Emissions threaten age of uncertainty for carbon dating

Emissions threaten age of uncertainty for carbon dating

New study warns that rising CO2 levels from the burning of fossil fuels will undermine the precision with which once-living things can now be scientifically dated.

LONDON, 24 July, 2015 – Climate change driven by increasing levels of atmospheric carbon dioxide will not just damage the health of the planet. A UK scientist now warns that it will also make life increasingly difficult for archaeologists, forensic scientists, art experts, fraud and forgery detectives, and people who detect ivory poachers.

That is because the swelling volume of carbon pumped into the atmosphere from factory and power station chimneys and motor and airline exhausts is beginning to artificially “age” the planet’s atmosphere and bedevil attempts to use the technology known as carbon dating.

If emissions continue under the now-notorious “business as usual” scenario, then by 2050 a brand-new cotton shirt will have the same radiocarbon-dating age as the cloak worn by William the Conqueror when he invaded Britain in 1066.

But if, on the other hand, the world’s governments do move swiftly to curb fossil fuel emissions, then by 2050 a brand-new cotton shirt will seem only 100 years old.

Forensic scientists exhuming a skeleton, Egyptologists investigating an ancient tomb, and fraud detectives concerned with suspected forgeries of Renaissance paintings could still possibly make allowances for that.

Natural ratio

Radiocarbon dating is a 70-year-old technique now used with increasing precision to date anything once alive from the last 50,000 years. It exploits the natural ratio of two isotopes of carbon in the atmosphere.

Plants, and the animals that eat them, absorb radioactive carbon-14 and stable carbon-12 from the atmosphere in proportions which – except during the atmospheric nuclear weapons tests in the 1950s and 1960s − have not changed much from the Ice Ages to the beginning of the Industrial Revolution.

When the tree dies or the animal becomes old bones, the carbon-14 decays at a predictable rate, and the ratio that remains in the laboratory sample is a measure of the specimen’s age.

But Heather Graven, a lecturer in climate physics and Earth observation at Imperial College London, reports in the US journal Proceedings of the National Academy of Sciences that by 2020, as the fossil fuel emissions mount up, the fraction of carbon-14 in the atmosphere could drop to such a level that carbon-dating could become increasingly uncertain.

“Given current emissions trends . . . ‘ageing’ of the atmosphere is likely to occur much faster and with a larger magnitude than previously expected”

Fossil fuels are reservoirs of carbon from plants and algae that died so long ago that all the carbon-14 has decayed. When carbon dioxide exhausts from combustion engines reach the atmosphere, they increase the levels of non-radioactive carbon, artificially ageing the atmosphere and, accordingly the new growths that exploit the atmospheric carbon.

Dr Graven warns that now, from the point of view of an archaeologist using radiocarbon dating, the planet’s atmosphere is ageing at the rate of 30 or so years for every year of international inaction.

If there are no steps to reduce emissions, then by 2050 the atmosphere will have a signature of what carbon ratios were 1,000 years ago. By 2100, just one human lifetime away, the atmospheric clock will have been turned back to the era of Imperial Rome.

That means that a freshly-dead dung beetle that falls into an Egyptian tomb dating from the reign of Cleopatra would have the same radiocarbon age as the scarab that was trapped in the tomb under the sarcophagus 20 centuries ago.

“Given current emissions trends, fossil fuel emission-driven artificial ‘ageing’ of the atmosphere is likely to occur much faster and with a larger magnitude than previously expected,” Dr Graven concludes.

“This finding has strong and, as yet, unrecognised implications for many applications of radiocarbon in various fields, and it implies that radiocarbon dating may no longer provide definitive ages for samples up to 2,000 years old.”

Historic sources

It also could, for instance, mean that border officials may not be able to distinguish museum collection ivory from illegally-poached elephant tusks, that fraud officers will not be able to confirm the age of costly single malt whisky or vintage claret, and that Jewish and Christian scholars may no longer be able to date important historic sources such as the Dead Sea Scrolls, or resolve doubts about the much-contested provenance of iconic relics such as the Shroud of Turin.

Dr Graven, who uses radiocarbon technology to study the global carbon cycle, told Climate News Network: “I was inspired by how many innovative applications there are for radiocarbon in diverse fields. This made me realise that fossil fuel emissions are likely to have an impact on these various uses for radiocarbon.

“By quantifying the potential changes over this century with model simulations, this study could help other scientists who use radiocarbon to prepare for forthcoming changes.” – Climate News Network

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UK’s leading scientists urge immediate climate action

UK scientists urge immediate climate action

The pre-eminent institutions in British science and engineering – some with long records of promoting fossil fuels – say the UK should lead the way to a zero carbon world. 

LONDON, 23 July, 2015 – Twenty-four of Britain’s most learned scientific societies have joined forces to urge the British government to act now to curb greenhouse gas emissions.

They want the UK to take the lead in intergovernmental talks in Paris in December, and keep global warming to an average of 2°C this century.

The societies want drastic reductions in the burning of fossil fuels, a shift towards energy efficiency and renewable sources of energy, and other changes to sidestep damaging climate change as a consequence of the atmospheric build-up of carbon dioxide.

A joint communiqué agreed by organisations that speak for the most advanced research in the humanities, the social sciences, the arts, science, medicine and engineering urges action by governments, individuals, business, local communities and public institutions, to make the transition to a zero carbon world.

That any of the institutions has signed the communiqué is no surprise: many of them have delivered such advice separately, and some of them many times. What is significant about this latest statement is that all sorts of scholarly authorities with quite different origins have been united in one unequivocal statement.

Hydrocarbon pioneers

The Geological Society of London, for instance, the oldest such in the world, is backed by the fossil fuel industry and has sponsored petroleum, gas and coal prospecting and exploitation for much of its 200-year history.

The Royal Society of Chemistry was an intellectual centre for scientists and industrialists who pioneered the use of hydrocarbons derived from stores of crude oil and seams of coal.

The Royal Society provided intellectual support for the scientists who made the Industrial Revolution possible – and then endorsed the conclusions by a new generation that first identified the dangers inherent in atmospheric pollution, and then began systematically measuring the cost to the planet’s environment of such advances.

The signatories also include the Institutions of Civil Engineers and Chemical Engineers, members of which played a powerful role in the spread and advance of a fossil-fuel burning economy, as well as the Zoological Society of London, which has been more concerned with protecting the wildlife at risk from human activity, and the Royal Meteorological Society,  whose members have identified, measured and projected all the evidence of climate change.

“At or above 4°C, the risks include…fundamental changes to human activities that today are taken for granted”

Calling on the British government to show leadership on climate action, when the world’s nations meet in Paris in December to try once more to reach an enforceable agreement on cuts in greenhouse gas emissions, Lord Stern, the President of the British Academy, said: “The UK led the world with both the modern scientific revolution and the industrial revolution, and must again lead now on the creation of a safer, cleaner and more prosperous world.

“Tackling climate change is a responsibility for the whole world, but the UK has a special position at the forefront of international efforts.”

The communiqué points out that while climate change poses far-reaching threats, the ways in which humankind tackles the issue present great opportunity, with vast potential for innovation in low-carbon technologies.

But not to take action could be catastrophic. “At or above 4°C, the risks include species extinction, global and regional food insecurity, and fundamental changes to human activities that today are taken for granted,” the communiqué says. – Climate News Network

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Quantum leap taken in measuring greenhouse effect

Quantum leap taken in measuring greenhouse effect

New technique for analysing satellite data will allow scientists to predict more accurately how much the Earth will warm as a result of carbon dioxide emissions.

LONDON, 8 July, 2015 – British scientists have devised a new way to observe the greenhouse world, enabling researchers to measure with exquisite accuracy how atmospheric carbon dioxide builds up, migrates, evolves and absorbs radiation.

The technique will allow more accurate predictions about how much the Earth is likely to warm over the next few decades as a result of the inexorable rise in atmospheric CO2 – from car exhausts, power station chimneys and burning forests – that drives global warming and climate change.

More than a century has elapsed since the Swedish Nobel laureate Svante Arrhenius first predicted the greenhouse effect, but scientists have until now only been able to establish the way CO2 absorbs light, with accuracies of about 5% at best.

Exploit laws

But Oleg Polyanksy and Jonathan Tennyson, professors in the Department of Physics and Astronomy at University College London, and colleagues report in the journal Physical Review Letters that they can exploit the laws of quantum mechanics to narrow the uncertainty to 0.3%.

The consequence is that a range of dedicated satellite missions – among them Japan’s Greenhouse Gas Observing Satellite (GOSAT), the US space agency NASA’s Orbiting Carbon Observatory-2 (OCO-2) and potential European Space Agency missions such as CarbonSat − will not just be able to identify industrial sources of CO2 and map their spread, but watch the gas in action, slowly warming the planet by as much as 5°C by 2100.

“It is necessary to have a very precise answer
to the question: how much radiation does
one molecule of CO2 absorb?”

“Billions of dollars are currently being spent on satellites that monitor what seems to be the inexorable growth of CO2 in our atmosphere,” Professor Tennyson says. “To interpret their results, however, it is necessary to have a very precise answer to the question: how much radiation does one molecule of CO2 absorb?

“Up until now, laboratory measurements have struggled to answer this question accurately enough to allow climate scientists to interpret their results with the detail their observations require.”

The orbiting satellite has become the climate scientist’s most prolific data delivery machine. There are satellites measuring the shrinking of the ice caps and the rate at which the ice is melting.

Besides an arsenal of weather monitors, satellites are using sophisticated sensors to monitor sea level rise, changes in ocean acidity and soil moisture, agricultural success in India, and even the energy spent in lighting up the world’s cities at night.

Warming puzzle

All these studies are part of the great global warming puzzle, but for most of the last 50 years, confirmation of what a greenhouse gas does has mainly rested on the match of CO2 levels in the atmosphere and the consequent rise in global average temperatures.

The University College team, with colleagues in Russia, the US and Poland, tried another approach. They started with the exact quantum mechanical equations obeyed by a molecule such as CO2 , then harnessed computers and subtle laboratory technologies to measure the different “colours” or wavelengths of light absorbed by molecules.

Each wavelength carries a precise energy, and highly-accurate measurements for small laboratory samples should enable researchers to scale up to equivalent accuracies for the entire atmosphere.

That means that they will be able to observe the intricacies of global warming − more or less as it happens − from high orbit, and make increasingly accurate predictions about future global warming. – Climate News Network

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Climate change may knock seafood off the menu

Climate change may knock seafood off the menu

Researchers warn of a serious threat to fish, mussels and other marine species as carbon dioxide acidifies the world’s waters and increases temperatures.

LONDON, 7 July, 2015 – Pink salmon – the smallest and most abundant of the Pacific salmon species, and a supper table mainstay in many parts of the world – may be swimming towards trouble.

And they are not the only dish likely to disappear from the menu. Mussels, oysters, clam and scallop could all become scarcer and more expensive as the seas become more acid. And as the world’s waters warm, fish will start to migrate away from their normal grounds at an ever-increasing rate.

New research shows that as the world’s waters acidify because of carbon dioxide levels in the atmosphere, the pink salmon (Oncorhynchus gorbuscha) could become smaller and less likely to survive.

Potentially problematic

Previous studies have repeatedly and consistently explored potentially problematic consequences of change in the pH value of the world’s oceans. The higher the carbon dioxide concentrations in the air as a consequence of the burning of fossil fuels, the greater the change in oceanic acidity levels.

But researchers at the University of British Columbia, Vancouver, and colleagues looked at the special problems of freshwater fish.

Only about 0.8% of the world’s water is fresh – that is, found in lakes and rivers – but freshwater species represent 40% of all fishes. Salmon spawn and the young are reared in fresh water, before taking to the seas to mature, then returning to repeat the cycle.

The Vancouver scientists report in Nature Climate Change that they tested very young embryos in water at acidity levels expected at the end of this century, and observed them for 10 weeks.

They found that these laboratory-reared salmon were smaller, and their ability to smell was reduced, which could mean problems in returning to their spawning grounds or for scenting danger and responding to it.

“It is not too late for society to benefit greatly from immediate reductions in CO2 emissions”

At the age of seaward migration, they were less able to use oxygen in their muscles, which promised problems finding food, evading predators or making long journeys.

“The increase in carbon dioxide in water is actually quite small from a chemistry perspective, so we didn’t expect to see so many effects,” said Michelle Ou, lead author of the study. “The growth, physiology and behaviour of these developing pink salmon are very much influenced by these small changes.”

Salmon aren’t the only freshwater fish at risk from climate change. Research published in the journal Environmental Toxicology and Chemistry reveals that a rise in water temperatures of 5°C could make common pesticides and industrial contaminants ever more toxic.

Ronald Patra, an environmental scientist at the Department of Planning and Environment in New South Wales, Australia, and colleagues tested rainbow trout, silver perch, rainbowfish and western carp gudgeon at temperatures higher than optimum for the species and in the presence of endosulfan, chlorpyrifos and phenol − all of which wash into waterways from the land.

Results varied according to pollutant, species and temperature, but, overall, all three chemicals became increasingly toxic as water temperatures rose.

Future toxicity

On the coast of Mangalore in southwest India, where mussel farming has become a growing industry, researchers decided to test future toxicity conditions for the green mussel.

The Society of Experimental Biology meeting in Prague learned that the bivalves were raised in high temperature and low salt conditions and exposed to toxic algae and bacteria of the kind that might be expected in a changing climate, which in turn affected the timing of the monsoon in ways that could lower seawater salinity.

“This is likely to increase the chance of outbreaks of toxic plankton blooms and make farming bivalves such as mussels increasingly challenging,” the meeting was told.

But changes to water chemistry – once again, the shift in pH values as yet more carbonic acid builds up in the seas – create problems enough for the commercial shellfisheries.

Wiley Evans, research associate at the Ocean Acidification Research Centre of the University of Alaska Fairbanks, and colleagues report in the Public Library of Science journal PLOS One that shellfish farmers off the Alaska coast might, at extra expense, have to start modifying the sea water in their hatcheries because, the researchers reported, they expect “significant effects” from acidification by 2040.

The scientists monitored for 10 months the effects of water chemistry changes on oyster, clam, scallop and other shellfish larvae.

Alaska – with a limited growing season, melting glaciers that affect salinity, and with colder waters that more readily dissolve carbon dioxide – is a special case.

But in general, as researchers have repeatedly found, increasingly corrosive waters would make it more difficult for shellfish to exploit the calcium carbonate minerals needed to make shells.

Shellfish spend their maturity in one spot, whereas fish can and do shift their grounds when the conditions become uncomfortable − with consequences for established commercial catches such as sardines and sea bass.

Likely to migrate

But a 5°C average warming in global atmospheric temperatures – and climate scientists have repeatedly warned that this is possible before 2100 – means that fish are likely to migrate away from their existing habitats considerably faster than they are doing now.

Jean-Pierre Gattuso, of the Oceanological Observatory in Villefranche, France, and colleagues looked at the evidence on a global scale and report in Science journal that, without attempts to mitigate global warming, the oceans and the creatures in them will be seriously affected by temperature changes and acidification.

This is very bad news for the millions of people in the communities that depend on the seas for a living.

“On a positive note, we still have options to substantially reduce these impacts now, but the longer we wait the fewer and fewer options we have,” warns co-author William Cheung, of the fisheries centre at Canada’s University of British Columbia.

Commenting on the research, Jason Hall-Spencer, a professor of marine biology at Plymouth University in the UK, said: “This review screams at me that the evidence is in, and it is not too late for society to benefit greatly from immediate reductions in CO2 emissions.” – Climate News Network

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Deaths mount as Pakistan heatwave is linked to climate

Deaths mount as Pakistan heatwave is linked to climate

More than 1,200 people have died as the result of an intense heatwave in southern Pakistan, and experts warn of more hot weather to come.

ISLAMABAD, 6 July, 2015 − Pakistan’s lack of preparedness in the face of increasingly intense weather events is being blamed for a growing death toll following what has been one of the most sustained heatwaves in the country since records began.

And weather experts say that the extreme heat – which lasted for much of the second half of June, and was felt most in the southern province of Sindh – is linked to climate change.

Ghulam Rasul, director general of the Pakistan Meteorological Department (PMD), told Climate News Network that the intense heat was caused by an unusually persistent area of low pressure over the Arabian Sea off Pakistan’s coast.

“Usually, in summer, cool winds blow from the sea to land, and in winter the situation is the opposite,” he said. “This moderates temperatures in the port city of Karachi, but this summer, this didn’t happen.”

Climate taskforce

Pervaiz Amir, formerly a member of a special taskforce on climate change set up by Nawaz Sharif, Pakistan’s prime minister, said: “The mortality from heatstroke could have been avoided had the Sindh provincial government responded to a heatwave forecast issued by the Pakistan Meteorological Department.”

Karachi, a city of nearly 20 million, was worst hit, with bodies piling up in the city’s morgues, and hospitals crammed with people suffering from severe heatstroke as daytime temperatures climbed to well over 40°C for extended periods.

About 65,000 heatstroke patients were treated at the city’s hospitals, and the death toll in southern Pakistan climbed above 1,200.

“This is leading to more extreme weather events, with floods and heatwaves becoming more intense and frequent in recent years”

Chronic energy shortages – a common occurrence in Pakistan – added to the problem, and the heatwave came during Ramadan, the Muslim fasting period when people do not eat or drink during daylight hours.

Experts say Karachi has also suffered from what’s known as the urban heat island effect, with poor urban planning and a lack of green spaces making conditions even hotter.

Social workers say the majority of those who have died have been the poor and homeless. At one stage, Karachi’s cemeteries ran out of space for burying the dead.

Mohsin Iqbal, a climate scientist at the state-owned Global Change Impact Study Centre in Islamabad, says temperature increases in Pakistan are above the rise in average global temperatures.

Extreme events

“This is leading to more extreme weather events, with floods and heatwaves becoming more intense and frequent in recent years,” he says.

Climate experts say weather patterns throughout the Asian sub-continent are changing, with more intense periods of heat, delays in the monsoon season and a greater incidence of drought conditions.

In April and May this year, many parts of India were hit by an intense heatwave, causing the death of more than 2,000 people.

AccuWeather, a global forecasting service, says delays in the arrival of monsoon rains and further hot periods are likely to exacerbate drought conditions in Pakistan and northwest India in July and August, threatening crop production across a wide swathe of land. – Climate News Network

  • Saleem Shaikh is a freelance climate change and science journalist, based in Islamabad, Pakistan.

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Coal investment is the most urgent climate threat

Coal investment is the most urgent climate threat

Head of the OECD says wealthy countries should help poorer nations that cannot afford to replace coal with low-carbon alternatives.

LONDON, 5 July, 2015 − The future of coal has come under scrutiny from a perhaps unlikely source – the head of the organisation representing wealthy nations that relied on coal for 32% of electricity generation last year.

Angel Gurría, secretary-general of the Organisation for Economic Co-operation and Development (OECD), said the scale of new investments in “unabated” coal-fired electricity generation − where greenhouse gases are emitted directly to the atmosphere − posed the most urgent threat to the Earth’s climate.

Speaking in London, he said governments should be sceptical about the benefits of coal for their citizens. They should rethink the role of coal in energy supply, and conduct a more rigorous evaluation of its true costs.

Environmental costs

With prices failing to fully account for the environmental, health and financial costs of coal, many of the coal plants being built today might have to be shut down before the end of their economic lifetimes.

The OECD, founded to stimulate economic progress and world trade, has 34 members drawn from the richest and most powerful industrialised countries.

But Gurría, in a passage that will hearten many developing countries in the approach to the UN climate change negotiations in Paris in November/December this year, said that if poorer nations could not afford low-carbon alternatives, then richer countries should find the money to close the cost gap.

“We have been in a process for over 20 years and, so far, the commitments simply don’t add up

Without new mitigation measures, coal generation is projected to emit more than 500 billion tonnes of CO2 between now and 2050 − eating up around half the remaining carbon budget that scientists say is consistent with keeping a global temperature rise below 2°C.

In any case, Dr Gurría said, countries’ contributions to emissions reductions after 2020 are not consistent with a 2°C pathway. He said the carbon clock was ticking and the Paris COP21 climate conference must give a clear and credible signal that governments are determined to go for a higher level of ambition.

“Calling something a process doesn’t guarantee an outcome,” he said. “We have been in a process for over 20 years and, so far, the commitments simply don’t add up.”

Continued investment in coal is one of many “misalignments” between climate goals and countries’ policies in other domains, Dr Gurría said.

Action undermined

A report by the OECD, its specialised Nuclear Energy Agency, the International Energy Agency and the International Transport Forum says policy misalignments undermine climate action in areas from tax to trade, electricity market regulation and land use.

The report says two-thirds of global energy investments still go into fossil fuels, 50% of agricultural subsidies in OECD countries harm the climate, and various tax provisions encourage fossil fuel production and use.

This “policy incoherence”, as the report describes it, limits the effectiveness of countries’ climate change efforts, and increases the cost of the transition to a low-carbon economy.

Dr Gurría urged governments to consider what needed to be done to resolve such misalignments, starting with a demand that each ministry should regularly report on which of its policies run counter to desirable climate results. − Climate News Network

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Transport sharing boosts health, wealth and climate

Transport sharing boosts health, wealth and climate

Growing public involvement in schemes to share cars and bicycles is clearly good for the environment, but it also saves money and improves people’s health.

LONDON, 4 July, 2015 − New research into how people’s habits change shows that everyone benefits from car-sharing schemes − apart from car manufacturers who suffer a loss of sales.

Car sharing is a growing social trend across Europe and North America and is expected to increase by 36% annually to 2020, especially in compact cities where people do not need a car every day but want to use one for family trips and holidays.

In the European Union, 72% of people live in cities and account for 70% of energy consumption, so car sharing could make a big contribution to reducing emissions as well as cutting air pollution. The increasing use of phone apps to locate the nearest vehicle or bicycle in a sharing scheme means organisation has become cheaper and simpler.

Sprawling cities

Even in North America, where cities are more sprawling, research shows there were 23 car-share operators in the US in 2014. They had 1.3 million members, sharing 19,115 cars.

In a survey conducted for the Transportation Sustainability Research Centre at the University of California Berkeley, investigations into the habits of 9,500 car-sharers showed that a quarter of the participants had sold their cars, and another quarter had postponed purchase of a new one.

The researchers concluded that one shared car replaced between nine and 13 privately-owned cars. For each family, this meant a 34%-41% reduction in greenhouse gas emissions.

“We’ll be living closer together in the future,
and sharing vehicles will be even more
efficient in a compact city”

Another positive finding was that car-sharers made more use of public transport, bicycles and walking. They saved money because of not having to pay out on car insurance, repairs and other costs.

Lars Böcker, a researcher in the Department of Sociology and Human Geography at Oslo University, Norway, says: “Sharing of bicycles and cars is an innovative means of transport. We’ll be living closer together in the future, and sharing vehicles will be even more efficient in a compact city.

“There are a number of advantages to joining a car-share co-operative where members share cars as needed, or a subscription scheme where you locate the closest car available when you want to go somewhere.

“Users don’t have to think about fixed expenses, parking problems, insurance, battery charging or fuelling. The idea is that you have access to a vehicle only when you need it.”

Positively inclined

Böcker has studied attitudes to the sharing of products and services in Amsterdam. He found that women were more positively inclined to sharing than men, and that older people were less willing to share services and products than younger people. People with a non-Western cultural background shared more than the average.

The survey also inquired about the motivation for sharing. In the case of car sharing and ride sharing, it was a mix of environmental considerations and the desire to save money, according to the research.

It also showed a broad swathe of the population is positively inclined to the sharing economy.

Böcker says: “This means that these schemes have a potential for considerable up-scaling; they do not represent a niche phenomenon. Only a few people need a car daily in the city, but many need access to a vehicle now and then . . .

“Sharing can give more people access to a vehicle in just this sort of situation, without there being an increase in the total amount of vehicle transport.” – Climate News Network

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Global warming threatens colder climate for Europe

Global warming threatens colder climate for Europe

New evidence that increased melting of sea ice as the Earth warms could weaken the Gulf Stream and reduce temperatures in western Europe.

LONDON, 3 July, 2015 – Scientists have yet again warned that weakening ocean circulation in the North Atlantic could deliver a climate paradox − a colder Europe as a consequence of global warming.

A study published in Nature Climate Change found that as sea ice off Iceland and Greenland retreats, the flow of cold, dense water to the bottom of the North Atlantic ocean could be reduced, and therefore weaken the warming effects of the Gulf Stream.

The great submarine current − sometimes called the Atlantic Conveyor − flows south to surface in the tropics as the Gulf Stream, which then flows north again to deliver tropic warmth to European coasts.

However, a slowdown in the natural overturning of the ocean could weaken the Gulf Stream, which in turn could cool the atmosphere over the British Isles and western Europe.

“A warm western Europe requires a cold North Atlantic, and the warming that the North Atlantic is now experiencing has the potential to result in a cooling over Western Europe,” says Kent Moore, a professor of physics at the University of Toronto Mississauga, Canada.

Calamitous change

Such a possible collapse of a natural oceanic system is predicated as one of the irreversible tipping points that could result in calamitous climate change.

Scientists have twice warned in the past six months that such change could be irreversible, unless governments jointly decide to dramatically reduce greenhouse gas emissions from the combustion of fossil fuels by switching to renewable sources of energy.

Another research group reported in March this year on how the changing salinity of the northern ocean waters − because of the increasing flow of meltwater from land-borne glaciers − threatened a weakening of the Atlantic Conveyor.

“The heat exchange is weaker – it’s like turning down the stove 20%”

In the latest study, Professor Moore and colleagues from Norway, the US and the UK looked not at changes in ocean salinity, but at the exchange of heat between sea and air.

Climate is driven by contrasts, and the flow of heat between water and wind in winter has weakened by around 20% since 1979. The Arctic is the fastest-warming region of the planet, and changes in the polar climate can have dramatic consequences for the temperate zones.

Prof Moore and his colleagues looked at wintertime data from the Iceland and Greenland Seas between 1958 and 2014, then used computer simulations to model potential changes to the Conveyor − more formally known to oceanographers and climate scientists as the Atlantic Meridional Ocean Circulation.

Cold and salty

The warm current loses its heat to the atmosphere as it moves north, and water that is both cold and salty is denser and more likely to descend.

The most effective place for such a process to happen is at the edge of the sea ice. If the sea ice retreats, then so does the region of maximum heat exchange. For the past 10,000 years or so, this heat exchange has happened at the ideal spot for surface waters to sink. Any change might not be for the better.

The Gulf Stream is the agency that makes Britain, for example, about 5°C warmer than Labrador in Canada, on the same latitude. A British government chief scientific adviser once calculated that the Gulf Stream delivered the warmth of 27,000 power stations. So if it weakens, Europe could start to feel the chill.

“The heat exchange is weaker – it’s like turning down the stove 20%,” Prof Moore says. “We believe the weakening will continue and eventually cause changes in the Atlantic Meridional Overturning Circulation and the Gulf Stream, which can impact the climate of Europe.” – Climate News Network

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Greenhouse gas-guzzlers spurn extra carbon dioxide

Greenhouse gas-guzzlers spurn extra carbon dioxide

Minutely small marine plants called diatoms mitigate climate change by consuming carbon dioxide and producing oxygen. But they may reject the rising levels of the greenhouse gas.

LONDON, 1 July, 2015 – Diatoms – those tiny ocean-dwelling photosynthesisers that produce a fifth of the planet’s oxygen each year – may not gulp down more carbon dioxide more enthusiastically as greenhouse gas levels in the atmosphere continue to rise.

Instead, they may switch off and use the gas more efficiently. If so, the consequences for the rest of the planet could be uncomfortable.

Climate scientists who try to model the machinery of the atmosphere have always banked on a “fertilisation effect” from at least some of the extra CO2 pumped into the atmosphere by the human burning of fossil fuels and the clearance of the forests. They may no longer be able to do so.

The discovery – reported in Nature Climate Change – is based on laboratory experiments with one single-celled phytoplankton species called Thalassiosira pseudonana and meticulous study of its genetic mechanisms.

Rising concentrations

It may not be a sure guide to what actually happens in the crowded, complex world of climate change later this century. But all phytoplankton are survivors of the same evolutionary history, and many of them are known to be equipped with carbon-concentrating mechanisms to make the most of the available carbon dioxide in the atmosphere. So what happens to one could be true for all.

Gwenn Hennon, an oceanographer at the University of Washington in Seattle, US, and colleagues decided to work out what happened to their laboratory diatoms in atmospheres in which carbon dioxide levels continued to rise to 800 parts per million later this century.

Right now, the concentration is almost 400 parts per million, but for most of human history until the invention of the internal combustion engine, and the exploitation of fossil fuels, it has been around 280 parts per million. A third of the emissions from factory chimneys and motor exhausts is absorbed by living things in the oceans, starting with diatoms and other phytoplankton.

The Seattle team found that while many photosynthesisers do grow faster with more CO2, the oceanic diatoms did not: they responded vigorously at first, but as long as there was a normal supply of other nutrients, over 15 generations, they slowed down.

Slow response

“There are certain genes that respond right away to a change in CO2, but the change in the metabolism doesn’t actually happen until you give the diatoms some time to acclimate,” said Hennon, a doctoral student. “Instead of using that energy from the CO2 to grow faster, they just stopped harvesting as much energy from light through photosynthesis and carried out less respiration.”

Studies like this are an illustration of the intricacy and complexity of climate science. How the living world responds to greater human emissions of carbon dioxide from fossil fuels is key to all models of future climates, but researchers in general have expected the plant world to respond by consuming more, and slowing the rate of change overall.

There is some evidence that this is happening. Half of all the anthropogenic or human-made CO2 has been gulped down in the form of more lusty growth by vegetation, but this “negative feedback” effect has been countered by other factors: more greenery in the Arctic, for instance, could accelerate global warming, and anyway, as plants grow more vigorously, so do plant predators.

And increasingly, climate scientists have begun to realise that although the responses of the forests and arid lands  are vital factors, the big players could be the creatures hardly anyone ever sees: the fungi and tiny fauna in the soil  beneath the trees, and of course the phytoplankton in the oceans.

Oxygen creators

The Seattle calculation is that the evolutionary history of the diatoms explains the carbon-concentrating mechanisms in their genetic inheritance. Microbes are life’s foundation, and single-celled creatures evolved over three billion years when CO2 levels in the atmosphere were at colossal concentrations.

The diatoms and their ancestors were the creatures that created the oxygen atmosphere in which all other complex living things evolved. An enzyme evolved to help the first microbes cope with high levels of CO2, and has survived for billions of years.

“There hasn’t been another enzyme to replace it since, so plants and algae that photosynthesise have an enzyme that functions better at a higher CO2 level than we currently have,” Hennon said.

“When the CO2 remains high for a long time, however, the diatoms make a more radical metabolic shift. They decrease photosynthesis and respiration to balance the cell’s energy budget. In other words, the diatoms use less energy to grow at the same rate.” – Climate News Network

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Alaska’s glaciers melt faster as climate change speeds up

Alaska's glaciers melt faster as climate change speeds up

Climate change rather than natural causes is the main cause of Alaska’s glacier loss, which is set to speed up, US scientists say.

LONDON, 30 June, 2015 – The glaciers of Alaska are melting and retreating: the chief cause is climate change and the loss of ice is unlikely to slow, according to a new study by US scientists.

They calculate that the frozen rivers of the Pacific coast of America’s northernmost state are melting fast enough to cover the whole of Alaska with 30 cms of water every seven years.

Since Alaska is enormous – it covers 1.5 million square kilometres and is the size of California, Texas and Montana put together – this adds up to a significant contribution to sea level rise.

“The Alaska region has long been considered a primary player in the global sea level budget, but the exact details of the drivers and mechanisms of Alaska glacier change have been stubbornly elusive,” said Chris Larsen, a geophysicist at the University of Alaska Fairbanks, and lead author of a study in Geophysical Research Letters.

Taxonomy of change

Scientists from the University of Alaska and the US Geological Survey analysed studies of 116 glaciers in the Alaska region over a 19-year-period to estimate the rate at which ice melted and icebergs calved.

They used airborne lidar remote sensing technology and other techniques, historical data and a global glacier inventory to establish a kind of taxonomy of glacier change.

The Columbia Glacier in Prince William Sound had retreated more than 19 kilometres because of iceberg calving and had thinned by 450 meters in height since 1980. But, unexpectedly, tidewater glaciers – those that end in the ocean – seemed to make comparatively little contribution to sea level rise.

“Instead we show that glaciers ending on land are losing mass exceptionally fast, overshadowing mass changes due to iceberg calving, and making climate-related melting the primary control on mountain glacier mass loss,” Dr Larsen said.

Big contributor

He and his colleagues calculated that Alaska is losing ice at the rate of 75 billion metric tons a year. Such research is just one more piece of careful cross-checking in the great mosaic of climate research: another systematic confirmation that overall, glaciers are not losing ice in response to some natural cycle of change of the kind that occasionally confuses the picture for climate science.

The agency at work is largely global warming as a response to the steady rise in atmospheric carbon dioxide as a consequence of the burning of fossil fuels.

Mountain glaciers represent only 1% of the total ice on the planet: the other 99% is found in Greenland – which is melting fast – and in the great frozen continent of Antarctica, where ice mass is being lost at an increasing rate.

But although the mountains of the temperate and tropic zones bear only a tiny percentage of the planet’s ice, their melting accounts for almost a third of the sea level rise currently measured by oceanographers, and this melting will go on to become a big contributor to the sea levels later this century.

“Alaska will continue to be a major driver of sea level change in the upcoming decades”

Across the border in Canada, glaciologists have warned that the country will lose a huge volume of flowing ice, and while one team has confirmed that air pollution rather than global warming long ago began to strip Europe’s Alps of their glaciers, in general mountain peaks are warming faster than the valleys and plains below them.

Geophysicists and glaciologists have established that the glaciers of the tropical Andes are at risk, and in the Himalayan mountain chain glaciers seem to be in inexorable retreat with consequences that could be devastating for the many millions in the Indian subcontinent and in China who rely on seasonal meltwater for agriculture.

Glaciers are by definition hard to study – they are high, cold and in dangerous terrain – and such research is inevitably incomplete: the scientists for instance excluded glaciers smaller than three square kilometres. But together these small patches of flowing ice account for 16% of Alaska’s glaciated landscape. The 116 glaciers in the survey together added up to only 41% of the state’s glaciated area.

But the pattern established by the Fairbanks team suggests that melting will accelerate with climate change. “Rates of loss from Alaska are unlikely to decline, since surface melt is the predominant driver, and summer temperatures are expected to increase,” said Dr Larsen.

“There is a lot of momentum in the system, and Alaska will continue to be a major driver of sea level change in the upcoming decades.” – Climate News Network

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