of Indians want more renewable energy, and particularly solar power, believing it will help them get a more consistent electricity supply. – Climate News Network

Elections sideline São Paulo drought crisis

Drought has now hit dams on rivers such as the Paranapanema Image: José Reynaldo da Fonseca via Wikimedia Commons
Past prime: drought has now hit dams on rivers such as the Paranapanema
Image: José Reynaldo da Fonseca via Wikimedia Commons

By Jan Rocha

As South America’s biggest city suffers its worst drought in over a century, São Paulo state politicians are putting re-election prospects ahead of the need to introduce measures to address a desperate situation for millions of people.

SÃO PAULO, 25 August, 2014 − Outside the semi-arid area of the north-east, Brazilians have never had to worry about conserving water. Year in, year out, the summer has always brought rain.

But that has changed dramatically. São Paulo, the biggest metropolis in South America, with a population of almost 20 million, is now in the grip of its worst drought in more than a century − a water crisis of such proportions that reports on the daily level of the main reservoir arefollowed as closely as the football results.

The lack of rain is also affecting the dams that produce most of Brazil’s energy, highlighting the urgent need to diversify power sources.

And yet the state governor, wary of the effects on his prospects in forthcoming elections, has refused to introduce measures to ration, or even conserve, water.

Mighty rivers

Brazil is blessed not only with the mighty Amazon and all its huge tributaries, but also with dozens of other lengthy, broad rivers − once the highways for trade and slaving expeditions, but now providing waterways for cargo, power for dams, and water for reservoirs.It has at least 12% of the world’s fresh water supply.

But five of the principal rivers – the Tiete, Grande, Piracicaba, Mogi-Guaçu and Paraiba do Sul − that cross or border São Paulo, Brazil’s wealthiest state, have less than 30% of the water they should have at this time of year, according to data from the regional Hydrographic Basin Committee and from the National Electric System Operator (ONS).

Other major water sources – such as the Paraná, South America’s second biggest river, and the Paranapanema − are also suffering from the long dry period. The ruins of towns flooded for dam reservoirs have reappeared, fishermen’s boats are beached because the fish have disappeared, and navigation is at a standstill.

The transport of grain and other cargos to the port of Santos, via the river network, had to be suspended after the water level fell by up to eight metres. The equivalent of 10,000 lorryloads of cargo have been transferred by road so far.

Many industries have suspended their activities because of lack of water, and the drought has resulted in the loss of part of the coffee, sugar cane and wheat crops in one of Brazil’s most important agricultural states.

The hydrological period lasting from October 2013 to March 2014 was the driest for 123 years, according to the Agronomic Institute of Campinas, the oldest institute of its kind in Latin America .

Lowest volume

The federal government’s energy research company, EPE, found that in the first three months of 2014 the volume of rain was the third lowest since the 1930s.

It was the third consecutive year of reduction for the reservoirs of the hydroelectric dams that make up the South-east/Centre-West System, where many of Brazil’s biggest cities are located. From 88% in 2011, the volume of water in them had fallen to 38% by April 2014 – the month in which the dry season begins in this region.

By mid-August, the reservoirs of the Cantareira system, which supplies the water for almost 8.5 million of São Paulo’s inhabitants, had fallen to just 13.5% of capacity.

Yet the state government of São Paulo has so far refused even to admit that there is a crisis. The problem is the October elections, when Governor Geraldo Alkmim is running for re-election. Like most politicians, he does not want to be associated with a crisis. The word “rationing” is taboo.

Instead, unofficial rationing – what might be called rationing by stealth – is in operation. At night, the São Paulo Water Company, Sabesp, is reducing the pressure in the water system by 75%, leaving residents in higher areas of the city with dry taps.

Over 80% of the country’s energy comes from hydroelectric power, and dozens more giant dams are under construction or planned, mostly in the Amazon basin. The government has been strangely reluctant to invest in, or even encourage, other sources of abundant renewable energy, such as wind, solar and biomass.

The over-reliance on hydropower has already led to a distortion. The back-up system of thermo-electric plants, run on gas and diesel, and designed for emergencies, has had to increase production from 8% in 2012 to cover 25% of energy demand this year − thus contributing to higher carbon emissions.

Politics have also interfered with the special crisis committee set up to monitor the drought situation, with representatives from local and federal agencies unable to agree on what to do.

The Sao Paulo energy company, CESP, unilaterally decided this month to reduce the volume of water released from the shared Jaguari reservoir to the neighbouring state of Rio de Janeiro for electricity generation, in order to keep more for its own water needs.

Dangerous precedent

For Marcio Zimmerman, executive secretary of the Ministry of Mines and Energy, CESP’s action creates a dangerous precedent. “There will be chaos if everyone decides to rebel against the ONS,” he said.

The realisation that climate change is already leading to major changes in weather patterns has sounded alarm bells among the business community about the need to diversify energy sources and conserve water.

Early this month, at a seminar organised by the Brazilian Business Council for Sustainable Development, the chief executives of more than 20 top companies drew up a list of 22 crisis-related proposals to be put to the presidential candidates in October’s election.

Newspaper editorials are now urging the politicians to take their heads out of the sand and involve the population in a serious discussion on the crisis and its effects on the water supply, energy generation, and food production .

The Rio newspaper O Globo declared: “They belittle the potential for efficiency available in a society accustomed to waste. When they act, it might be too late.” – Climate News Network

Pre-history proof of climate’s see-saw sensitivity

The woolly rhinoceros once roamed wild on the plains of Europe Image: Public Library of Science via Wikimedia Commons
The woolly rhinoceros once roamed wild on the plains of Europe
Image: Public Library of Science via Wikimedia Commons

By Tim Radford

Computer simulations reaching back deep into the last Ice Age have enabled scientists to put a historic perspective on how even small variations in the climate system can lead to dramatic temperature change.

LONDON, 24 August, 2014 − It doesn’t take much to change a planet’s climate – just a little shift in the Northern hemisphere glacial ice sheet and a bit more carbon dioxide in the atmosphere. After that, the response is rapid. The tropical rain belt moves north and the southern hemisphere cools a bit, in some sort of bipolar see-saw response.

Sound familiar? It does, and it doesn’t. It all happened long before the internal combustion engine, or even the new Stone Age.

Researchers from the Alfred Wegener Institute’s Helmholtz Centre for Polar and Marine Research, Bremerhaven, the University of Bremen, Germany, and the University of Cardiff in the UK, report in Nature journal that they have made climate simulations that agree with observations of historical climate change that date back 800,000 years.

Long before the present alarms about global warming through the emission of carbon dioxide from fossil fuels, climate researchers were puzzled by the phenomenon of the Ice Ages and the “interglacials” that punctuated those long periods when the Arctic ice extended from the North Pole to the Atlantic coast of France, and over huge tracts of North America.

Vanished species

Mysteriously, and at great speed, the temperatures would rise by up to 10°C and the vast walls of ice would retreat. Lion, hyena and rhinoceros would invade the wild plains of what is now southern England, and now-vanished species of humans would hunt big game and gather fruit and seeds in the valleys and forests of Europe and America.

Since the end 10,000 years ago of the last ice age – itself a very rapid event – was the springboard for agriculture and civilisation, and eventually an Industrial Revolution based on fossil fuels, the story of climate change plays a powerful role in human history.

So any analysis of the tiny shifts in ice cover that seemed to trigger these dramatic, bygone events can be helpful in understanding the long story of the making of the modern world.

The researchers found a tentative scenario involving weak ocean currents, and prevailing winds that shifted the sea ice and allowed the oceans and atmosphere to exchange heat, pushing warmer water into the north-east Atlantic.

These changes precipitated a dramatic warming of the northern hemisphere in just a few decades, and the retreat of the glaciers for an extended period before the ice returned to claim much of the landmass again. But, overall, such changes tended to occur when sea levels reached a certain height.

“The rapid climate changes known in the scientific world as Dansgaard-Oeschger events were limited to a period of time from 110,000 to 23,000 years before the present,” said Xu Zhang, the report’s lead author.

“The abrupt climate changes did not take place at the extreme low sea levels, corresponding to the time of maximum glaciations 20,000 years ago, or at high sea levels such as those prevailing today. They occurred during periods of intermediate ice volume and intermediate sea levels”

Climate swings

Co-author Gerrit Lohmann, who leads the Wegener Institute’s palaeoclimate dynamics group, said: “Using the simulations performed with our climate model, we were able to demonstrate that the climate system can respond to small changes with abrupt climate swings.

“At medium sea levels, powerful forces − such as the dramatic acceleration of polar ice cap melting − are not necessary to result in abrupt climate shifts and associated drastic temperature changes.”

How much this tells anybody about modern climate change is open to debate. Right now, according to this line of evidence, the planet’s climate could be in one of its more stable phases of the Earth’s history.

But while the conditions for the kind of rapid change recorded in pre-history do not exist today, Prof Lohmann warns that “sudden climate changes cannot be excluded in the future”. – Climate News Network

‘Free riders’ undermine climate treaty hopes

Pollution haze over Beijing's Forbidden City Image: Yinan Chen via Wikimedia Commons
Sins of emission: pollution haze over Beijing’s Forbidden City
Image: Yinan Chen via Wikimedia Commons

By Alex Kirby

Norwegian researchers warn that hopes of getting an effective agreement on climate control will slip further away unless key polluting countries get serious about emissions reductions – and face sanctions if they don’t comply.

LONDON, 23 August, 2014 − An effective treaty to reduce greenhouse gas emissions will probably remain elusive, according to a new research study, because the steps likely to win political agreement would be ineffective, while those that could produce results would be politically unfeasible..

In fact, the Norwegian researchers conclude, the world is actually further away from an effective climate agreement today than it was 15 years ago, when the Kyoto Protocol was adopted.

The research is the work of a team from the Centre for International Climate and Environmental Research – Oslo (Cicero) and Statistics Norway, the country’s Central Bureau of Statistics.

Slow progress

The key question the researchers asked was what conditions could achieve an international agreement that would substantially reduce global climate emissions, in view of the extremely slow progress in the UN negotiations. They concluded that there is little basis for optimism.

Professor Jon Hovi, of the University of Oslo and Cicero, headed the project. He says there are three essentials for a robust agreement:

  • It must include all key countries − in other words, all the major emitters.
  • It must require each member country to make substantial emissions cuts.
  • Member countries must actually comply with their commitments.

While emissions cuts benefit all countries, he says, each country must bear the full costs of cutting its own emissions. So each is sorely tempted to act as a “free rider” − to enjoy the gains from other countries’ cuts while ignoring its own obligations.

“Cutting emissions is expensive, and powerful interests in every country proffer arguments as to why that particular country should be exempted,” Professor Hovi explains. “This inclines the authorities of all countries to take decisions that make them free riders.”

The researchers identified five types of free rider. Some countries − the US, for example − never ratified the Kyoto Protocol. Others, such as Canada, ratified it but later withdrew.

Developing countries ratified the Protocol, but it did not require them to make any cuts. The countries of Eastern Europe also ratified Kyoto, but it cost them nothing as their transition from a centrally-planned economy to a market economy meant their economies could not afford to cause significant emissions anyway.

Finally, the team says, some of the countries that accepted relatively deep commitments under Kyoto may have failed to live up to it. The final compliance figures are not yet available.

“Each and every country must be certain
that the other countries are also doing their part.”

“We must eliminate free riding,” Professor Hovi says. “Each and every country must be certain that the other countries are also doing their part. It’s the only viable option.”

He thinks any country avoiding its treaty commitments must face consequences: “Free riding must be met with concrete sanctions. The question is what type of enforcement could conceivably work and, if such a system exists, would it be politically possible to implement it.”

He and his colleagues recommend financial deposits, administered by an international secretariat. At ratification, each country would deposit a significant amount of money, and continue to do so annually until the agreed emissions reductions start. The total amount deposited by each country should match the cost of its commitments.

At the end of the reduction period, those countries that had met their cuts targets would receive a full refund of their deposit, plus interest. Those that had failed to do so would forfeit part or all of it.

Practical problems

But Professor Hovi concedes that not only would there be several practical problems with such a scheme, but there is little chance that it would be adopted anyway, because strict enforcement of an agreement is not politically feasible.

The researchers say that some countries – such as the US – support international systems of enforcement that can safeguard compliance with an agreement. “At the same time, other key countries have stated a clear opposition to potent enforcement measures – either as a matter of principle or because they know that they will risk punishment,” Professor Hovi says.

“For example, China opposes mechanisms that entail international intervention in domestic affairs as a matter of principle. China is not even prepared to accept international monitoring of its own emissions.

“The UN principle of full consensus allows countries opposed to enforcement measures to prevail by using their veto right during negotiations.”

Governments will try to revive hopes that agreement can be reached on an effective climate treaty when the UN Framework Convention on Climate Change (UNFCCC) meets in Paris late in 2015. − Climate News Network

Atlantic depths may hold key to heat hiatus

A jellyfish floats just above the seafloor of the deep Atlantic Image: NOAA/OAR/OER via Wikimedia Commons
A jellyfish floats just above the seafloor of the deep Atlantic Ocean
Image: NOAA/OAR/OER via Wikimedia Commons

By Tim Radford

Researchers analysing millions of oceanographic measurements believe they may finally have got to the bottom of the conundrum about why there is a slowdown in global warming despite greenhouse gas emissions rising.

LONDON, 22 August, 2014 − For years, researchers have puzzled over the temperature rises that haven’t happened – but scientists in China and the US believe they have cracked the mystery of the missing heat.

While calculations indicate that global average temperatures should be rising predictably, the planetary thermometers tell a different story.

But now Xianyao Chen, an oceanographer at the Ocean University of China in Qingdao, and Ka-Kit Tung, an atmospheric scientist at the University of Washington in Seattle, report in Science journal that they think they know where the notional extra heat has gone. It is at the bottom of the Atlantic Ocean.

And this time their conclusion isn’t based only on mathematical models and computer simulations. In their research − funded by the US National Science Foundation and the National Natural Science Foundation of China – they analysed millions of measurements of temperature and salinity taken by oceanographic instruments since 1970, and tracked the pathways that the heat must have taken since the beginning of the 21st century.

High temperatures

But first, a restatement of the conundrum. For more than a century, climate scientists have known that higher levels of carbon dioxide in the atmosphere mean higher atmospheric temperatures. For more than 30 years, every investigation has confirmed this link. And for the last 30 years of the 20th century, as greenhouse gas emissions increased, so did average temperatures.

This rise has continued, with 13 of the 14 warmest years ever recorded all falling in the 21st century, but the rate of increase unexpectedly slowed.

Researchers had expected that there would be some sort of heat hiatus, but not during the first years of the century, and they have been scratching their heads and examining the data again.

Some think that the measurements may be incomplete, or that natural cycles, such as the Pacific cooling event called La Niña, may be at play. Some have suggested that the pattern of trade winds may have a role in taking the warmth into the deep ocean, and some have suspected all along that the heat could be found far below the oceanic surface.

In the same week as the publication in Science, Reto  Knutti, a climate physicist at the federal technology institute ETH Zurich, and his colleague, Markus Huber, reported in Nature Geoscience that the apparent slowdown could be attributed to a cocktail of causes: a longer period of weaker solar irradiance – the sun has its own cycles of intensity − and to the cycle of El Niño and La Niña weather phenomena in the Pacific, and also to incompletely measured data.

“Many of the earlier papers had focused on
symptoms at the surface of the Earth”

But the Science report authors think they have an in-depth solution. “Every week, there’s a new explanation of the hiatus,” said Ka-Kit Tung. “Many of the earlier papers had focused on symptoms at the surface of the Earth, where we see many different and related phenomena. We looked at observations in the ocean to try to find an underlying cause.”

The oceans cover 70% of the planet, and are capable of storing 90% of the planet’s heat content. So the two Science report authors argue that a sudden shift in ocean salinity that corresponded with the slowdown of global warming could have triggered the movement of the heat to much deeper waters.

Saltier water is denser, sinks faster, and takes surface heat with it. As the two scientists see it, the depths of the North and South Atlantic have absorbed more heat in the last 14 years than the rest of the global ocean system put together.

This does not mean that global warming is not a problem: heat in the deep oceans is likely to come back to the surface, and to the atmosphere, sooner or later.

Natural cycle

The changes in the Atlantic ocean circulation system are part of a natural cycle that seems to date back many centuries. The surprise discovery by Chen and Tung is that the heat is tucked away in the Atlantic and Southern Oceans, rather than the Pacific − the suspected hiding place until now.

The argument is a complex one, and the latest research probably hasn’t settled the matter.

“All these analyses of ocean heat content are interpreting small changes in ocean temperature, and it will need to be picked over and repeated by others before being fully accepted,” said Professor Andrew Watson, head of the Marine and Atmospheric Science group at the University of Exeter, UK.

And Piers Forster, professor of climate change at the University of Leeds in the UK, said: “Most importantly, this paper is another nail in the coffin of the idea that the hiatus is evidence that our projections of long-term climate change need revising down.

“Variability in the ocean will not affect long-term climate trends, but may mean we have a period of accelerated warming to look forward to.” – Climate News Network

Climate and economy fan flames in Spain

A swathe of forest destroyed by wildfire in northern Spain Image: DM Molina Terrén via Wikimedia Commons
Burn scars: a swathe of forest destroyed by wildfire in northern Spain
Image: DM Molina Terrén via Wikimedia Commons

By Tim Radford

The combined forces of climate, economic and social change are leaving Spain increasingly exposed to the damaging and costly effects of wildfires.

LONDON, 21 August, 2014 – Climate change is gradually turning Spain into a fire zone – but it’s also the change in the economic climate that is inflaming the situation.

A research group reports in the journal Environmental Science and Policy that a mix of factors is behind the rise in both the numbers of forest fires and the areas of land scorched over the last 40 years.

Vanesa Moreno, a researcher in the geography department at the University of Alcalá in Madrid, and colleagues studied the pattern of fires in Spain from 1968 to 2010.

Natural outbreaks

Although Spain, like much of southern Europe, is expected to become more arid with global warming, and although some Mediterranean vegetation is adapted to − and even benefits from − natural fire outbreaks, the picture is not a simple one.

In the moister Atlantic north-west of the country, there are two fire seasons − at the end of winter, and in the summer. In the Mediterranean region, fires are more frequent in the long, hot summer.

Climate change, with more prolonged droughts and rising temperatures, is certainly a driving force, but another factor has been the way the land is now used.

Increasingly, agriculture has intensified and old customs have withered away. Traditional shepherding practices once relied on using fire to keep pastures clear, and, as these practices were abandoned, the risk of accidental scrub and bush and forest fire fell.

But at the same time, like everywhere else in the world, people began to abandon the rural landscape and move to the cities, which in turn means more uncontrolled vegetation growth, more tinder and dried leaves to ignite, and a greater risk of forest fire once more.

Additionally, there have been new reforestation policies, and new plantations for pulp and paper, so that there is more forest to catch fire.

Woodland now covers 37% of the 493,000 square kilometres under study, and the animal population per sq km has fallen from 45 sheep, goats or cattle to a mere 12. So social change, too is fuelling the fire hazard.

Alarming number

Across the Atlantic, from Alaska to California, wildfires are on the increase. Europe, too, has this summer been hit by an alarming number of fires. But knowledge is power, and the Spanish know what to expect.

Moreno says: “Management has evolved and become more effective through the acquisition of fire suppression resources, professional training, research, the introduction of technologies and prevention − something that has got a lot of attention in recent years.” says Moreno.

But that does not mean the fire situation is under control. “The occurrence of several fires at the same time means that resources and personnel have to be split, and extinguishing fires takes more time,” Moreno says.

“In this regard, the economic crisis has caused the workforce to be cut, which could reduce fire extinguishing ability.” – Climate News Network

Antarctic warming could accelerate sea level rise

Warming would cause more Antarctic ice to break off and melt Image: PIK/R.Winkelmann
Rising concern: warming would cause more Antarctic ice to break off and melt
Image: PIK (R.Winkelmann)

By Alex Kirby

An international study says warming is affecting not only the Arctic but also the Antarctic – and that could significantly raise global sea levels much faster than previously predicted.

LONDON, 20 August, 2014 − The effect of climate change on the world’s two polar regions looks like a stark contrast: the Arctic is warming faster than most of the rest of the Earth, while most of Antarctica appears to remain reassuringly locked in a frigid embrace.

But an international scientific team says the reality is quite different. The Antarctic is warming too, it says, and the southern ice could become the main cause of global sea level rise during this century − far sooner than previously thought.

The study, led by the Potsdam Institute for Climate Impact Research (PIK) in Germany, found that ice discharge from Antarctica could contribute up to 37 centimetres to global sea levels by 2100.

Computer simulations

The study is the first comprehensive estimate of the full range of Antarctica’s potential contribution to global sea level rise based on physical computer simulations. It combines state-of-the-art climate models and observational data with various ice models.

The results of the study − published in the European Geosciences Union’s journal, Earth System Dynamics − reproduce Antarctica’s recent contribution to sea level rise, as observed by satellites over the last two decades.

“If greenhouse gases continue to rise as before, ice discharge from Antarctica could raise the global ocean by an additional 1 to 37 centimetres this century,” says the study’s lead author, Anders Levermann, PIK professor of dynamics of the climate system.

“Science needs to be clear about the uncertainty,
so that decision-makers can consider the potential implications . . .”

“This is a big range – which is exactly why we call it a risk. Science needs to be clear about the uncertainty, so that decision-makers on the coast and in coastal mega-cities like Shanghai or New York can consider the potential implications in their planning processes.”

The scientists analysed how rising global average temperatures resulted in a warming of the ocean around Antarctica, influencing the melting of the Antarctic ice shelves.

Antarctica currently contributes less than 10% to global sea level rise and is a relatively minor player in comparison with the impact of the oceans’ increasing thermal expansion and the melting of glaciers.

But the major contributors to future long-term sea level rise are expected to be the huge volumes of ice locked up in Greenland and the Antarctic ice sheets. The marine ice sheets in West Antarctica alone could raise sea level by several metres over a period of several centuries.

The study’s computed projections for this century’s sea level contribution are significantly higher than the upper end of the latest projections by the Intergovernmental Panel on Climate Change. These suggest a probable rise by 2100 of around 60cm, although other estimates put the figure almost twice as high.

Even if governments can agree and enforce strict climate policies limiting global warming below the international target level of a maximum 2°C increase, Antarctica’s contribution to global sea level rise is expected still to range from 0 to 23cm this century.

Critical input

A co-author of the study, Robert Bindschadler, from the NASA Goddard Space Flight Center, said: “This paper is a critical input to projections of possible future contributions of diminishing ice sheets to sea level by a rigorous consideration of uncertainty of not only the results of ice sheet models themselves but also the climate and ocean forcing driving the ice sheet models.

“Billions of dollars, euros, yuan, etc, are at stake, and wise and cost-effective decision-makers require this type of useful information from the scientific experts.”

But major modeling challenges still remain. Datasets of Antarctic bedrock topography, for instance, are still inadequate, and some physical processes of interaction between ice and ocean cannot yet be sufficiently simulated.

The team also emphasises that the study’s results are limited to this century, while all 19 of the comprehensive climate models used show that the impacts of atmospheric warming on Antarctic ice shelf cavities will hit with a time delay of several decades.

However, Levermann says: “Earlier research indicated that Antarctica would become important in the long term. But pulling together all the evidence, it seems that Antarctica could become the dominant cause of sea level rise much sooner.” − Climate News Network

Health alert over fracking’s chemical cocktails

Gas wells at a fracking site in the US state of Pennsylvania Image: Gerry Dincher via Wikimedia Commons
Deep concerns: gas wells at a fracking site in the US state of Pennsylvania
Image: Gerry Dincher via Wikimedia Commons

By Tim Radford

Scientists in the US have established that some chemicals used in the controversial process of fracking to extract gas and oil could represent health and environmental hazards.

LONDON, 19 August, 2014 − Fracking is once again in trouble. Scientists have found that what gets pumped into hydrocarbon-rich rock as part of the hydraulic fracture technique to release gas and oil trapped in underground reservoirs may not be entirely healthy.

Environmental engineer William Stringfellow and colleagues at Lawrence Berkeley National Laboratory and the University of the Pacific told the American Chemical Society meeting in San Francisco that they scoured databases and reports to compile a list of the chemicals commonly used in fracking.

Such additives, which are necessary for the extraction process, include: acids to dissolve minerals and open up cracks in the rock; biocides to kill bacteria and prevent corrosion; gels and other agents to keep the fluid at the right level of viscosity at different temperatures; substances to prevent clays from swelling or shifting; distillates to reduce friction; acids to limit the precipitation of metal oxides.

Household use

Some of these compounds – for example, common salt, acetic acid and sodium carbonate – are routinely used in households worldwide.

But the researchers assembled a list of 190 of them, and considered their properties. For around one-third of them, there was very little data about health risks, and eight of them were toxic to mammals.

Fracking is a highly controversial technique, and has not been handed a clean bill of health by the scientific societies.

Seismologists have warned that such operations could possibly trigger earthquakes, and endocrinologists have warned that some of the chemicals used are known hormone-disruptors, and likely therefore to represent a health hazard if they get into well water.

Industry operators have countered that their techniques are safe, and involve innocent compounds frequently used, for instance, in making processed food and even ice-cream.

But the precise cocktail of chemicals used by each operator is often an industrial secret, and the North Carolina legislature even considered a bill that would make it a felony to disclose details of the fracking fluid mixtures.

So the Lawrence Berkeley team began their research in the hope of settling some aspects of the dispute.

Real story

Dr Stringfellow explained: “The industrial side was saying, ‘We’re just using food additives, basically making ice-cream here.’ On the other side, there’s talk about the injection of thousands of toxic chemicals. As scientists, we looked at the debate and asked, ‘What’s the real story?’”.

The story that unfolded was that there could be some substance to claims from both the industry and the environmentalists. But there were also caveats. Eight substances were identified as toxins. And even innocent chemicals could represent a real hazard to the water supply.

“You can’t take a truckload of ice-cream and dump it down a storm drain,” Dr Stringfellow said. “Even ice-cream manufacturers have to treat dairy wastes, which are natural and biodegradable. They must break them down, rather than releasing them directly into the environment.

“There are a number of chemicals, like corrosion inhibitors and biocides in particular, that are being used in reasonably high concentrations that could potentially have adverse effects. Biocides, for example, are designed to kill bacteria – it’s not a benign material.” – Climate News Network