Stress on water resources threatens lives and livelihoods

Stress on water resources threatens lives and livelihoods

Satellite data raises red-flag warning about the draining of underground aquifers to meet the demands of expanding populations.

LONDON, 29 June, 2015 – The planet’s great subterranean stores of water are running out – and nobody can be sure how much remains to supply billions of people in the future.

Satellite instruments used to measure the flow from 37 underground aquifers between 2003 and 2013 have revealed that at least one-third of them were seriously stressed – with little or almost no natural replenishment.

The research was conducted by scientists from California and the US space agency NASA, who report in the journal Water Resources Research that they used data from NASA’s Gravity Recovery and Climate Experiment (GRACE) satellites to calculate what is happening to aquifers.

The two satellites measure variations in the gravitational pull of the planet’s surface, and have already revealed changes in the mass of ice sheets on the planetary surface. But buried water, too, has mass, and changes in the mass of bedrock in known aquifer regions would therefore offer a guide to depletion.

Driest regions

Not surprisingly, the researchers found that those regions that are already driest were drawing most heavily on the groundwater below the surface.

The Arabian aquifer system, − the principal water source for 60 million people − is the worst stressed, followed by the Indus Basin of north-west India and Pakistan, and then the Murzuk-Djado basin in northern Africa.

The scientists warn that climate change – a consequence of increasing atmospheric carbon dioxide emissions from the human combustion of fossil fuels – and population growth will make things worse.

“What happens when a highly-stressed aquifer is located in a region with socioeconomic or political tensions that can’t supplement declining water supplies fast enough?” asks Alexandra Richey, who conducted the research as a University of California Irvine doctoral student. “We’re trying to raise red flags now to pinpoint where active management today could protect future lives and livelihoods.”

“We can no longer tolerate this level of uncertainty, especially since groundwater
is disappearing so rapidly”

Her colleague, hydrologist James Famiglietti, identified his own home state of California as a cause for concern because it is in the grip of an extended drought that threatens agriculture.

“As we’re seeing in California right now, we rely much more heavily on groundwater during drought,” he says. “When examining the sustainability of a region’s water resources, we absolutely must account for that dependence.”

Groundwater accumulates slowly in the underlying bedrock over millennia. There is no problem if it is withdrawn slowly, but human population has exploded threefold in one human lifetime, and water use has risen even faster.

Supply problem

Research like this is a demonstration of ways to address a supply problem − but there is more work to be done.

In a second study in Water Resources Research, the same team examined the challenge of trying to calculate the rates at which aquifers are being emptied, and the uncertainties as to how much might remain in them.

In the Northwest Sahara, for instance, estimates of the projected “time to depletion” varied from 10 years to 21,000 years. “In a water-scarce society,” Richey says, “we can no longer tolerate this level of uncertainty, especially since groundwater is disappearing so rapidly.”

Professor Famiglietti concludes: “I believe we need to explore the world’s aquifers as if they had the same value as oil reserves. We need to drill for water in the same way that we drill for other resources.” – Climate News Network

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Combating climate dangers is seen as medical emergency

Combating climate dangers is seen as medical emergency

International experts say the last 50 years of health advances worldwide will be jeopardised unless urgent steps are taken to confront climate change.

LONDON, 23 June, 2015 – The threat that climate change poses to human health is so great that it could undermine the last half-century of gains in development and global health, says an international commission of medical experts.

One author, fiercely critical of international efforts to confront the problem, says it is a medical emergency that demands an emergency response.

More hopefully, though, the group’s report says that international efforts to tackle climate change – “the defining challenge of our generation” – represent one of the greatest opportunities to improve health worldwide this century.

The report, published in The Lancet medical journal, is the work of the 2015 Lancet Commission on Health and Climate Change.

Unparalleled chance

It says many responses to climate change have direct and indirect health benefits – from reducing air pollution to improving diet – and so efforts to reduce the threat offer an unparalleled chance for far-reaching gains in health.

But the commission is under no illusions about what is at stake. The authors say the potentially catastrophic risk to human health posed by climate change has been underestimated

They add – in a familiar refrain – that while the technologies and finance required to address the problem do exist, the global political will to implement them is lacking.

Professor Hugh Montgomery, one of the commission’s co-chairs and director of the University College London (UCL) Institute for Human Health and Performance, UK, says: “Climate change is a medical emergency. It thus demands an emergency response, using the technologies available right now.

“Under such circumstances, no doctor would consider a series of annual case discussions and aspirations adequate, yet this is exactly how the global response to climate change is proceeding.”

“Now is the time for us to lead the way in responding to another great threat to the human and environmental health of our generation

Lancet Commission on Health and Climate Change

Image: The Lancet Commission on Health and Climate Change

Professor Anthony Costello, another of the commission’s co-chairs and director of the UCL Institute for Global Health, says: “Climate change has the potential to reverse the health gains from economic development that have been made in recent decades – not just through the direct effects on health from a changing and more unstable climate, but through indirect means such as increased migration and reduced social stability.”

The report says the direct health impacts of climate change come from the increasing frequency and intensity of extreme weather events, especially heatwaves, floods, droughts and storms. Indirect impacts result from changes in infectious disease patterns, air pollution, food insecurity and malnutrition, involuntary migration, displacement and conflicts.

It says there are many ways in which action on climate change brings immediate health gains. For example, burning fewer fossil fuels reduces respiratory diseases, and what doctors call “active transport” (walking and cycling) cuts pollution and traffic accidents, and reduces rates of obesity, diabetes, coronary heart disease and stroke. There are also health benefits from changes to diet, such as eating less red meat.

Entrenched interests

The commission is an extensive collaboration between experts from Europe and China. Its other co-chair, Professor Peng Gong, from Tsinghua University, Beijing, says: “The health community has responded to many grave threats to health in the past.

“It took on entrenched interests such as the tobacco industry, and led the fight against HIV/AIDS. Now is the time for us to lead the way in responding to another great threat to the human and environmental health of our generation.”

The report provides a set of recommendations for policy-makers, and the authors propose the formation of a new global independent body on climate change and health − to be called Countdown to 2030: Climate Change and Health Action − to monitor and report every two years on the health impacts of climate change. – Climate News Network

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Rise in CO2 could restrict growing days for crops

Rise in CO2 could restrict growing days for crops

While plants in temperate zones may benefit from higher temperatures, global warming’s impact in the tropics threatens catastrophe for food security.

LONDON, 20 June, 2015 − The positive consequences of climate change may not be so positive. Although plants in the colder regions are expected to thrive as average global temperatures rise, even this benefit could be limited.

Some tropical regions could lose up to 200 growing days a year, and more than two billion rural people could see their hopes wither on the vine or in the field. Even in  temperate zones, there will be limits to extra growth.

Plants quicken, blossom and ripen as a response to moisture, warmth and the length of daylight. Global warming will clearly change the temperatures and influence the patterns of precipitation, but it won’t make any difference to the available hours of sunlight at any point on the globe.

Scientists at the University of Hawaii at Mānoa report in the Public Library of Science journal PLOS Biology that they looked at the big picture of complex change. Higher concentrations of atmospheric carbon dioxide – the greenhouse gas from car exhausts, forest fires and factory chimneys – are expected overall to aid crop and forest growth.

Extended season

Average global warming of less than 1°C in the last 30 years has extended the northern hemisphere growing season by up to 11 days, but plants are still limited by radiation.

“Those that think climate change will benefit plants need to see the light, literally and figuratively,” says Camilo Mora, lead author of the report and assistant professor in the Department of Geography at the University of Hawaii.

“A narrow focus on the factors that influence plant growth has led to major underestimations of the potential impacts of climate change on plants, not only at higher latitudes but more severely in the tropics, exposing the world to dire consequences.”

Professor Mora has made a career of thinking about global consequences. He and colleagues recently tried to calculate the possible dates at which local climates could shift inexorably in different parts of the world, and tried also to build a picture of how ocean warming and acidification would affect incomes everywhere.

“Many plants will not be able to take advantage of those warmer temperatures because there will not be enough sunlight to sustain their growth”

His team is not the first to try to calculate the potential impact of catastrophic global warming on global food supply. Cereals are vulnerable to extremes of heat, and climate change may already be affecting yields in Europe.

But the Hawaiian scientists tried a simple theoretical approach, by first identifying the ranges of temperature, soil moisture and light that drive 95% of the world’s plant growth today.

They then tried to calculate the number of days in a year in which these growth conditions could be expected at various latitudes in the future, as carbon dioxide levels – and average temperatures – climb.

They found that, nearer the poles, the number of days above freezing would increase by 7%.

“But many plants will not be able to take advantage of those warmer temperatures because there will not be enough sunlight to sustain their growth,” says Iain Caldwell, of the Hawaii Institute of Marine Biology.

The same warming at the lowest latitudes could be devastating: in some tropical regions, conditions could become too hot and dry for any growth.

Overall, the planet could see an 11% reduction in the number of days suited to growth, and some places in the tropics could lose 200 growing days a year.

Although some regions in China, Russia and Canada will see an improvement, around 2.1 billion people who rely on forests and agriculture for food and revenue could lose 30% of the days they now bank on for plant growth.

But rising levels of carbon dioxide could also affect the quality of plant growth, according to a new study in Global Change Biology.

Zhaozhong Feng, of the Department of Biological and Environmental Sciences at the University of Gothenburg, Sweden, and colleagues looked at the results of eight experiments in four continents on crops, grasslands and forests, and found that as carbon dioxide levels go up, the nitrogen content of the crop is lowered. In the case of wheat and rice, this would also mean lower protein levels.

Negative effect

“Furthermore, we can see that this negative effect exists regardless of whether or not the plants’ growth increases, and even if fertiliser is added,” says Johan Uddling, a plant physiologist at Gothenburg, and a co-author of the report. “This is unexpected and new.”

In the same week, a team of scientists at the University of Alaska Fairbanks produced evidence that climate change has already begun to alter the forests of the far north.

They report in the journal Forest Ecology and Management that in the interior of Alaska, already at the optimum temperature range for white spruce, tree growth slowed as summer temperatures rose.

In Western Alaska, once at the low end of the ideal temperature range for the same species, trees are now growing more rapidly.

“For the first time across a major forest region, we have real data showing that biome shift has started”, said Glenn Juday, professor of forest ecology at the university’s School of Natural Resources.

“This is not a scenario model, or a might, or a maybe. The boreal forest in Interior Alaska is very near dying from unsuitably warm temperatures. The area in Western Alaska where the forest transitions to tundra is now the productive heart of the boreal forest.” − Climate News Network

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India blames heatwave deaths on climate change 

India blames heatwave deaths on climate change 

Fierce temperatures in India doubled the heat-related deaths normally recorded in May − and the government insists natural causes are not to blame.

CHENNAI, 19 June, 2015 − India, one of the key players in the efforts to reach an international agreement on global warming, has no doubt of its malign effects. It was, says a government minister, the warming climate that caused last month’s devastating heatwave.

From mid-April till the end of May, nearly 2,200 people were killed by the heat − 1,636 of them in Andhra Pradesh, the worst-affected state. The normal May figure for the whole of India is about 1,000 heat-related deaths.

Dr Harsh Vardhan, India’s Minister of Science and Technology and Earth Sciences, has blamed the heat deaths squarely on climate change.

Improve understanding

Launching a supercomputer at the National Centre for Medium Range Weather Forecasting to improve understanding of climatic changes, he said: “It’s not just another unusually hot summer − it is climate change.

“Let us not fool ourselves that there is no connection between the unusual number of deaths from the ongoing heatwave and the certainty of another failed monsoon.”

Dr Vardhan said that May’s heatwave, followed by the delay to the start of the monsoon, on which nearly half of India’s farmlands depend, was a definite manifestation of climate change.

Jejabba, a 63-year-old farmer in Andhra Pradesh state, was one of those who lost their lives because of this year’s scorching heat.

He took his cows out to graze in a mango grove near his house around 11am, but was tired and dehydrated when he returned home four hours later. After he began vomiting, and then fainted, he was rushed to the small government hospital 5km from his village, but died on the way.

“In my 17 years of service, I have not
come across such an alarming number
of deaths due to a heatwave”

“Summer is severe, and many people have been affected by the heatwave in our village,” says Jejabba’s distant cousin, Pindigi Ramamurthi, who runs a grain store in the village. “Just the previous day, we took our two children to hospital after they began vomiting. The doctor admitted them for a few hours to administer fluids, and luckily that revived them.”

Local officials recorded Jejabba as “the latest of the summer deaths”. But when his widow asked for compensation − the state government pays 100,000 rupees (US$1,570) to the family of a victim − the local panchayat (civic) official, who has to recommend the payment, told her she must get a certificate from the hospital doctor.

“The doctor told the family he could not give the certificate because Jejabba did not die in his hospital,” Ramamurthi recalls. “Why couldn’t the poor fellow have stayed alive just an hour or so longer till we reached the hospital? Now the widow must suffer this red tape.”

In parts of southern India, daytime temperatures reached between 45° and 47°C during this year’s heatwave − up to 7°C above normal.

Alarming number

Dr Srihari Rao, resident medical officer at the government general hospital in Tirupati, about 45km from Jejabba’s home, says: “In my 17 years of service, I have not come across such an alarming number of deaths due to a heatwave.

“Almost every day in May there was a death in the district from sunstroke. The majority of the dead were in the 65 to 80 age group, but there was also a case of a 19-year-old girl dying from dehydration.”

Dr Rao said infants, aged people and farmers had been particularly severely affected.

The Intergovernmental Panel on Climate Change reported last year that there would be significant changes in the frequency and intensity of extreme weather events, including heatwaves in India. Its report was based on weather records from 1906 to 2005.

Researchers at the India Meteorological Department, after conducting a study of heatwaves over the last 50 years, have called for public information campaigns to be launched on the dangers, and also stressed the importance of using social care networks to reach vulnerable sections of the population. − Climate News Network

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Climate change offers rare respite for African farmers

Climate change offers rare respite for African farmers

A surprise effect of greenhouse gases is that changes in air temperature and wind patterns are increasing rainfall and crop yields in the drought-prone Sahel region.

LONDON, 18 June, 2015 − A wide belt of tropical Africa is enjoying higher rainfall than for decades past, boosting harvests and keeping the threat of drought at bay. And the main factor, according to new research, is climate change.

Drought killed at least 100,000 people in the Sahel region south of the Sahara desert over a period of about 15 years from the late 1960s, but scientists in the UK report that summer rainfall was 0.3 mm (0.01 inches) a day higher from 1996-2011 than from 1964 to 1993.

“Amounts of rainfall have recovered substantially, and it was a surprise that the increase in greenhouse gases appears to have been the dominant factor,” Professor Rowan Sutton, director of climate research at the University of Reading’s National Centre for Atmospheric Science, UK, told Reuters news agency.

The scientists report in Nature Climate Change that greenhouse gas (GHG) emissions accounted for three-quarters of the recovery in rainfall, rather than other possible factors such as changes in sea temperature or air pollution from acid rain. Air warmed by GHGs can hold more moisture − which releases more rain − and can also affect wind patterns.

Welcome sign

Not surprisingly, the report comes with qualifications, and no one is hailing it as anything more than a welcome sign that one part of Africa is gaining more than it is losing from global warming − for the moment, at least.

Prof Sutton, co-author of the study, stressed that the change in Sahelian rainfall was only local, and that warming is still affecting many parts of Africa through desertification, floods and rising sea levels.

“It would be naïve to conclude that this is a good thing for Africa,” he said. “And, in future, there are other effects. The rise in temperatures can be detrimental to crops.”

But whatever climate change may bring, the people of the Sahel are working for a better future.

The World Resources Institute (WRI), based in Washington DC, has researched the role that the region’s farmers are playing, and has produced a report containing practical guidance and examples of how to scale up “regreening”.

This is a restoration technique that hundreds of thousands of farmers in three Sahelian countries − Burkina Faso, Ethiopia and Niger − and in Malawi are already using to make their land more productive.

“It would be naïve to conclude that this is a good thing for Africa. In future . . . the rise in temperatures can be detrimental to crops”

Regreening uses a range of agroforestry and sustainable land management practices, and the WRI report focuses on one in particular that it says is “particularly promising”: farmer-managed natural regeneration (FMNR).

In FMNR systems, farmers protect and manage the growth of trees and shrubs that regenerate naturally in their fields from root stock or from seeds dispersed through animal manure. It can be an easy, low-cost way for farmers to increase the number of trees in the fields – and it is producing results in the Sahel.

In Burkina Faso, farmers are using water-harvesting techniques such as building stone lines and improved planting pits, known locally as zai. These help trap rainfall on crop fields, increasing average cereal yields from 400kg to around 900kg (880-1,984 lbs) per hectare.

Important food crops

One farmer in Burkina Faso said he had not needed to plant a single tree since 1979, because they grew naturally. Others said that FMNR had improved their yield from important food crops, such as millet.

In neighbouring Niger, the increased density of trees on cropland has reduced the time women spend collecting firewood from 2.5 hours each day to an average of half an hour.

Robert Winterbottom, a senior fellow with WRI’s forests programme, made a radical suggestion in a recent blog. He said that regreening the Sahel could enable people to stay at home, instead of joining the current tide of migration by refugees risking their lives to cross the Sahara and the Mediterranean to escape to Europe.

“Farmers have already demonstrated their ability to innovate and adopt practices that restore degraded land and provide a means to secure their futures,” he said.

“Perhaps citizens throughout Africa can prosper in their home countries, eliminating the need to take to the sea to pursue a better quality of life.” − Climate News Network

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Invader plant spreads breathing problems as world warms

Invader plant brings breathing problems as world warms

Europeans affected by asthma and other breathing problems face pollen counts four times higher than today’s by mid-century, because of an invasive plant.

LONDON, 14 June, 2015 − Alien migrants, driven by climate change and taking advantage of local benefits, have started to settle in Europe, and they are not likely to be popular. Ambrosia artemisiifolia, a ragweed from North America, produces potent allergens likely to trigger a number of unwelcome symptoms, and pollen counts are expected to quadruple by 2050.

This is not good news for those people vulnerable to rhinitis, conjunctivitis, tracheitis and asthma. Ragweed has already taken root in Burgundy, Auvergne and the Rhone-Alpes region of France, and it tends to produce its peak pollen in August and September.

Lynda Hamaoui-Laguel of the Laboratory for the Sciences of Climate and the Environment in Gif-sur-Yvette in France and colleagues report in Nature Climate Change that they thought about seed production, pollen production and the wind that drives the dispersal of pollen, and then used computer simulations to model concentrations by 2050, under a range of possible climate change scenarios.

There are all kinds of uncertainties in such calculations, but they found that, at the very least, airborne pollen concentrations would be twice as high; at the extreme outside, they could grow twelvefold. But the likelihood was that 35 years onward, the pollen counts would have quadrupled.

The spread of the invader − along with the prevalence of late summer sneezing, watery eyes and breathing problems − would increase in north-central Europe, northern France and the southern United Kingdom, where, for the time being, the pollen counts of ragweed are barely detectable.

More pollen

The researchers reckon that about a third of the spread of the plant will be due to seed dispersal: that is, the invader would be on the march even without climate change. Humans would accidentally transport the seeds along road and rail routes, and weeds would spring up along agricultural land.

The invader arrived from North America some time in the 19th century (it also made it to Australia, South America and East Asia) but in Europe it is concentrated mostly between the latitudes of 42° and 47° North, in northern Italy, south-eastern France and the Pannonian plain embraced by the Carpathian mountains in east-central Europe.

Two-thirds of its future spread, however, will happen because of changes in land use and because of climate change. That is, northern Europe will become more welcoming, and greater concentrations of carbon dioxide in the atmosphere – itself a consequence of the burning of fossil fuels – will make the plant more productive of pollen. The scientists warn, too, that the ragweed pollen itself might become more potent as a promoter of allergies.

“Once established, ragweed is difficult to eradicate because of its long-lived seed, its capacity to re-sprout after cutting and its propensity to evolve resistance to herbicides,” they warn.

“Our results indicate that controlling the current European ragweed invasion will become more difficult as the environment will be more favourable for ragweed growth and spread, highlighting the need for the development of effective and regionally co-ordinated eradication programmes.” − Climate News Network

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World leaders urged to kick killer coal habit

World leaders urged to kick killer coal habit

Oxfam report says coal-fired power plants in the G7 group of countries should all be phased out to save lives, money and the planet.

LONDON, 6 June, 2015 – Leaders of G7 countries at this weekend’s summit in Germany are being called on today to show leadership by pledging to end all coal burning for electricity generation in the industrialised world.

“Let Them Eat Coal”, a report by  the international relief charity Oxfam, explains how it can be achieved without financial difficulty, and warns that continuing to burn coal will kill millions because of the food shortages that climate change will cause.

The report is endorsed by a group of scientists, politicians, industrialists, trade unionists and campaigners, who say that only with political leadership from G7 can the prospects of dangerous climate change be averted.

Weapon of destruction

It points out: “Each coal power station can be seen as a weapon of climate destruction – fuelling ruinous weather patterns, devastating harvests, driving food price rises and ultimately leaving more people facing hunger. With these climate impacts falling disproportionately on the most vulnerable and least food-secure people, the burning of coal is further exacerbating inequality.”

It points out that G7 coal plants emit twice as much fossil fuel carbon dioxide emissions as the whole of Africa, and that “rich industrialised countries must stop hiding behind countries like China and take the lead in kicking their own coal habit”.

Coal provides 41% of the world’s electrical power but 72% of power-sector emissions. The report details how it is now cheaper to invest in and produce electricity with renewables than in coal plants in G7 countries.

The report details how many ageing coal plants each G7 country still operates, and how the wealthiest countries of the world can switch to alternatives, while creating jobs and without losing money.

“This is not a pipe dream – it is a clear
political opportunity that G7 governments
can and must seize”

Few of the G7 countries have built new coal plants, so closing them down would not lose capital investment. Ironically, Germany, which sees itself as a world leader in renewables and is the G7 host, has opened massive new coal-burning plants and will take longest to phase out coal unless it is prepared to lose money.

The report concludes that, without financial loss, France could phase out coal by 2020, the UK by 2023, and Italy by the mid-2020s. Canada and the US could follow by 2030, Japan by 2035, and Germany by 2040.

Apart from Germany and Japan, which have invested heavily in new coal plants, all G7 countries have an ageing fleet in which the original investment has long been repaid. For example, the average age of coal plants in the US is 45, and in the UK it is 41. Even in Germany and Japan, most coal plants are of the same vintage.

The report warns: “Coal power plants are the biggest obstacle standing between us and the internationally-agreed target to limit warming to 2 degrees [Centigrade].

Clean technologies

“G7 leaders meeting in 2015 can signal the beginning of the end of the coal era. By doing so, they can establish new momentum towards this year’s crucial UN climate talks in Paris and create thousands of new jobs in the clean technologies of the future.

“As the country-specific coal exit plans outlined in this paper make clear, this is not a pipe dream – it is a clear political opportunity that G7 governments can and must seize.”

Among those endorsing the report is Professor Olivier De Schutter, co-chair of the International Panel of Experts on Sustainable Food Systems. He said coal-fired stations “increasingly look like weapons of destruction aimed at those who suffer the impacts of changing rainfall patterns as well as of extreme weather events. Getting rid of our addiction to coal is both possible and necessary.”

Dr Michael Grubb, senior research fellow at the Cambridge University Centre for Climate Change Mitigation Research, said: “The extraordinary irony is that study after study is showing that coal is bad for G7 economies. The damages associated with extracting and burning coal outweigh any apparent economic value – before even considering its impact on climate change.” – Climate News Network

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Glacier loss raises high concern over water supplies

Glacier loss raises high concern over water supplies

Massively increased ice melt in the high Himalayas because of climate change could seriously jeopardise the flow of water for billions of people in Asia.

LONDON, 2 June, 2015 − The glaciers of the Everest region of the Himalayan massif – home to the highest peak of all – could lose between 70% and 99% of their volume as a result of global warming.

Asia’s mountain ranges contain the greatest thickness of ice beyond the polar regions. But new research predicts that, by 2100, the world’s highest waters – on which billions of people depend for their water supply – could be at their lowest ebb because of the ice loss.

Many of the continent’s great rivers begin up in the snows, fed by melting ice in high-peak regions such as the Hindu Kush, the Pamir and the Himalayas.

Joseph Shea, a glacial hydrologist at the International Centre for Integrated Mountain Development in Kathmandu, Nepal, and French and Dutch colleagues report in The Cryosphere journal that they used more than 50 years of climate data and sophisticated computer models of predicted climate change to study the pattern of snowpack and seasonal melt in the Everest region.

Temperature increase

They found a decrease of 20% since 1961, and signs that most, if not quite all, of the stored ice could disappear in the next 85 years.

“The signal of future glacier change in the region is clear: continued and possibly accelerated mass loss from glaciers is likely, given the projected increase in temperatures,” Dr Shea says.

”Our results indicate that these glaciers may be highly sensitive to changes in temperature, and that increases in precipitation are not enough to offset the increased melt.”

That mountain glaciers in the temperate zones and the tropics are in retreat is not in doubt. In the last two years, researchers have established patterns of ice loss in Nepal, in the tropical Andes of South America, and in the Canadian highlands.

“The signal for future glacier change in the region is clear and compelling”

Other teams have stepped back to look at the big picture, and one calculation is that around 160,000 glaciers in Europe, Asia, and the Americas are shedding 260 billion tonnes of ice each year. This is roughly as much as is now being lost from the Greenland and Antarctic ice sheets.

The consequences for sea level rise are obvious, and ominous. But glaciers have local importance too: their spring and summer meltwater drives hydroelectric power, nourishes industrial growth in the cities, and irrigates the rice and wheat crops on which billions of people depend.

The rate and extent of glacial retreat, the scientists say, depends on the levels of greenhouse gases emitted from the burning of fossil fuels in future. And some of the loss depends on the changes in the altitude at which water freezes.

Freezing levels

Right now, in the Everest region, ice forms at 3,200 metres in January, but at 5,500 metres in August. But according to Walter Immerzeel, assistant professor of physical geography at the University of Utrecht in the Netherlands, these freezing levels could rise by between 800 and 1,200 metres by 2100.

“Such an increase would not only reduce snow accumulation over the glaciers, but would also expose 90% of the current glacier area to melt in the warmer months,” he says.

Research at high altitudes is difficult, dangerous, and subject to error. The scientists focused their study on four large glaciers in Nepal’s Dudh Kosi river basin, which holds 400 square kilometres of glacial ice. They then tested eight future climate scenarios to construct the pattern of the future.

In 2007, the Intergovernmental Panel on Climate Change reported that the Himalayan glaciers could vanish as early as 2035 − but three years later had to apologise for what was described as an “unfounded” claim.

The Cryosphere authors say their own results should also be treated cautiously. But, their paper concludes, “the signal for future glacier change in the region is clear and compelling”. – Climate News Network

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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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Rainforests are left on edge of destruction

Rainforests are left 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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