India’s coastal villages map out disasters strategy

India’s coastal villages map out disasters strategy

The Indian Ocean can be an angry and sometimes lethal neighbour, but those who live beside it are now learning how to prepare for its next onslaught.

CHENNAI, 26 May, 2015 – It has been over a decade since the devastating tsunami struck southeast Asia, but the horrific memories remain as vivid as ever for people in the coastal villages of the south Indian state of Tamil Nadu.

Now, in the aftermath of the 2004 tsunami and also two cyclones, local people are benefiting from the Indian government’s encouragement of international co-operation in helping vulnerable communities, and have produced a hazard map as a precaution against future disasters.

Vikas Shankar, from the fishing village of Sulerikattukuppam, remembers clearly the moment the tsunami struck.“I was engrossed in playing cricket when I saw water entering the village,” he says. “I thought it was just another day when the sea poured in. Then, suddenly, I saw my mother caught in a whirlpool and realised something was seriously wrong.”

His mother, Tilakavathy, survived the tsunami’s fury, but recalls: “I thought this was really the end of the world.”

Completely destroyed

Amazingly, no one in the village died, but fishermen lost their gear and livelihoods, and many buildings close to the shore were completely destroyed.

The tsunami prompted Tilakavathy and her husband to decide not to send their sons to sea to earn a livelihood.

When Vikas, their youngest son, was old enough, he was sent instead to the local community college, built in 2011 by the state government to provide education and alternative livelihood opportunities for the fishing community.

The local people, recognising the need for disaster preparedness, are now involved in a programme that focuses on  developing communication tools for vulnerable communities and raising awareness of other disaster-related issues.

Krishnamurthy Ramasamy, professor of applied geology at the University of Madras, was formerly the principal of the community college. He says: “We realised the need for international collaboration to build a curriculum on disaster management and field-based learning activities.”

Kyoto University in Japan was one of the universities keen to work with him, and two Australian universities, Melbourne and Victoria, also joined in, helping with funds, curriculum development and exchange visits.

“We were taught how and why cyclones and tsunamis happen. It helped us to understand disasters in the first place.”

The college itself fostered community-based preparedness by offering disaster management as an optional subject, and by helping to set up a Local Residents’ Alliance (LRA) in 2013 to mobilise villagers. Most members of this group were parents of students from the college.

Vikas Shankar says: “In the class, we were taught how and why cyclones and tsunamis happen. It helped us to understand disasters in the first place.”

To learn about other people’s best practices, Professor Ramasamy visited communities along the Japanese coast, and there he made a significant discovery. He says: “The first thing I noticed in each village was the hazard map. I thought that we needed this too.”

Back at the college, work on hazard map preparation began, and the first step was students surveying their own villages to understand the geography better.

Teams went from house to house and marked all the huts in the village. They counted the number of people in the house, with details of numbers of women, children, old and disabled people living there. All this information went on the hazard map.

Miwa Abe, from the Centre for Policy Studies at Kumamoto University, Japan, who trained the Indian students, says: “A hazard mapping exercise with local people gives them an opportunity to know their village.

“It is not only about environmental conditions, but also human relationships, social networks, architectural conditions. Usually people do not think about their own area because it is too familiar to them.”

Evacuation routes

The teams also prepared evacuation routes, and, after six months of rigorous work, the students presented the final map to the local people.

Today, as one walks into the village, the first thing to catch the eye is the big blue hazard map board at its entrance. It shows the evacuation routes to be followed during disasters, and also the village’s population distribution − crucial information so that local people will know who to rescue first, and where they live.

The village’s approach is now being used as a case study in efforts to prepare community-based disaster management (CBDM) plans for the entire district, and eventually as a model for the state. The Tamil Nadu government has given land adjacent to the college to establish permanent infrastructure and to provide better facilities for the students.

Rajalakshmi Mahadevan, a fisherman’s daughter, says: “The evacuation map can be read by anyone, even a newcomer. Now we know which house to go to, who to evacuate first, and this has lifted the fear of disaster from local people’s minds.”– Climate News Network

  • Sharada Balasubramanian, an independent journalist from Tamil Nadu, India, writes on energy, agriculture and the environment. Email: sharadawrites@gmail.com; Twitter: @sharadawrites

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Rising temperatures mean fewer but fiercer hurricanes

Rising temperatures mean fewer but fiercer hurricanes

Climate change brings mixed prospects for people threatened by hurricanes: they are likely to occur less often, but when they do they will be even more destructive.

LONDON, 25 May, 2015 − Once again, scientists have confirmed the link between climate change and destructive hurricanes. The link is a simple one: a warmer world could mean fewer tropical storms, but those that arrive are likely to be more violent.

The conclusion is not new: other teams have already proposed that global warming linked to increases of carbon dioxide in the atmosphere as a consequence of fossil fuel combustion could drive tropical cyclones to higher latitudes and that the most destructive hurricanes could happen increasingly often. A British team has even linked better air quality – fewer sulphate aerosols and dust – to a greater probability of more violent winds.

But Nam-Young Kang, who now directs South Korea’s National Typhoon Center, and James Eisner, a geographer at Florida State University, set about a study of weather data and hurricane, cyclone and typhoon records between 1984 and 2012 to see if they could identify a pattern of change.

In the last 60 years or so, global average temperatures have risen, but are still less than 1°C above the average for the centuries before the Industrial Revolution. Hurricanes are linked to sea surface temperatures and the hurricane “season” does not start until ocean surface levels go beyond 26°C.

“We’re seeing fewer hurricanes, but the ones we do see are more intense. When one comes, all hell breaks loose”

The two scientists reckoned that even slightly higher average temperatures would mean more energy and therefore higher wind speeds at sea as well. They report in Nature Climate Change that they found what they were looking for: a pattern. On average, storm wind speeds had increased by 1.3 metres a second and there were 6.1 fewer tropical storms a year worldwide than there would have been if land and water temperatures had remained constant.

The research paper describes tropical cyclones – a term that for geographers also embraces Pacific typhoons and Atlantic hurricanes – as “perhaps the least welcomed natural phenomena on our planet” and points out that even well-developed, highly complex societies are exposed to them, and vulnerable. Superstorm Sandy, which began as an Atlantic hurricane, hit New York in 2012 with devastating consequences and even set the nation’s earthquake alarms ringing.

Professor Eisner has already established a link between temperatures and tornado hazard.  The new study delivers a statistical warning of a trade-off between frequency and strength offshore as well.“We’re seeing fewer hurricanes, but the ones we do see are more intense. When one comes, all hell breaks loose,” he said. − 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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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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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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Australia pays cost of climate-driven heat waves

Australia pays cost of climate-driven heat waves

Australian researchers measure cost of drop in workers’ performance as global warming drives temperatures to record levels.

LONDON, 9 May, 2015 – Climate change can be bad for a country’s economic health. Absenteeism and lower productivity because of heat stress may have cost the Australian economy an estimated US$6.2 billion in the year 2013/14, according to new research in Nature Climate Change.

The summer of 2013 brought the hottest year ever recorded to Australia, a year marked by record temperatures linked to human-made climate change as a consequence of the burning of fossil fuels.

Studies of physiological response to unusual heat predict that economic productivity could be affected. But Kerstin Zander of Charles Darwin University in Darwin in the Northern Territories and colleagues decided to find out directly by asking people what happened to them as the temperatures soared to dangerous levels, and stayed there.

In 2014, they asked 1,726 employed Australians – office workers, labourers, managers, technicians, sales people and professionals – to recall the days that they missed work because of the heat, and the days on which they went to work but didn’t achieve very much because of the heat, and then calculated an economic loss linked to each answer.

More accidents

The average across all questioned employees came to US$655 for the year. Then they scaled this total across the entire workforce to arrive at an annual national cost of $6.2bn.

Unusually hot weather might be welcome during beach holidays but – the risks of potentially lethal heat stroke and heat exhaustion aside – it is also linked to higher work accident rates because of lapses of concentration, higher levels of fatigue and poor decision-making, and higher stress hormone levels.

The employees who went to work in the heat did their best – three quarters of them said they put in longer hours to make up for the lost output – but they also calculated that they achieved 35% less under such conditions.

Australia’s $6.2bn loss represents less than half of one percent of Australia’s gross domestic product (GDP), and if the heat extremes of 2013 were a once-in-a-century event, this figure would be insignificant. But all the climate forecasts promise more such heat waves to come for the world’s largest island.

“Adaptation to reduce heat effects should be adopted widely if severe economic impacts from labour productivity are to be avoided”

Global warming may have increased fivefold the probability of more record-breaking summers, according to one set of studies, and 2014 was marked by more of the same. Other research groups have linked Australia’s drought and fire risk to anthropogenic emissions of fossil fuels but, paradoxically, the levels of greenhouse gas emissions in Australia itself are on the increase.

The authors note that productivity models based on human physiology and climate projections suggest that by 2080, some places – parts of Asia and the Caribbean, for instance – could be subjected to heat extremes that will make work difficult or intolerable. The forecasts say productivity could fall during the hot months in such places by 20% by 2050, and by up to 27% by 2080. In that context, Australia in 2013 had a taste of things to come.

“Although this was a period when many Australians experienced what is at present considered exceptional heat,” the authors say, “our results suggested that adaptation to reduce heat effects should be adopted widely if severe economic impacts from labour productivity are to be avoided, if heat waves become as frequent as predicted.” – Climate News Network

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Tree-based farming could deliver abundant benefits

Tree-based farming could deliver abundant benefits

In addition to mitigating the effects of climate change, forests can help alleviate hunger and provide a safety net for some of the world’s poorest people.

LONDON, 8 May, 2015 – Forests may be the green investment with the richest returns for humankind, according to new research.

While one study outlines the ways in which forests provide food, fuel, shelter and a safety net for more than a billion humans, a separate one confirms that a canopy of older, sturdier trees helps protect the saplings and juvenile growths against heat and drought.

An international team of more than 60 scientists collaborated on a report − Forests, Trees and Landscapes for Food Security and Nutrition: a Global Assessment Report − just published by the International Union of Forest Research Organisations (IUFRO).

“Large-scale crop production is highly vulnerable to extreme weather events, which may occur far more frequently under climate change,” says Christoph Wilburger, who co-ordinated the IUFRO initiative. “Science shows that tree-based farming can adapt far better to such calamities.

Key role

“We know that forests already play a key role in mitigating the effects of climate change. This report makes it very clear that they also play a key role in alleviating hunger and in improving nutrition.”

Climate scientists tend to consider forests as “carbon sinks” − agencies that soak up carbon dioxide from the atmosphere and that could help counter the rising levels of the greenhouse gas released by the burning of fossil fuels.

But forests also have a role in water storage and in protecting land from the forces of erosion.

Forest fruits and nuts are an important nutrition source for many. The iron content of the dried seeds of the African locust bean and raw cashew nut can, for instance, match the flesh of chickens. And forests are shelter for sources of wild meat, fish and edible insects.

“Extensive losses of forest canopy . . . will amplify the effects of climate change”

In developing countries, around 2.4 billion households use wood and charcoal for cooking and heating, and forests deliver a multitude of what are sometimes called ecosystem services − such as supporting bees and other crop pollinators, delivering fodder for village livestock, and protecting streams and watersheds.

Worldwide, the lower the levels of prosperity, the higher the dependence on forests. In the Sahel region of Africa south of the Sahara, trees contribute on average four-fifths of household income − mostly through shea nut production.

The report also points out that the expansion of agricultural land accounts for 73% of forest loss worldwide.

Increasing threat

But if forests keep people safe, what keeps a forest in leaf when drought, extremes of heat and the attrition of climate change are also an increasing threat?

Solomon Dobrowski, of the Forest Landscape Ecology Lab at the University of Montana, and colleagues report in Global Ecology and Biogeography that the regeneration of future forests could depend on shelter from the extensive canopy provided by the adult trees in mature woodland.

Juvenile trees are more shallow-rooted and more vulnerable to high winds, intense sunlight, high temperatures and extended drought. Without a shady, protective canopy, they could suffer. And without juvenile trees, a forest could only decline.

Professor Dobrowski warns: “Extensive losses of forest canopy from disturbances such as severe wildfire will amplify the effects of climate change.” – Climate News Network

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US braces itself for even worse wildfire season

US braces itself for even worse wildfire season

Years of drought and higher temperatures mean the chance of devastating wildfires in the southwest US is higher than ever − particularly in southern California.

LONDON, 3 May, 2015 – The firefighters are primed, hoses at the ready. May and June are often the peak months for forest fires in the southwest of the US, and the outlook for this year is grim.

“I wish I could have some hope,” says Dr Wally Covington, director of the Ecological Restoration Institute at North Arizona University. “It’s just a terrible situation in southern California.”

Covington, an internationally recognised expert on forest restoration, says a prolonged drought, higher temperatures and stronger than usual winds mean big wildfires are inevitable across the southwestern US.

The main season for wildfires in the region has in the past been from mid-May through till late September, but now forest fires burn virtually year round.

Vulnerable landscape

“Climate change and misguided forestry policies have combined to present a landscape very vulnerable to devastating fires,” Covington told the Climate News Network.

“Since around 2000, we’ve seen more severe dry weather, matched with high winds throughout the western US. Intense firestorms are the result. Get in the vicinity of one of those and it’s like being near a blast furnace.”

Covington and other experts say it is vital that people and government policy adapt to the changes in climate.

Over the years, forests have been densely planted in many areas, and old forestry practices – such as clearing out forest and shrubland by regularly burning off old tree cover and dry shrubs – were stopped.

“We’ve just got to stop building in those places.
It was crazy 40 years ago – and it’s
even more crazy now”

The result is not only an abundance of dense forested areas where fire can build up and spread easily, but also accumulations of dried-out grasses and shrubs − referred to as fine fuel.

Opening up forest areas and reintroducing controlled, periodic burning to rid the landscape of these tinder-dry fuels is key, according to Covington.

He says: “The US Forest Service now sees opening up forest areas and restoring them to what they once were – right across the US – as its primary goal. That’s a huge policy breakthrough.”

The past three years have been among the driest on record in California, and there are fears that the drought will continue.

Historic low

Wells have dried up in many areas, reservoirs in the state are at a record low, and the snowpack in the Sierra Nevada mountain range – vital for feeding water on to the lands below – is at an historic low for the time of year.

For the first time in California’s history, mandatory water restrictions have been brought in, with cities and towns required to cut water use by 25%.

This does not, however, apply to the state’s multi-billion dollar agricultural industry, which uses up to 80% of water supplies.

Besides the drought, strong winds and higher temperatures, other factors have increased the risk of wildfires across the region. For example, building houses in forest and shrubland areas has also increased the danger of fires being ignited.

“We’ve just got to stop building in those places,” Covington says. “It was crazy 40 years ago – and it’s even more crazy now.” – Climate News Network

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Man-made climate change increases extinction dangers

Man-made climate change increases extinction dangers

New research warns that the survival of a sizeable proportion of life on Earth is being put at risk as fossil fuel emissions push up global temperatures.

LONDON, 2 May, 2015 – Climate change threatens one in six of the world’s species with extinction, according to new research.

The higher the average rise in planetary temperatures because of man-made global warming, the faster the rate of biodiversity loss − and the greater the survival dangers for a significant proportion of life on Earth.

Two studies published on the same day in the same journal reach the same conclusion: that climate change from any cause is bad for an ecosystem’s health and presents dangers of species extinction.

That the natural world is responding uneasily to man-made, or anthropogenic, climate change is not in doubt. In the last two years, scientists have shown that it can be the last straw for a population already under pressure, or so vulnerable it can no longer survive without human help.

Change habitat

It can change the habitat and climate in which plants and animals have evolved, but offer no safe place to which to migrate, and it can provide the conditions for new threats to flourish.

Genomic evidence shows that, in the recent past, it can constrict the numbers available for breeding, and ancient palaeontological evidence has linked greenhouse gas concentrations to catastrophic mass extinction.

Mark Urban, professor of ecology and evolutionary biology at the University of Connecticut, US, now reports in the journal Science that a comprehensive look at the whole picture tells the same story.

His warning is that if fossil fuel emissions continue on the business-as-usual scenario, and temperatures on average reach the predicted 4.3°C increase, then one in six of the world’s species could face extinction.

“We believe the past can inform the way we plan our conservation efforts”

There are problems with this kind of research: more than a million species have been described and named, but nobody knows, to an order of magnitude, how many species there might actually be on the planet. The living world is still largely unknown.

So Dr Urban surveyed 131 published predictions of extinction, and then subjected them to a mathematical technique called meta-analysis.

Extinction risks were higher in South America, Australia and New Zealand − all places that harboured diverse assemblies of endemic species with small ranges and,  in the case of the large islands, not a lot of choice about places to which to migrate.

“Extinction risks from climate change are expected not only to increase but to accelerate for every degree rise in global temperatures,” he concludes. “The signal of climate change-induced extinctions will become increasingly apparent if we do not act now to limit future climate change.”

Seth Finnegan, a biologist at the University of California Berkeley, and colleagues report in Science that they looked at the marine fossil record during the climate ups and downs of the last 23 million years.

They identified 2,897 different fossil genera from six major groups – marine mammals such as seals and whales, sharks, bivalves, gastropods or snails, echinoids and corals – and used the evidence to arrive at a baseline for a “natural” extinction risk that could not be blamed on humans.

Vulnerable species

“Our goal was to diagnose which species are vulnerable in the modern world, using the past as a guide,” Dr Finnegan says.

“We believe the past can inform the way we plan our conservation efforts. However, there is a lot more work that needs to be done to understand the causes underlying these patterns and their policy implications.”

Not surprisingly, those vertebrates with small geographic ranges were at the highest risk − with whales, dolphins and seals more likely to face extinction than invertebrates such as sharks and corals.

The tropical waters of the west Atlantic and the west Pacific provided the most vulnerable ecosystems in the last 23 million years, and these regions today are predicted to experience the fastest rates of climate change and the greatest human impact in the shape of habitat destruction, overfishing and pollution.

The researchers also established another measure of extinction risk: in terms of species survival, it is 10 times more perilous to be a mammal than a clam. – Climate News Network

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History lessons highlight climate threat to birds

History lessons highlight climate threat to birds

Evidence from the Ice Ages helps show how vulnerable bird populations are to change driven by human-induced global warming.

LONDON, 25 April, 2015 − Climate change can seriously alter the numbers and the prospects for survival of the planet’s living things, according to researchers in Sweden and China.

The scientists’ findings are the result of taking a long, cool look at the big picture – rather than the still-sketchy evidence from climate change now – of what happened to bird populations during the Ice Ages.

Krystyna Nadachowska-Brzyska and Hans Ellegren, of the Evolutionary Biology Centre at Uppsala University, and collaborators at the Beijing Institute of Genomics used a sophisticated new technique to calculate the rise and fall of population sizes of 38 species of bird during the last several million years − a period punctuated by the advance of vast sheets of ice and shorter warm interglacial periods.

Natural change

The results answer questions about how species fared during periods of natural change, in an era when human numbers were tiny and human technology insignificant.

But they also highlight the vulnerability of already-endangered bird populations during a period of change driven by global warming as a consequence of greenhouse gas emissions into the planet’s atmosphere from the widespread use of fossil fuels.

The researchers exploited techniques made possible only in the last decade or so to recreate the past.

They compared genomic mutations among unrelated individuals in each species, and employed a new mathematical technique that goes by the name of “pairwise sequentially Markovian coalescent”, or PSMC, to tease out the history encoded in those comparisons.

“Climate events significantly affect the effective breeding sizes of bird populations”

The reasoning goes like this: mutations in DNA occur at a more or less predictable rate through the generations of a species, so DNA can be considered both as an indicator of relationships and as a kind of clock.

Using such a clock, based on DNA inherited only through the maternal line, scientists long ago calculated a potential date for the origins of Homo sapiens.

In 2011, a team of scientists reasoned that the same clock, subjected to some mathematical interrogation, might answer questions about how many individuals might have existed in a population at a particular time.

Their first result was to confirm from the variation – or lack of variation – in the genome samples that some distant catastrophe caused a sharp drop in human population numbers 60,000 years ago or more, after which human numbers expanded again.

Now the same techniques have been applied to genomic evidence from barn owls, budgerigars, bald eagles, Dalmatian pelicans, domestic pigeons and Pekin ducks, as well as less familiar creatures such as the rhinoceros hornbill of south-east Asia, and the kea, a ground-dwelling alpine parrot from the South Island of New Zealand.

“The majority of all species exhibit cyclical swings in numbers, and these swings often coincide with the periods of ice ages,” Dr Ellegren says. “The last ice age (110,000-12,000 years ago) had a particularly heavy impact on birds. Many species suffered their most dramatic falls in numbers then.”

What the scientists were looking for was something called “historically effective population size” in their choice of species − broadly, the number of survivors that could interbreed and rear the next generation.

In the case of, for example, the downy woodpecker of North America, this number was at a low point of 150,000 two million years ago, then rose to 1.2 million before falling, around 100,000 years ago, to about 200,000.

Severe declines

They found severe declines in 22 of the 38 species over a period that coincided with the last ice age. Two species of eagle and the common ostrich saw their numbers reduced from tens of thousands to mere thousands. But even much more numerous species, such as pigeon and budgerigar, experienced significant change.

Scientists have already begun to measure change in the natural world in response to average temperature rises by shifts either in timing or latitude, or even altitude.

The Uppsala research offers a kind of baseline of historical change, and could help conservation bodies now concerned with saving species already considered at risk of extinction because of habitat destruction, hunting and human-induced climate change.

“The results from our study document that such climate events significantly affect the effective breeding sizes of bird populations,” the authors conclude. – Climate News Network

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