Greener cities are best at taming urban heat

Greener cities are best at taming urban heat

As humans become an urban species researchers find evidence that cities with more green space are best for human wellbeing. 

LONDON, 2 September, 2015 – For the first time in human history, more than half the world now lives in cities. Later this century, the proportion could rise to two-thirds.

Even without global warming because of a build-up of carbon dioxide in the atmosphere, itself the consequence of fossil fuel combustion, the cities are feeling the heat.

That is because dark materials and hard surfaces – tarmacadam, brick, cement, tiles, slates, gutters, railway tracks, flyovers, motorways and so on – absorb the heat but not the rainwater that, as it evaporates, could damp down that heat.

As a consequence, cities become “heat islands”: places conspicuously hotter than the surrounding countryside. According to a report in Nature, the annual average temperature in Los Angeles in California has risen by more than 2°C since 1878, and by mid-century the sprawling megalopolis is predicted to face 22 days a year of extreme heat: that is, with temperatures of more than 35°C.

Now British and US scientists are trying to work out the shape of the ideal city. Pack people together with lots of green spaces around, say the British. And keep the people cool with trees, parks, roof gardens to help them withstand the heat, add the Americans.

Researchers at the University of Exeter in the UK and the University of Hokkaido in Japan report in the journal Frontiers in Ecology and Environment that they analysed nine case studies of cities worldwide to work out the arrangements with most benefits to humans.

Dense but spacious

The answer – separate from the climate question – is that dense settlements but with big parks and nature reserves deliver the greatest sense of well-being and the healthiest urban ecosystems.

“As populations continue to grow, it’s vital that we expand our cities and build new ones in a way that is most sustainable for ecosystems, and which provides the greatest benefits to urban residents”, said the lead author, Iain Stott, from the University of Exeter’s Environment and Sustainability Institute on the Penryn campus in Cornwall.

“Our research finds that compact developments that include large green spaces are essential for the delivery of ecosystem services. For humans to get the most benefit, however, combining this approach with greening of built land using street trees and some small parks and gardens is the best method.”

Rather than focus on selected cities, a team led by scientists from the US space agency NASA report in Environmental Research Letters that they took an overall look at what asphalt and concrete do to the whole United States.

The satellite data told a familiar story: those tracts of America covered by impervious surfaces such as roads, pavements, roofs and car parks were in summer up to 1.9°C warmer than the surrounding rural zones, and in winter 1.5°C.

“Urbanisation is a good thing…but we could probably do it a little bit better”

“This has nothing to do with greenhouse gas emissions. It’s in addition to the greenhouse gas effect. This is the land use component only”, said Lahouari Bounoua, of Nasa’s Goddard Space Flight Centre in Greenbelt, Maryland, and lead author. “Anywhere in the US small cities generate less heat than mega-cities.”

Green things cool by evapo-transpiration. Broadleaf trees with big leaf areas can cool cities more than forests of pines with fine needles. The message is that green is good for cities and cities are good for the environment.

Cities in arid places – Phoenix in Arizona is a case in point – can paradoxically be cooler than the surrounding desert because residents bring lawns that must be watered, and trees for shade.

This creates another problem. Water is a scarce resource and rising urban temperatures could make it even scarcer. Researchers from the University of Florida report in the journal Technology and Innovation that a survey of homeowners in Orange County, Florida, found that 64% of drinking water went to irrigate the lawns. In summer this proportion went up to 88%.

Whatever the urban problems, global warming and climate change will make them worse, but cities offer ways to reduce energy use and save carbon dioxide emissions.

“Urbanisation is a good thing”, Dr Bounoua said. “It brings a lot of people together in a small area. Share the road, share the work, share the building. But we could probably do it a little bit better.” – Climate News Network

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Climate models may misjudge soils’ carbon emissions

Climate models may misjudge soils' carbon emissions

How soil organisms cope with decaying vegetation is much less certain than climate models suppose, researchers say, and carbon emission estimates may be wrong. 

LONDON, 29 August, 2015 – Some of the microscopic creatures which live in the soil are able to digest dead plants and trees, turning their contents into gas and minerals.

But researchers say their work show that our understanding of how organic material is decomposed is fundamentally wrong, calling into question some current climate models.

The researchers, from Lund University, Sweden, and the University of New Hampshire, USA, have published their study in the journal Ecological Monographs. They say it means that climate models which include micro-organisms in their estimates of future climate change must be reconsidered.

When plants or trees die, their leaves and branches fall to the ground and the organic matter which is absorbed by the soil is then decomposed, mainly by the activity of fungi and bacteria, which convert the dead materials into the main greenhouse gas, carbon dioxide, and mineral nutrients.

Until now, the Lund team says, scientists had thought that high-quality organic materials, such as leaves that are rich in soluble sugars, were mainly decomposed by bacteria, leaving the lower-quality matter, like cellulose and lignin, to be broken down mainly by fungi.

Expectations confounded

Previous research has suggested that organic material decomposed by fungi results in less CO2 and nutrient leakage compared with matter decomposed by bacteria.

This is important for the climate models in use today, as any change in the loss of CO2 and mineral nitrogen would alter the soil’s contribution to greenhouse gases and eutrophication, the process in which the release of excessive chemical pollution causes algal blooms in watercourses.

The researchers have now examined the relative significance of fungal and bacterial decomposition over a 23-year period. “In contrast with expectations, there was no evidence that high-quality organic material was mainly broken down by bacteria. In fact, the data strongly suggested the contrary”, says Johannes Rousk, researcher in microbial ecology at Lund.

“There was also no evidence to suggest that organic material broken down by fungi reduced the leakage of carbon dioxide into the atmosphere, or the leakage of nutrients. Once again, the results tended to suggest the contrary”, he says.

He and his co-author, Serita D Frey, say the results could have consequences not only for climate models, but also for current policies on land use intended to encourage fungi, which they think may be based on flawed assumptions about the role of fungi in reducing environmental damage.

New models

But they cannot say precisely what the significance of their findings may prove to be for greenhouse gases. Dr Rousk told the Climate News Network: Current models for carbon and nutrient turnover used by the IPCC, for example, and other organisations offering advice to governments do not yet explicitly incorporate microbial communities.

A new generation of models is under development that have begun to do this. These will be affected by our results, which challenge current beliefs held in soil microbial ecology.

So our results will not directly affect current models or their predictions, but the development of next generation models. It is probably not possible to conclude whether the models in use today have led to over-estimates of releases, or the opposite.

By revising the interpretation of fungal and bacterial roles in decomposition, and their potential for carbon and nutrient release from soils, our results will hopefully reduce the ‘noise in the models and increase the precision of predictions.

Decomposition and other soil processes are estimated to account for nearly 30% of all naturally-produced CO2 emissions. – Climate News Network

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China’s carbon count is not as high as feared

China’s carbon count is not as high as feared

The use of poor-quality coal in Chinese power plants means that the carbon dioxide emissions of the world’s biggest polluter are 10% less than previously thought.

LONDON, 21 August, 2015 – Calculations on how much carbon dioxide China produces have been wrong for more than 10 years because the official bodies that calculate it have assumed the country’s power stations burn high-quality coal.

In fact, the world’s biggest polluter uses coal with a lower carbon content than power stations in Europe and the US, and so produces less carbon dioxide per tonne − around 14% less according to experts from 18 research institutions.

Getting the total quantities of CO2 emitted by each country correct is crucial if the world is going to reach agreement on tackling dangerous climate change at the UN conference in Paris in December. One of the stumbling blocks to agreements in the past has been politicians’ need to have a fair system of sharing the burden of cuts.

Calculating how much pollution each country produces has been largely based on the quantities of fossil fuels burned in electricity and heat production and in motor vehicles.

This has not taken into account the fact that the amount of carbon in coal and oil varies according to its quality, and so an average figure has been used, which turns out to be unfair in the case of China.

Appalling air quality

One of the ironies of the finding is that while the carbon content of the coal may be less, its impurities means it emits more of other kinds of pollution. This is what has made air quality in Chinese cities so appalling, and has started a big debate in China about whether the country should seek to burn better-quality coal to avoid killing its citizens with bad air.

The revised estimates of China’s carbon emissions, published in the journal Nature, were produced by an international team, led by researchers from Harvard University, the University of East Anglia (UEA), in England, the Chinese Academy of Sciences and Tsinghua University, in collaboration with 15 other international research institutions.

The team re-evaluated emissions from the burning of fossil fuels and cement production from 1950 to 2013. They used independently-assessed activity data on the amounts of fuels burned, and new measurements of emissions factors – the amount of carbon oxidised per unit of fuel consumed – for Chinese coal.

Because the amount of coal burned in China is so vast, the size of the error is also huge. It means there are 2.9 fewer gigatonnes of carbon in the atmosphere. That is more than the total amount of carbon stored by China’s forests over roughly the same period.

“Evaluating progress towards countries’ commitments to reduce CO2 emissions depends upon improving the accuracy of annual emissions estimates”

It is particularly important because nearly three-quarters of the growth in global carbon emissions from the burning of fossil fuels and cement production between 2010 and 2012 occurred in China.

The lead UK researcher, Prof. Dabo Guan, of UEA’s School of International Development, said the key contributor to the new estimates was fuel quality, which for the first time was taken into consideration in establishing emission inventories – something the Intergovernmental Panel on Climate Change (IPCC) and most international data sources had not done.

“China is the largest coal consumer in the world, but it burns much lower quality coal, such as brown coal, which has a lower heat value and carbon content compared to the coal burned in the US and Europe,” Prof. Guan says.

“China is one of the first countries to conduct a comprehensive survey for its coal qualities, and a global effort is required to help other major coal users, such as India and Indonesia, understand their physical coal consumptions as well as the quality of their coal types.

“Our results suggest that Chinese CO2 emissions have been substantially over-estimated in recent years. Evaluating progress towards countries’ commitments to reduce CO2 emissions depends upon improving the accuracy of annual emissions estimates and reducing related uncertainties. These findings represent progress towards improving estimates of annual global carbon emissions.”

Total consumption

The discrepancy would have been even greater if China more accurately counted its coal consumption. According to researchers, total energy consumption was 10% higher between 2000 and 2012 than reported in China’s national statistics. However, even taking that into account, emissions were still less than previously believed because emissions per tonne were on average 40% lower than the levels assumed by the IPCC.

This alters substantially the estimates of the Carbon Dioxide Information Analysis Centre (CDIAC) in the US and the Emissions Database for Global Atmospheric Research (EDGAR) in the EU, which are the official data sources for the IPCC Fifth Assessment Report (AR5) – providing scientific evidence for the climate change policy negotiations in Paris later this year.

The figure is also about 10% less than the estimate given for China in the most recent publication of the Global Carbon Project, which annually updates global carbon emissions and their implications for future trends.

Prof. Corinne Le Quéré, director of the Tyndall Centre for Climate Change Research at UEA, co-leads the publication of annual updates of emissions for the Global Carbon Project.

She says: “The strong message here is that as we refine our estimates of carbon emissions we get closer to an accurate picture of what is going on, and we can improve our climate projections and better inform policy on climate change.” – Climate News Network

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Carbon emissions threaten British butterflies

Carbon emissions threaten British butterflies

By mid-century carbon dioxide emissions in the United Kingdom could be causing recurrent droughts severe enough to force several butterfly species into extinction.

LONDON, 16 August, 2015 – If 25 years from now you can’t see a speckled wood near the English woodland, it wont be because of natural camouflage. And if you suddenly miss the large skipper, it wont be because it has led the team off the field.

Both species of British butterfly could be extinct because of global warming. And other flying insects, and even birds, may face similar jeopardy.

Under a range of climate change scenarios, extreme droughts are expected to become more frequent. Tom Oliver of the UK Centre for Ecology and Hydrology and colleagues report in the journal Nature Climate Change that they looked at long-term butterfly population records from 129 sites monitored under the UK Butterfly Monitoring Scheme to work out how 28 species had fared during an extreme drought event in Britain in 1995, and identified six species more than usually sensitive to brilliant sunshine and extended dry seasons.

Besides large skipper and speckled wood, these include the ringlet, large white, small white and green-veined white.

The authors warn that by 2050 the recurring droughts forecast by climate scientists under a “business as usual” scenario, in which humans go on expanding the use of fossil fuels, thus putting more and more of the greenhouse gas carbon dioxide into the atmosphere to raise global average temperatures, could cause population collapses.

Recovery impossible

“Should this occur repeatedly, populations may be unable to recover, resulting in local extinctions,” they warn.

The research was backed by the charity Butterfly Conservation, by the agency Natural England and by the University of Exeter.

Butterflies, transient and brightly coloured, make good tests of local ecological health, and so are well studied. So has been their response to climate change. Some species have responded by extending their range uphill or northwards in response to the overall shift in average temperatures, while other populations have dwindled.

A shift in climate is naturally expected to help some species flourish, others fade, But butterflies, like birds, are popular symbols of the natural world and there is pressure to conserve. The study is designed to examine the big challenges that will face conservation agencies by 2050.

“We consider the average response across Great Britain. Losses are likely to be more severe in drier areas with more intensive land use, whilst wetter areas with less fragmented habitat will provide refugia.

“The study looked at butterflies but the conclusions are potentially valid for other species”

“We assume that butterflies wont have time to evolve to become more drought-tolerant, because their populations are already small, and evolution would need to be very rapid. The study looked at butterflies but the conclusions are potentially valid for other species such as birds, beetles, moths and dragonflies,” said Dr Oliver.

Worryingly, the researchers found that simply devoting more space and habitat to conservation – and in a world in which rising population means greater pressure on farmland, this would not be easy – and especially by creating corridors along which species could migrate, would not be enough.

Even more worryingly, the scientists found that some species would be at risk of widespread extinction even under relatively favourable greenhouse emissions scenarios.

“The results are worrying. Until I started this research, I hadnt quite realised the magnitude and potential impacts from climate change,” said Dr Oliver. “For drought-sensitive butterflies, and potentially other taxa, widespread population extinctions are expected by 2050.

“To limit these losses, both habitat restoration and reducing CO2 emissions have a role. In fact, a combination of both is necessary.” – Climate News Network

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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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