US farmers given early warning about hungry crop pest

US farmers given early warning about hungry crop pest

Biologists say a destructive insect is likely to cause even more damage than usual as rising temperatures prompt leaves to sprout earlier.

LONDON, 24 May, 2015 − It is small, bright green and an unwelcome visitor. But global warming means that this particular agricultural menace arrives earlier than ever − and consumes more than ever.

New research has confirmed that the potato leafhopper now turns up to devour US crops on average 10 days earlier than it did 60 years ago.

Despite its informal name, Empoasca fabae is known to have developed an appetite not just for potatoes, but for anything from rhubarb to red maple trees.

It survives over the winter in the southernmost states, then moves north as the temperatures begin to rise and crops begin to sprout.

It has been observed to reproduce itself on around 200 plant species, and it also has a taste for apples, celery, beans, grapes, hops and the important perennial forage crop alfalfa, sometimes also known as lucerne.

Severe infestation

Three biologists from two US universities report in PLOS One, the Public Library of Science journal, that leafhopper infestation is more severe in the warmest years, and that the damage caused by the tiny insect is likely to increase as average temperatures continue to rise.

It arrives in the growing season and pierces the plant leaf tissue to get at the sap. Its saliva carries a toxin that can cause the leaf to dry, curl and rot, and the consequent damage is called “hopperburn”.

“You don’t realise they’re even there until you see the damage to the plants . . . By then it’s too late”

“Earlier arrival dates make it particularly important for farmers to get out early in the season and scout for leafhoppers,” says William Lamp, associate professor of entomology at the University of Maryland, and one of the three authors of the study.

“They’re tiny, flighty and very hard to see. You don’t realise they’re even there until you see the damage to the plants, which can take up to a week to manifest. By then it’s too late.”

The researchers combed the records between 1951 and 2012 to track the dates in which the pest was recorded in each of 19 affected US states, and matched this with weather records over the same timespan. Such a finding was  possible only because scientists had access to systematic data.

Dilip Venugopal, an ecologist, and colleague of Lamp at the University of Maryland, says: “The historical records on agricultural pests are a gold mine, made possible by decades of hard work by agricultural research and extension personnel who collect this data. There has been a decline in data collection activity over the past decade, and we would love to see an effort to ramp this up again.”

Global average temperatures have risen by 0.74°C since 1951, and the last decade has been the warmest since climate records began.

Changed behaviour

The leafhopper is only one of many long-distance migratory pests likely to change behaviour in response to climate change. Other researchers have already observed crop pests’ steady movement towards higher latitudes in recent decades.

“Climate change is not just costly because temperatures and oceans rise, but because it makes it harder to feed ourselves,” says report co-author Mitchell Baker, assistant professor of biology at Queens College, City University of New York.

“Increased pest pressure in agriculture is one of the complex effects of continued warming. Predicting arrival time and severity is critical to managing this pest and others like it.” – Climate News Network

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Climate impacts leave rainforests on edge of destruction

Climate impacts leave rainforests on edge of destruction

Eminent conservationist says climate change’s major threat to the world’s tropical rainforests comes not from heat, but from drought and uncertain rainfall.

LONDON, 23 May, 2015 – Rising temperatures will not themselves spell disaster for the world’s rainforests. It is the droughts and unpredictable rainfall patterns, which climate change is already worsening, that will settle the forests’ fate before the century ends, according to a new book.

Claude Martin, who has worked in tropical rainforest conservation since the 1970s, is author of On the Edge, commissioned by the Club of Rome, which published the seminal Limits to Growth report in 1972. Since then, nearly 50% of the world’s forest cover has disappeared.

Martin, a former director-general of WWF International, recognises that there are many drivers of forest damage and destruction − including the pressures of the global economy for animal feed and food for humans, and the worldwide demand for biofuels.

Essential ecosystem

Acknowledging the progress made in science and conservation, he reminds his readers that the forests are not just huge repositories of biodiversity, but an essential ecosystem providing everyone on the planet with fresh water, clean air and climate regulation.

Evaluating the impact of climate change on rainforests means focusing on the length of dry seasons and water stress, rather than temperature, Martin writes.

The likeliest cause of forest collapse and severe risks of reaching a tipping point is not temperature rise, but the change from the dependable rainfall patterns of the past, and the probability of increasing droughts and forest fires.

He sees a likelihood of drought and fires increasing − not least in the Amazon − because of the way in which climate change is fuelling El Niño and La Niña, the twin periodic temperature disruptions that occur every few years in the eastern Pacific Ocean.

Known together as the El Niño-Southern Oscillation (ENSO), their impacts spread for thousands of miles.

“Lethargy of governments and the impotence of the intergovernmental system make it very unlikely that average global warming will be kept below 2°C

Martin is one of those scientists who are convinced that climate change will intensify ENSOs. As global warming effects become stronger, ENSO events become more frequent, rainfall drops further because of forest loss and fragmentation, and droughts are likely to become more common and more severe. And so the vicious circle becomes a constant downward spiral.

“When the 20th century’s strongest ENSO occurred in 1997/98,” Martin writes, “it was considered to be an unusual phenomenon. . . . [It] caused severe drought in Amazonia, Southeast Asia and Mexico, and had massive effects on the net primary productivity of forests, thus their capacity of carbon storage as well as forest fires.”

After another severe drought in 2001, following another ENSO event, about a third of the Amazon forests stored significantly less carbon and became vulnerable to fire. Two more droughts followed soon after, in 2005 and 2010. The first was estimated to be a once-in-a-century occurrence.

Fastest warming

Martin’s concerns are not confined to Amazonia. He cites modelling by the Intergovernmental Panel on Climate Change, which shows that Africa is expected to warm by 3-4°C by the end of the century − the fastest warming since the end of the last ice age around 11,500 years ago. This would expose the great Congo Basin forest to the risk of severe damage.

Globally, Martin is not hopeful. “The current rate of greenhouse gas emissions, the lethargy of governments and the impotence of the intergovernmental system make it very unlikely that average global warming will be kept below 2°C,” he says.

Under a mid-range emissions scenario, atmospheric CO2 concentrations are likely to rise by the end of the century to levels not seen in the last 50 million years. But he thinks the forest crisis will be developing uncontrollably some decades before then.

He predicts: “The decisive period for the long-term future of the rainforests . . . will be the second half of the century, when global warming is likely to exceed 2°C above the pre-industrial global average.

“It will be too late then to avoid a dangerous tipping point of self-reinforcing climate change.” – Climate News Network

  • On the Edge − The State and Fate of the World’s Tropical Rainforests. A Report to the Club of Rome, by Claude Martin (Greystone Books, £20/US$32.95).

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Heat and drought pose threat to US power supplies

Heat and drought pose threat to US power supplies

Global warming will leave people in the western states of the US exposed to increasingly extreme temperatures that could seriously affect electricity generation.

LONDON, 22 May, 2015 – Climate change could mean that things get really tough for people in the US west in the second half of this century, according to new research.

Higher temperatures and increased intensity of droughts could compromise the electricity grid, while the number of people exposed to extremes of heat is likely to multiply at least fourfold, and perhaps more.

Sustainability scientists Matthew Bartos and Mikhail Chester, of Arizona State University, report in Nature Climate Change that changes in precipitation, air and water temperature, air density and humidity could combine to create problems for electricity generating plant in the western US.

They estimate that around 46% of the generating capacity in 14 US states could experience reductions of up to 3% in the next few decades.

Stream flow

That is because there may not be enough stream flow for hydroelectric stations, and coal and nuclear power plant may not be able to get enough water through the cooling systems to keep generating at peak capacity, especially in the summer months.

Gas turbines, wind turbines and solar cells also could be affected by changes in air temperature.

“Drought and heat-related capacity reductions are especially problematic, because they are likely to occur during periods of high demand,” the researchers warn.

“From 2001 to 2008, a series of droughts caused electricity shortages in the American  southeast, the Pacific  northwest, and continental Europe. As concentrations of atmospheric carbon increase, drought events are anticipated to increase in frequency, duration and intensity.”

“Power providers are not taking into account climate change impacts”

Research such as this is intended to help energy utilities plan for problems ahead. Scientists identify a worst-case scenario, outline the probable  difficulties, and prompt the engineers and managers to take steps to avoid future embarrassments.

As global temperatures rise on average in the coming decades – as carbon dioxide levels in the atmosphere increase with the continued use of fossil fuels – so regions such as the American southwest will experience greater extremes of heat and longer periods of drought.

This will mean that available water will have to be pumped further, and there will be greater demand for cooling and air-conditioning systems.

California and the US  southwest have already been in the grip of extended drought.

“Power providers are not taking into account climate change impacts,” Bartos says. “They are likely overestimating their ability to meet future electricity needs.”

Reduced capacity

The scientists calculated that – if a drought lasted for a decade – capacity in vulnerable power generating stations could be reduced by as much as 8.8%.

Meanwhile, Bryan Jones, a demographer at the City University of New York, and colleagues report in the same issue of Nature Climate Change that the number of people who will want to switch on the air conditioning in the second half of the century will increase dramatically.

“We find that US population exposure to extreme heat increases fourfold to sixfold over observed levels in the late 20th century, and that changes in population are as important as changes in climate in driving this outcome,” they report.

And they add a warning: “Extreme heat is responsible for more deaths in the United States than any other weather-related event, and its frequency and intensity is expected to increase over this century.” – Climate News Network

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Cutting warming to 1.5°C could put food supply at risk

Cutting warming to 1.5°C could put food supply at risk

Scientists say meeting the tougher demands of many countries on limiting global temperature rise may be technically feasible, but would risk worsening world hunger.

LONDON, 21 May, 2015 – As world leaders try to agree how to prevent global warming from heating the planet by more than 2°C above pre-industrial levels, scientists have tackled an altogether thornier question: can we keep the rise below 1.5°C?

The lower target − demanded by more than 100 countries as a safer goal − is attainable, they say. But there will be little room for error, and getting there will mean not only cutting greenhouse gas emissions, but actually removing carbon dioxide from the atmosphere.

That is not possible with the technology now available. And even if it could one day be done, it would probably have forbiddingly harmful consequences for world food supplies.

However, limiting temperature rise by 2100 to less than 1.5°C is still feasible, say the researchers from the International Institute for Applied Systems Analysis (IIASA) in Austria, the Potsdam Institute for Climate Impact Research (PIK), Germany, and colleagues. They report their findings in the journal Nature Climate Change.

Similar actions

Not surprisingly, the answer includes doing more, and doing it faster. “Actions for returning global warming to below 1.5°C by 2100 are in many ways similar to those for limiting warming to below 2°C,” says IIASA climate researcher Joeri Rogelj, one of the lead authors of the report.

The authors accept that the economic, political, and technological conditions for achieving even 2°C are “substantial”. The negotiations to be held in Paris in December by member states of the UN Framework Convention on Climate Change (UNFCCC) may show what chance there is of meeting them.

The new study identifies key ways of reaching the 1.5°C target by 2100. One is a tight limit on future carbon emissions.

Gunnar Luderer, PIK senior researcher in sustainable solutions, who co-led the study, says: “In 1.5°C scenarios, the remaining carbon budget for the 21st century is reduced to almost half, compared to 2°C scenarios.

“As a consequence, deeper emissions cuts are required from all sectors, and global carbon neutrality would need to be reached 10-20 years earlier than projected for 2°C scenarios.”

Energy efficiency will also need to improve faster, he says.

“The scenarios we assess keep warming
to the lowest levels currently considered
technologically feasible”

But the study finds that staying below 1.5°C would require a radical step change: some time this century, carbon emissions would have to become negative at a global scale.

That is the scientists’ way of saying that significant amounts of CO2 will have to be actively removed from the atmosphere. And there is at present no known way of doing that.

In theory, it is possible − for example, through bio-energy use, combined with carbon capture and storage. But that is a technology that so far remains untested on a large scale.

It would also increase hunger, as the crops needed to produce enough biofuel would compete for land with food plants.

Another idea is to grow more forests, which would sequester carbon in their trees, but this would be open to the same objection − that it would reduce cropland. The higher temperatures in prospect will themselves affect forest growth and health.

Lowest levels

Rogelj told the Climate News Network: “Increased temperatures can make afforestation efforts harder. However, the scenarios we assess here keep warming to the lowest levels currently considered technologically feasible, and this issue will thus have a relatively smaller impact.”

Whatever happens, the authors expect things to get hotter before they have any chance of cooling down.

Rogelj says: “Basically, all our 1.5°C scenarios first exceed the 1.5°C temperature threshold somewhere in mid-century, before declining to 2100 and beyond as more and more carbon dioxide is actively removed from the atmosphere by specialised technologies.”

Over 100 countries worldwide more than half the members of the UNFCCC, including the Alliance of Small Island States (AOSIS) and the Least Developed Countries (LDCs) have declared their support for a 1.5°C target. – Climate News Network

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First head of state backs campaign to save the planet

First head of state backs campaign to save the planet

Hungary’s president boosts an ambitious plan to collect a billion-signature petition aimed at pressuring politicians to agree on radical measures to tackle global warming.

BUDAPEST, 20 May, 2015 – János Áder, the President of Hungary, has become the first head of state to join the Live Earth: Road to Paris campaign that aims to ensure world leaders agree to a binding deal on tackling climate change.

The specific aim is to get a billion signatures from concerned citizens before the UN climate change conference in Paris in December, but organisers are also keen to get as many politicians and celebrities as possible to back the campaign.

The Road to Paris campaign was launched in January at the World Economic Forum in Davos, Switzerland, by former US vice-president Al Gore, songwriter and recording artist Pharrell Williams, and the Emmy award-winning producer and new media entrepreneur, Kevin Wall.

Global voices

Williams, winner of 11 Grammy awards, is Live Earth’s creative director, and music concerts will be staged in Paris, New York, Johannesburg, Sydney, São Paulo and Beijing on June 18, seeking to reach two billion people in 190 countries and unite global voices in demanding environmental accountability from world leaders.

Áder, a former member of the European Parliament’s Committee on the Environment, Public Health and Food Safety, endorsed the campaign at a press briefing in Budapest earlier this month.

Praising Gore’s initiative, Áder talked about the evidence of climate change, available solutions, the positive impacts of green technologies, and the challenges and opportunities of the Paris conference in December.

A spokesperson for Gore told the Climate News Network that the agreement in Paris should involve meaningful emissions reductions commitments at the national level, subject to a system of periodic review, and a long-term goal of net zero-carbon emissions.

Planet-wide shift

A Hungarian website that mirrors the US initiative will seek to encourage widespread local demand for a strong agreement that will dramatically cut emissions and accelerate the planet-wide shift to clean energy, said Zsolt Bauer, of the Hungary-based Regional Environmental Centre (REC).

The REC was instrumental in setting the scene for Áder’s announcement, in partnership with the Climate Reality Project, chaired by  Gore.

Áder has committed to speaking and broadcasting in Hungary to promote the petition, and to raising awareness of the available climate solutions, backed by  the REC nationally and regionally. − Climate News Network

  • Pavel Antonov, a Budapest-based journalist and social researcher, edits Evromegdan.bg, a not-for-profit online magazine for journalism in the public interest, published by BlueLink.net

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Pakistan turns desert into a sea of solar panels

Pakistan turns desert into a sea of solar panels

Economic links with China help Pakistan tap into enormous solar energy potential that can provide clean power to boost production and reduce poverty.

ISLAMABAD, 19 May, 2015 – One of the world’s largest solar plants has been opened in Pakistan with the aim of supplying clean, reliable energy and helping alleviate the country’s chronic power shortages.

The plant, spread over more than 200 hectares of desert land in the south of Pakistan’s Punjab province, will generate 100 megawatts (MW) in its initial phase and more than 300MW by the end of the year, according to government officials.

More than a third of Pakistan’s population do not have access to electricity, and power shortages are a serious impediment to economic growth.

Inaugurating the plant, Nawaz Sharif, Pakistan’s prime minister, said: “Since I became prime minister, my one goal has been to eliminate darkness in Pakistan and bring lights back to the country.”

Mushahidullah Khan, the Federal Minister for Climate Change, told the Climate News Network that the government is determined to make use of what it sees as the country’s enormous solar energy potential.

Energy crisis

He said: “Tackling our energy crisis is the top priority of the present government as we believe it is vital in order to achieve economic growth, alleviate poverty, boost agricultural and industrial production and – through the provision of clean, solar power – reduce the country’s carbon footprint.”

The plant – called the Quaid-e-Azam Solar Power Park – was constructed in less than a year by China’s Tebian Electric Apparatus Stock Company, at a cost of US$131 million.

“Solar energy is especially suited to remote areas in the country where connectivity to the national grid is difficult”

China has been forging ever closer economic links with Pakistan as part of a plan to link China’s western Xinjiang region to the Pakistan port of Gwadar on the Arabian Sea. The government in Islamabad says China is likely to invest more than $30 billion in solar and other power projects in Pakistan in the coming years.

At present, more than 60% of Pakistan’s power is generated from oil and gas, and about 30% from hydro power.

Pakistan is considered to be one of the countries in the Asia-Pacific region most vulnerable to the impacts of climate change.

Erratic flow

In particular, the flow of water in the Indus river – upon which millions depend for hydro power and for irrigating crops – has become increasingly erratic due to changing rainfall patterns, glacial melt in the western Himalayas region, and the impact of widespread deforestation.

Government officials say they are determined to push ahead with more solar and wind projects throughout the country.

Asjad Imtiaz Ali, chairman of Pakistan’s Alternative Energy Development Board, said the development of solar and other renewable energies was hampered in the past by inconsistencies in government policy, and by a lack of understanding of clean energies.

“Solar energy is especially suited to remote areas in the country where connectivity to the national grid is difficult, such as Punjab, Baluchistan and Sindh provinces,” he said.

As part of the push for more solar projects, the government recently announced the abolition of duty on the import of solar panels. − Climate News Network

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Antarctic ice is under attack from sea and air

Antarctic ice is under attack from sea and air

Satellite and radar studies show that twin forces causing the vast ice shelf to thin and become less stable could have a serious impact on global sea levels.

LONDON, 18 May, 2015 − Scientists have measured the rate of thinning of the great sea ice shelf of the Antarctic Peninsula and have identified the mechanisms at work above and below the shelf.

The collapse of floating sea ice makes no direct difference to global sea levels – but the effects could nevertheless lead to higher waters everywhere.

Paul Holland, of the British Antarctic Survey (BAS), and research colleagues from the US report in the journal The Cryosphere that they used satellite measurements and radar studies between 1998 and 2012 to confirm that the Larsen C ice shelf has lost four metres of ice, and is a metre lower at the surface.

Warmer waters

This is the largest of three shelves that have been under study for decades; the Larsen A and Larsen B shelves have already broken off and drifted north to warmer waters.

The Antarctic Peninsula is one of the fastest-warming regions of the world: 2.5°C in the last 50 years.

“What’s exciting about this study is we now know that two different processes are causing Larsen C to thin and become less stable,” says Dr Paul Holland, lead author of the BAS study.

“Air is being lost from the top layer of snow (called the firn), which is becoming more compacted, probably because of increased melting by a warmer atmosphere.

“We expect that sea-level rise around the world will be something in excess of 50 cm higher by 2100 than it is at present”

“We know also that Larsen C is losing ice, probably from warmer ocean currents or changing ice flow. If this vast ice shelf − which is over two and a half times the size of Wales, and 10 times bigger than Larsen B − was to collapse, it would allow the tributary glaciers behind it to flow faster into the sea. This would then contribute to sea-level rise.”

A collapse of the shelf could occur within a century. When the two companion Larsen glaciers broke away, the glaciers that flowed from the ice-capped continent towards the sea began to accelerate.

Offshore ice, held fast to the shoreline, is a factor that helps keep glacier flow at its proverbially glacial pace. Once it has gone, the frozen rivers of ice onshore naturally begin to flow faster.

“We expect that sea-level rise around the world will be something in excess of 50 cm higher by 2100 than it is at present, and that will cause problems for coastal and low-lying cities,” says David Vaughan, director of science at the BAS.

“Understanding and counting up these small contributions from Larsen C and all the glaciers around the world is very important if we are to project, with confidence, the rate of sea-level rise into the future.”

The study is a confirmation of earlier research in which other groups, using different approaches, have already identified shelf ice loss and have warned that Antarctic melting could accelerate. Satellite-based measurements have also linked glacial melting with an acceleration in sea level rise.

Precision measurement of sea level rise is not easy. Oceans rise and fall with the tides, the water isn’t level anyway, and salinity and temperature differences in the oceans, and gravitational anomalies in the ocean basins, all mean that the ocean surfaces naturally undulate.

And the continents don’t keep still. Land surfaces from which researchers base their measurements also slowly rise or fall.

Accelerated rise

Christopher Watson, senior lecturer in the School of Land and Earth at the University of Tasmania, Australia, and colleagues report in Nature Climate Change that a different approach to the problem suggests that – contrary to previous estimates – sea level rise has accelerated in the last decade.

He and his colleagues searched not just global positioning satellite evidence from the surface waters but also from the land for signs of “bias” in the data. They also used evidence from hourly tide gauges from around the world and recalculated the rate of change.

What they found was that, overall, sea level rise in the last two decades has been at a rate just under, rather than just over, 3mm a year.

But the overestimate for the first six years of the survey had been much higher, which in turn suggested that the rate of rise had actually accelerated during this century, in a way that is consistent with the rate of glacial melting − at least from the Greenland and West Antarctic ice caps. – Climate News Network

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Earth wins time as land and seas absorb more carbon

Earth wins time as land and seas absorb more carbon

Climate change has intensified more slowly than scientists had expected because the continents and oceans are absorbing more atmospheric carbon dioxide.

LONDON, 17 May, 2015 − Half of all the carbon emissions from burning fossil fuels remain in the atmosphere. The good news is that only half remain in the atmosphere, while the rest have been taken up by the living world and then absorbed into the land, and the ocean. That is, as carbon dioxide levels in the atmosphere have risen, so also has the planet’s capacity to soak up atmospheric carbon.

The implication is that what engineers call “positive feedback” – in which global warming triggers the release of yet more greenhouse gases into the atmosphere to accelerate yet further warming – doesn’t seem to be at work yet.

The implication, too, is that the world’s governments still have time to launch determined programmes to sharply reduce fossil fuel use, and switch to wind, solar and other renewable energy sources before climate change disrupts the planet’s food security and exacts what could be a devastating toll on the biosphere.

But most climate scientists know all this anyway: the real significance of a new study in the journal Biogeosciences is that US and British scientists have narrowed some of the uncertainties in what climate scientists like to call the carbon budget: how much gets into the atmosphere, where it goes, and how long it stays.

That is because although the big picture – that carbon dioxide levels in the atmosphere are beginning to rise steeply – has been confirmed repeatedly by systematic measurements since 1956, the potential margin of error has been considerable.

“This increased uptake by land and ocean is not only surprising; it’s good news”

“There is no question that land and oceans have, for at least the last five and half decades, been taking up about half of the carbon emitted each year. The outstanding question is, Why?” said Richard Houghton of the Woods Hole Research Center in Massachusetts, one of the authors.

“Most of the processes responsible for that uptake would be expected to slow down as the Earth warms, but we haven’t seen it yet. Since the emissions today are three times higher than they were in the 1960s, this increased uptake by land and ocean is not only surprising; it’s good news.

“Without it, the concentration of CO2 in the atmosphere would be twice what it is, and climate change would be much farther along. But there’s no guarantee that it will continue.”

The carbon budget is an integral part of the climate puzzle: all simulations of how climate will change with increasing emissions from fossil fuels depend on an understanding of how much carbon dioxide concentrates in the atmosphere and what happens to it after that.

In the last few months researchers have reported a dramatic uptake of atmospheric carbon by new forests and the growth of woodland on the world’s savannahs and pinpointed the fjords – those steep, still stretches of sea in mountainous coastlines in the high latitudes – as prime “sinks” for atmospheric carbon.

Uncertainties narrowed

At the same time others have once again confirmed fears that thawing permafrost could release vast quantities of carbon stored for millennia is semi-decayed and now frozen vegetation.

But these have been studies of small pieces of the big puzzle. What the Biogeosciences authors did was to refine two global uncertainties. One is how much fossil fuel is burned each year and the other is how much is stacking up in the atmosphere.

Both sound simple, but the first question is complicated by differences in the ways nations maintain their own energy inventories, and the way they report the details, and the second depends on how the use of land has changed, how the oceans are responding to higher levels of acidification and how carbon dioxide levels vary according to region, and to season.

With greater certainty in the answers to the second question – which began with one single set of measurements at the top of a mountain in Hawaii now replicated worldwide – researchers found they could make more sense of the first question, and narrow the uncertainties to a point where they could write that they were “93% confident that terrestrial C uptake has increased and 97% confident that ocean C uptake has increased in the last five decades.

“Thus it is clear that arguably one of the most vital ecosystem services currently provided by the biosphere is the continued removal of approximately half of atmospheric CO2 emissions from the atmosphere.” − Climate News Network

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Deniers’ voices try to drown out climate scientists

Deniers’ voices try to drown out climate scientists

New study indicates that loud dissent from contrarians may prompt some researchers to soften their language about the threats of climate change.

LONDON, 16 May, 2015 − Climate change denial by contrarians claiming that global warming has stopped, is a natural cycle rather than a consequence of human action, or is simply a hoax or conspiracy can take its toll of climate scientists too.

A new study in Global Environmental Change suggests that the loudest voices of dissent can affect the way researchers who have separately and repeatedly confirmed the reality of global climate change then talk about their own research.

Scoffing by contrarian voices can lead researchers to over-emphasise the inevitable scientific uncertainties, or over-react to claims of alarmism, or even adopt some of the contrarian language – chief of which has been talk of a “pause” or “hiatus” in global warming in the 21st century.

Psychological mechanisms

Stephan Lewandowsky, professor at the University of Bristol School of Experimental Psychology in the UK, and colleagues from the US and Australia call the problem “seepage”. That is, the language of the contrarians has seeped into scientific discourse.

The researchers identify three psychological mechanisms, which they call “stereotype threat”, “pluralistic ignorance” and “third-person effect”.

The first acts as a behaviour response: stereotype climate scientists as alarmist and this triggers a natural reaction to avoid the stereotype and downplay the climate threat, or at least not highlight the risks.

“The public has a right to be informed of risks,
even if they are alarming”

Pluralistic ignorance follows when a noisy minority opinion gets disproportionate play in public debate − that is, when people who thought they were in a majority begin to feel inhibited.

The third-person effect is the assumption that persuasive communications might persuade other people, but not the experts. In fact, there is evidence that even experts can be subtly affected by such talk.

Professor Lewandowsky says: “It seems reasonable to conclude that the pressure of climate contrarians has contributed, at least to some degree, to scientists examining their own theory, data and models, even though all of them permit – indeed expect – changes in the rate of warming over any arbitrarily chosen period.

“We scientists have a unique and crucial role in public policy to communicate clearly and accurately the entire range of risks that we know about. The public has a right to be informed of risks, even if they are alarming.

“Climate scientists have done a great job in pursuing their science under great political pressure, and they have tirelessly rebutted pseudoscientific arguments against their work.

“However, sometimes scientists have inadvertently allowed contrarian claims to frame the language of their scientific thinking, leading us to overstate scientific uncertainty and under-communicate knowledge.”

A second study by US scientists recently confirmed that, in fact, scientists have communicated the knowledge. They have certainly done so to a US legislature rich in Republican representatives who make a point of challenging or dismissing the climate science consensus.

Contrarian voices occasionally claim that the scientific community is “divided” − but such division was not on show in evidence presented to the US Congress.

Expert witnesses

Xinsheng Liu, associate research scientist at Texas A&M University, and colleagues report in the journal Climatic Change that they analysed 1,350 testimonies delivered to 253 congressional hearings from 1969 to 2007.

Of the expert witnesses who expressed a view, 86% said that climate change was happening, and 78% said it was a consequence of human activity. Most significantly, 95% of those scientists who gave testimony supported action to combat climate change.

So a “supermajority” of scientific opinion had presented the facts to Congress, and the near-complete agreement in the science community had been consistently presented.

“Possible explanations for policymakers’ contention must be based on something other than a lack of knowledge or divided scientific information,” the report’s authors conclude. – Climate News Network

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Weather events taken to extremes by climate change

Weather events taken to extremes by climate change

Scientists warn that global warming could greatly increase the likelihood of droughts, floods and heatwaves reaching record levels of frequency and intensity.

LONDON, 15 May, 2015 − As temperatures soar to record heights, blame it on global warming − but only about three-quarters of the time. And when the rain comes down by the bucketful, you can attribute one downpour in five to climate change.

Yet another team of research scientists has looked at the probabilities, and has linked extremes of weather with global warming.

Extremes have always happened and are, by definition, rare events. So, for the last 30 years, climate scientists have carefully explained that no particular climate event could be identified as the consequence of a rise in global average temperatures driven by the release of carbon dioxide and other greenhouse gases from the burning of fossil fuels.

But some events that were once improbable have now become statistically more probable because of global warming, according to Erich Fischer and Reno Knutti, climate scientists at ETH Zurich − the Swiss Federal Institute of Technology.

They report in Nature Climate Change that they looked at simulations of probabilities and climate records for the period 1901 to 2005, and projections for the period 2006 to 2100.

Rise in temperatures

Then they settled down to calculate the likelihood that a proportion of past heatwaves or floods could be linked to a measured average rise in planetary temperatures so far of 0.85°C.

They worked out how these proportions would change if the average planetary temperatures reach 2°C above the “normal” of the pre-industrial world, and they found that human-induced global warming could already be responsible for 18% of extremes of rain or snow, and 75% of heatwaves worldwide.

If the temperatures go up to the 2°C that nations have agreed should be the limit, then the probability of precipitation extremes that could be blamed on global warming rises to 40%. They are less precise about heatwaves, but any rise could be sharp.

“If temperatures rise globally by 2°C, we would expect twice as many extreme heat events worldwide than we would with a 1.5% increase,” Dr Fischer says.

“These global warming targets, which are discussed in climate negotiations and which differ little at first glance, therefore have a great influence on the frequency of extremes.”

The researchers are talking about probabilities: it will still be difficult ever to say that one event was a random happening, and another a result of climate change. In such research, there are definition problems. What counts as extreme heat in northern England would not be extreme in India or Saudi Arabia.

But such distinctions could become increasingly academic for people who live in the path of unusual heat and extended drought, or flash floods and catastrophic hailstorms.

A scientist recently told the European Geosciences Union that some regions of the planet will see unprecedented drought, driven once again by climate change, before 2050.

Ignored warnings

Yusuke Satoh, of the International Institute for Applied Systems Analysis, warned that under the notorious business-as-usual scenario −where nations ignore such warnings and just go on burning fossil fuels − 13 of 26 global regions would see “unprecedented hydrological drought levels” by 2050. Some would see this parching much earlier − the Mediterranean by 2027, and the western US as early as 2017.

Such studies are calculated to help provoke governments, states and water authorities into preparing for climate change, but it just may be that the western US is already feeling the heat. California, in particular, has been in the grip of unprecedented drought, and researchers have already linked this to climate change.

Reservoirs and irrigation systems are built on historical data. “But in the next few decades, these historical data may no longer give us accurate information about current conditions,” Dr Satoh says. “The earlier we take this seriously, the better we will be able to adapt.” – Climate News Network

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