The cost of managing paths is expected to rise according to the report

Climate change threatens to put "chronic pressure" on the state of public paths in upland and lowland Scotland, according to a new report.

The study investigated the potential effects of warmer, wetter conditions on the design and management of tracks.

Researchers looked at paths in Aberdeenshire, Dumfries and Galloway, Loch Lomond, Lothian and Wester Ross.

Erosion and extra spending on drainage have been highlighted in the Scottish Natural Heritage-commissioned report.

The report said temperatures were expected to rise, which would affected the process of ground freezing and thawing, and there would be more "frequent and intense" extreme rainfall events.

The report said action could be taken to prepare for the effects of climate change.

These included agencies sharing knowledge on how to best drain and repair paths and, also, constructing routes "more resilient" to extreme weather.

The report's authors looked at paths around Kinlochewe, in Wester Ross, Loch Lomond, Glentrool, in Dumfries and Galloway, Aboyne, in Aberdeenshire, and Dunbar, in East Lothian.

Wind turbines at West Somerton, Norfolk. The OECD reports a surge in patents for clean-energy technologies. Photograph: Graham Turner for the Guardian

Green bonds could raise hundreds of billions of dollars a year to spur a shift to cleaner economic growth, if governments set strong environmental goals, the OECD said on Wednesday.

In a review of efforts promoting sustainable growth, the Organisation for Economic Co-operation and Development urged more innovation to favour investment in clean energy such as wind and solar power, and a drive to place more value on many issues, from public health to clean water.

"There is scope for scaled-up issuances of green bonds [in the hundreds of billions per year]," the OECD said.

The 34-nation group said the market size of all green bond issuances to date was about $11bn (£6.7bn), "a drop in the ocean" equating to about 0.012% of the capital held in global bond markets estimated at $91 trillion.

But a condition for a more liquid market for green bonds was "transparent policies based on long-term, comprehensive and ambitious political commitments", it said.

Last year, governments agreed, at UN talks in Mexico, to the goal of limiting the rise in global average temperatures to below 2C degrees above the temperatures of pre-industrial times. The aim would be to try to avoid more devastating droughts, floods, heatwaves and rising sea levels.

But the UN says promised cuts in greenhouse gas emissions, stoking global warming, are too small to keep below the 2C degree ceiling.

The OECD report said there were some signs of progress towards a greening of the world economy, such as the surge in patents for clean-energy technologies. "Green technology development is accelerating in some areas," it said.

The report pointed to a 24% rise in the number of patented inventions for renewable energies from 1999-2008, as well the 20% gain in patents for electric and hybrid vehicles, and 11% rise for energy efficiency in buildings and lighting. That compared with a 6% overall increase in patents in the period, it said.

Japan, the US and Germany were leading patent applications in clean technologies.

"Innovation will play a key role," the report said of the need for a shift to greener growth in coming years.

The report added said the world needed to widen economics beyond the conventional yardstick of GDP to include non-market values such as clean air and water, health and education, and diversity of animal and plant life.

The costs of fighting climate change could be halved on average if the world placed a monetary value on longer human life-spans arising from a move away from high-polluting fossil fuels.

The US would benefit most, according to the estimates. Gains in life expectancy through reduced air and water pollution "would overcome the monetary cost of climate change mitigation by a significant amount".

The OECD said of the shift to green growth: "The scale of adjustment should not be overstated. Significant reductions of greenhouse gas emissions can be achieved with only limited effects on the pace of employment growth."

The organisation pointed to estimates suggesting it would cost $46tn to adapt to, and combat, climate change, up to 2050 – amounting to about $1tn a year.

Liquid camp winning out despite mixed signals.

 

 

The icy plumes on Enceladus are proposed to be driven by liquid water beneath the moon's icy surface.NASA/JPL/Space Science Institute

Evidence is growing in support of the idea that liquid water lies concealed beneath the surface of Saturn's icy moon Enceladus.

Some scientists hope that the characteristic plumes of ice crystals seen erupting from the moon's surface are geyser-like features fed by an underground water source, with all that would imply about Enceladus as a possible abode for life. Others argue that the crystals could be formed by 'dry' processes such as the breakdown of clathrates (which combine ice and trapped gases such as methane) or from the sublimation of subsurface ice layers that never pass through a liquid phase in the transition from ice to gas.

Many of the latest findings, announced yesterday at a meeting of NASA's Enceladus Focus Group at the SETI Institute in Mountain View, California, reveal signs of liquid water.

One such sign is that the plumes seem to be made up of about equal parts ice and gas, says Andrew Ingersoll, a planetary scientist at the California Institute of Technology in Pasadena.

"It's hard to get solid-to-gas ratios of more than one per cent if all the particles are forming from a vapour," he said. "I think we should be thinking about the possibility that you throw out a big, heavy blob of liquid and it reaches the vacuum of space and explodes into a cloud of smaller particles."

Chemical conundrum

Another sign that liquid water is present is the chemistry of the materials being emitted by the plumes. Frank Postberg, a physicist at Heidelberg University in Germany, has noted, for example, that ice crystals in Saturn's E ring that originated on Enceladus are rich in sodium, which wouldn't be possible if they had been emitted as a vapour that subsequently re-condensed into ice.

However, not all of the chemical evidence points to liquid water. Hunter Waite, a space scientist at the Southwest Research Institute in San Antonio, Texas, noted that the chemical composition of the plumes, as determined by the ion neutral mass spectrometer on the Cassini spacecraft, reveals some compounds whose presence isn't consistent with a liquid source. One such example is hydrogen cyanide, which, if it had ever met with liquid water, should have reacted with other compounds in it to produce other compounds that have not yet been found in plumes.

"There is no clear pattern here," said Waite. "There are some things that are consistent with solubility in water and other things that don't make sense in that regard."

One possibility, he said, is that chemicals in the plumes might come from multiple processes all happening at once.

Long-lived plumes

Whatever their cause, it seems that the plumes have been active for a long time. Ice crystals falling back to the moon's surface have piled into drifts around 125 metres thick, according to Paul Schenk, a planetary scientist at the Lunar and Planetary Institute in Houston, Texas. The falling ice accumulates at a rate of about 1 millimetre every 1,500 years, he says, so the plumes must have been around for tens of millions of years.

Schenk based this conclusion on high-resolution photos that show a region just north of the geyser zone whose topography is muted into rounded contours indicative of deep snow.

"It's different from what you see in other areas that have been photographed at high resolution. Those had incredible detail everywhere you look. This is much smoother," says Schenk.

Other scientists at the meeting received this news with excitement. "This is a whole new order of constraints for how long the plumes have been active," says Postberg. Until now, he said, all that had been known was that they had been active for long enough for escaping ice grains to form Saturn's E ring — a process that would have taken between a few hundred and one thousand years.

"That's a big step from a thousand to ten million years," he said.

Force factor

The source of the energy driving the plumes remains unknown. According to the latest estimates, the plumes and related hot spots are currently radiating 16 gigawatts of energy. But Enceladus receives only a fraction of that from the combination of radioactive decay and tidal flexing from Saturn's powerful gravity, said Francis Nimmo, a planetary scientist at the University of California, Santa Cruz.

As a result, most of the scientists at the meeting believe that, however many million years they may have been around for, the plumes don't operate continuously, instead turning on and off at intervals.

An even tougher question is whether Enceladus produces enough heat to maintain liquid water beneath its surface.

Nimmo doesn't think that there is enough heat to maintain a layer of water beneath the ice moonwide. But if all of the tidal heating were to be focused in one zone, there would be enough heat, he says, for a large regional ocean to exist indefinitely beneath the jets. And once such an ocean forms, he says, it concentrates tidal heating, and thereby becomes self-perpetuating. 

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Return of the Jedi

Photograph courtesy Piotr Naskrecki, Conservation International

Back for an encore after a round of Web stardom as "Yoda bat" last fall, Papua New Guinea's tube-nosed fruit bat has now been named one of the top 20 new or rarely seen species encountered during the first 20 years of Conservation International's Rapid Assessment Program (RAP), which launched in 1990.

(Read more about the tube-nosed fruit bat.)

The RAP expeditions typically send large teams of scientists into remote habitats for intense, monthlong surveys.

"We go out and explore so that we can bring a wide range of new species—1,300 so far—and thousands of other rare and really interesting species to the public and policy makers," explained RAP director
Leeanne Alonso.

"Showing people what's there helps us make the best decisions about how to manage areas to keep these species around, while continuing the benefits that humans get from these places."

In other words: Help us, they will.

—Brian Handwerk

Published April 18, 2011

1st Place, "Beauty of the Night Sky" Category

Photograph by Stephane Vetter, TWAN

A dazzling green aurora frames the arc of the Milky Way over Jökulsárlón, the largest glacier lake in Iceland, on March 10. The picture is a first-prize winner in the Second International Earth and Sky Photo Contest's "Beauty of the Night Sky" category.

Organized by astronomy-education projects The World at Night (TWAN) and Global Astronomy Month, the contest honors pictures that meet one of two criteria: "either to impress people on how important and amazing the starry sky is, or to impress people on how bad the problem of light pollution has become." In total, ten winners were announced May 9 in either the "Beauty of the Night Sky" or "Against the Lights" category.

To achieve the contest goals, organizers asked for "landscape astrophotography"—pictures of world landmarks against the night sky. This style "brings Earth and sky into one frame, and it's a bridge between the night sky and the ... environment," TWAN founder and contest judge Babak Tafreshi said in an email to National Geographic News.

"If we considered dark, starry skies a part of nature and our living world heritage, then we would try to preserve it like the other parts of nature."

Satellite mission to monitor ocean salinity may help solve climate questions.

 

Aquarius will measure the saltiness of the oceans.NASA

How salty are the oceans? Back in the 1970s, scientists dreamed that a satellite could provide the answer by measuring microwave emissions from the seas.

That dream is rapidly becoming a reality. NASA plans to launch a new instrument, Aquarius, on 9 June, which should allow researchers to monitor global salinity measurements to help answer some pressing climate questions. Because salinity is linked to both evaporation and water density, the new data could help scientists explore questions about precipitation trends as well as about ocean circulation and the uptake of carbon dioxide by seawater.

"It's going to be a leap forward for the science of oceanography," says NASA project scientist Eric Lindstrom. In particular, he says, Aquarius could help scientists confirm theories about how the global water cycle — experienced in everyday life as surface evaporation, rainfall and snowfall — is changing in response to global warming.

Aquarius will fly as part of a joint mission with Argentina's National Commission for Space Activities, which built the main satellite as well as other instruments on board and which will take the lead in managing the mission from the ground.

The mission comes on the heels of two disasters for NASA's Earth observations projects. In 2009, the Orbiting Carbon Observatory, which would have monitored carbon dioxide levels, failed to launch; earlier this year, the Glory probe, which would have advanced solar monitoring and global aerosol measurements, suffered the same fate (see Mourning Glory).

The heart of Aquarius is a set of three ultrasensitive radio receivers that will pick up the weak microwave radiation emitted naturally by the ocean. Those emissions vary according to the electrical conductivity of the water, which is directly tied to its salinity. In combination, the three instruments will be able to gather data across a swathe of ocean nearly 390 kilometres wide, allowing Aquarius to cover the whole globe once every seven days, measuring changes in salinity down to 2 parts per 10,000 in seawater.

Given that most of the salinity data going back 50 years comes from measurements from ships, this represents a huge advance, says Tim Boyer, an oceanographer with the National Oceanic and Atmospheric Administration in Silver Spring, Maryland. "It's definitely good enough to see large-scale seasonal cycles" such as the Amazon outflow, Boyer says, but scientists won't know exactly how much they can do until they see what the data looks like. "Until you put the satellite up, you don't know what you are going to get."

Salinity levels vary widely across the ocean. River systems dilute seawater around deltas, and evaporation can increase the salinity in one area of the ocean only to produce precipitation that reduces salinity in another. Or a strong sun, combined with hot dry air blowing from the Sahara, might increase salinity off the west coast of Africa while fuelling storms that can grow into hurricanes across the Atlantic Ocean.

In recent years, scientists have begun collecting salinity data using the Argo ocean observing network. These probes collect data in the deep ocean and periodically surface to transmit the measurements to scientists on shore. But that system only collects salinity data below a depth of about 4 metres. Scientists are now working to deploy around 100 Argo floats that produce a salinity profile all the way up to the surface.

Those sensors will help scientists to bridge the data gap between Argo and Aquarius, says Steve Riser, an oceanographer at the University of Washington in Seattle. And if it turns out that surface readings correspond well with the readings at 4 meters, Riser adds, scientists might be able to extrapolate surface salinity from the entire network of some 3,200 floats. "Based on what we know so far," Riser says, "I would suspect that most of the Argo floats will have some validity."

For Raymond Schmitt, a senior scientist at the Woods Hole Oceanographic Institution in Massachusetts, Aquarius could help resolve an apparent discrepancy between global climate models and historical observations of ocean salinity.

Global warming is expected to speed up the water cycle. Because warmer air holds more water, one would expect to see more evaporation, more precipitation and, consequently, more extreme weather. Observations over the past 50 years seem to confirm that these changes are leaving their imprint on ocean salinity: salty regions have become saltier, and less salty regions have grown even fresher.

While the salinity data would seem to suggest a massive acceleration of the water cycle, Schmitt says, climate models tend to suggest that weaker winds will offset the effects of higher temperatures, leading to a more moderate increase in the water cycle. It is also possible that global warming is driving shifts in ocean circulation that could contribute to the changes in salinity, but that is unlikely to explain the whole effect.

"We have reason to be concerned that the water cycle is changing a lot faster than predicted, and that could be serious" because this would translate into more extreme weather in the years and decades to come, says Schmitt. Answering these questions won't be easy, even with new data. "Aquarius is trying to do a hard thing," he says, "but to me, ocean salinity is the best gauge we have on what these water cycle changes are going to be." 

Many birds, mammals and amphibians vary the frequency and intensity of their vocalizations to expand their vocabulary. Aaron Rice, Bruce Land and Andrew Bass at Cornell University in Ithaca, New York, show that fish also use forms of 'acoustic nonlinearity', such as frequency jumps and biphonation — the simultaneous expression of two independent frequencies.

The authors recorded and analysed the vocal calls of three-spined toadfish (Batrachomoeus trispinosus; pictured), which produce 'hoots' and 'grunts' by vibrating their swim bladders. Around 35% of the fish's calls had at least one form of nonlinearity. Severing the animals' vocal motor nerve stopped them producing these effects.

The fact that fish make complex vocalizations previously found only in four-limbed vertebrates suggests that there is a major selection pressure to produce innovation in acoustic signals.

Just a week to go before we decamp from Springwatch Towers and make our way to our new home at Ynys-hir.

Things are hotting up in the office, and here on the web the excitement's building as more and more exquisite wildlife photography floods into the Springwatch Photo Group.

So here are our mid-May picks of your fantastic photos...

Common blue © Jason Elmore

Dotterel © David Cookson

Damselfly © Adam Tacon

Wood mouse © Andrew Everhale

Arctic terns © Keith Edmunds

Spider © Anthony Nixon

Swallow © Stressed Jim

Liquid lunch © Martin Cook

Blue tit © Grant Glendinning

Marsh fritillary © Pete Withers

19 May 2011   

The Gold of Kinabalu: orchid treasure on the edge of extinction

Ruthless hunters track their prey around the globe, snatching stunning individuals from their homes before they can even be named.

The beauties only surface in the shadiest of nurseries and high prices for their lives are agreed under the counter by hungry-eyed collectors.

This is not the plot from a harrowing tale of people smuggling but the fate of rare and highly prized orchids.

The plants have inspired frenzied collection since the 18th century with their lustrous blooms and incredible variety.

Now, scientists say the illegal collection of orchids is pushing species to the edge of extinction, with dire consequences for biodiversity.

To a dedicated collector of wild-sourced orchids, price has no bearing”

End Quote Dr Richard Thomas TRAFFIC International

With some vulnerable species available on the black market before they can even be formally named, biologists and customs officers alike are battling to preserve the captivating plants.

Sex appeal

Admired for their beauty, orchids make up the largest family of flowering plants (Orchidaceae) with over 26,000 species.

The plants vary enormously from tiny 3-4mm Bulbophyllum minutissimum to 20m long vanillas: lianas that grow high up in rainforest.

What unites them is the unique way they germinate from seeds, developing a tuberous mass of cells to form a seedling plant.

For orchid admirers however it is the sensual differences between the plants that inspire such admiration and many are driven wild by the unique shape, scent and sight of new species.

Victorian Britons referred to the condition as "orchidelerium", an insatiable lust for collecting the plants.

From delicate ghost orchids to the beautifully coloured petals of Cattleya, the aesthetic appeal of orchids is obvious.

Continue reading the main story

Orchids: The bigger picture

Orchids are often referred to as indicators of a healthy eco-system

This is because many species are highly sensitive to disturbance

Orchids can only germinate due to their symbiotic relationship with a microscopic fungus so soil must be stable for them to grow

The plants also interact closely with invertebrates

Bee orchids (Ophrys) are named because their labellums mimic the appearance and scent of female bees, attracting males that then spread their pollen

• Watch David Attenborough explain how orchids need fungi to germinate

Throughout history the plants have been considered "overtly sexual" with voluptuous blooms sporting enlarged lips (labellum): pouting platforms to entice insect pollinators.

But the individuality and appeal of orchids also makes them vulnerable.

"Orchids are naturally rare with many species only being known from a handful of populations," says orchid expert Dr David Roberts from the Durrell Institute of Conservation and Ecology at the University of Kent, UK.

"Smuggling only effects the groups that are specifically in demand which isn't all orchids. However for the groups that are sought after, such as slipper orchids, it is a big problem."

High price

Rare species can fetch a pretty penny; a single stem of the Rotchschild's Orchid (Paphiopedilum rothschildianum), known as the Gold of Kinabalu, is reported to command prices of around $5000.

After its discovery in 1987 this slipper orchid, remarkable for its imposing horizontal petals, was stripped from the wild by orchid smugglers bringing it close to extinction.

Despite reintroduction of the plant from cultivated seedlings, it is still described as endangered and its few known wild locations in Kinabalu National Park in Sabah, Malaysia are kept a closely guarded secret.

However, not all species are afforded the same protection.

Orchids are naturally rare with many species only being known from a handful of

populations”

End Quote Dr David Roberts Durrell Institute of Conservation and Ecology

Last year, Asian orchid expert Dr Jaap J Vermeulen studied an orchid collected by conservationists in a national park in Sarawak, Malaysia.

But before he could describe the new species to science, it had been introduced to the black market.

"Bulbophyllum kubahense is a particularly beautiful species with a dense [cluster] of fairly large, white, heavily purple spotted flowers. That makes it desirable to orchid growers," Dr Vermeulen explains.

"Traders found the species in a conservation area, and first thought that is was a particularly luxuriant form of another, similar looking species... Plants appeared in nurseries in Sarawak, Singapore and Thailand."

Through his analysis, published in the journal Plant Systematics and Evolution, Dr Vermeulen confirmed that the plant was a "true novelty".

"It is beautiful, and it is rare: only known from a single locality near Kuching, Sarawak. That will put the price up, and with it the collecting pressure on the natural population," he warns.

Populations stripped

This is not the first time an orchid has been endangered before it has even been formally described.

Such is the demand from collectors, smugglers scour the globe for new species of orchid, sometimes removing whole populations of plants before anyone else knows of their existence.

Dr Vermeulen cites examples from peninsular Malaysia and Vietnam but the most famous example comes from Peru.

Phragmipedium kovachii was first found in 2001 and is referred to as one of the most important natural history discoveries of the last decade.

A foot tall with striking purple blooms, it is a distinctive member of the lady's slipper family, named for their slipper-shaped petal pouches.

Orchid dealer James Kovach bought the orchid from a roadside vendor in Peru and travelled back to his native US with it.

Within days, the Peruvian authorities asked the US Fish and Wildlife Service to investigate the plant, as all Phragmipedium are banned from export under the Convention on International Trade in Endangered Species (CITES).

This purple giant is one of the decade's top natural history discoveries

After its initial description, illegally plucked specimens of P. kovachii were reportedly changing hands amongst frenzied growers for as much as $10,000.

Kovach received two years probation and was made to pay a fine of $1000 for violating the endangered species act.

The orchid still bears the name kovachii but is now limited to a few authorised growers in Peru.

Although conservationists acknowledge the prosecution, they say the fines are not high enough to deter smugglers from their billion dollar enterprise.

"To a dedicated collector of wild-sourced orchids, price has no bearing," says Dr Richard Thomas, from the wildlife trade monitoring network Traffic International.

Dr Thomas says it is "notoriously difficult" to estimate the value of illicit trade.

Ruthless collection

According to Traffic's figures, the legal trade in live orchids in Europe alone involves more than 370 million plants.

An illustration of the rare Bulbophyllum kubahense

These orchids adhere to the CITES regulations: they come from licensed nurseries that hold the appropriate permits for international trade.

In these nurseries, single specimens are duplicated through micropropagation: creating thousands of cloned plants for the consumer market.

Despite advances, this process is costly and time-consuming.

The cloned plants are also considered inferior by collectors that value the variety in wild orchids' blooms.

"There are a small number of hard core 'collectors' for whom only a wild-sourced orchid will do, and they can be ruthless in their pursuit of this goal," says Dr Thomas.

"This can have a devastating impact on newly discovered species, where there is likely to be a demand created for the plant almost overnight."

Protecting the future

The UK's rarest orchid, Cypripedium calceolus, receives round-the-clock police surveillance where it grows on a Lancashire golf course.

But this level of protection is not globally consistent.

In the rainforests of South America and Asia, protecting individual species is an epic task.

Experts and customs officers join forces to protect vulnerable

Beyond the practical difficulties of surveying entire rainforests with limited resources, conservationists also have to contend with the pressures of developing nations.

According to the International Union for Conservation of Nature's orchid specialist group, tropical orchid habitat is vanishing as timber is removed, minerals mined and land cleared for roads and housing.

Some collectors insist that, by removing orchids from areas under threat from human development, they are protecting the future of species.

For some orchids, their only hope lies in ex-situ conservation: cultivation in nurseries is the only thing keeping species like Paphiopedilum vietnamenese from extinction.

In the interests of biodiversity however, conservationists maintain that orchids must be protected in their natural environment.

"For species with highly restricted ranges and severely threatened habitat, any removal of wild specimens poses a significant threat," says Dr Thomas.

"The loss of any one species is a tragedy - the world needs rich biological diversity to survive. Species have taken millennia to evolve, but can be lost in days."

First signs of ozone-hole recovery spotted

Antarctic ozone layer bouncing back after the phase-out of chlorofluorocarbons.

James Mitchell Crow

 

The average size of the Antarctic ozone hole in October 2010. Its recovery has so far been masked by annual fluctuations.NASA

The hole in the ozone layer over Antarctica is starting to heal, say researchers in Australia. The team is the first to detect a recovery in baseline average springtime ozone levels in the region, 22 years after the Montreal Protocol to ban chlorofluorocarbons (CFCs) and related ozone-destroying chemicals came into force.

Each spring, those chlorine- and bromine-releasing chemicals eat a hole in the ozone layer above the Antarctic. Thanks to the Montreal agreement, levels of anthropogenic ozone depleters detected in the region's stratosphere have been falling since around the turn of the millennium. However, detecting any corresponding ozone recovery has been difficult.

That difficulty is down to significant natural variations in average Antarctic stratospheric springtime ozone levels from year to year, which mean that the hole can be small one year and large the next. Scientists did not expect to be able to detect the gradual recovery of ozone for decades, masked as it is by these dramatic swings.

However, Murry Salby, an environmental scientist at Macquarie University in Sydney, Australia, and his colleagues have now shown how this annual fluctuation can be accounted for — and so removed from the data. They are left with the underlying systematic change in Antarctic ozone levels. Salby's calculations reveal that the levels are now rising; the findings are published in Geophysical Research Letters¹.

Ice in the air

The team's breakthrough was in showing that annual swings in average springtime ozone levels are linked to changes in a particular pattern of stratospheric weather known as dynamical forcing. In years in which this phenomenon is strong during the winter, more cold air is trapped above the pole. As a result, there are more ice crystals in the atmosphere. These crystals form the surface on which chlorine destroys ozone, catalysed by sunlight returning to the Antarctic during the spring.

"I think this is the first convincing observationally-derived evidence of the ozone rebound," says Adrian McDonald, an atmospheric scientist at the University of Canterbury in Christchurch, New Zealand. "It's the first where the statistical significance is high enough, and you can see the pattern well enough, that you feel comfortable in believing it."

Salby's results reveal a fast decline in ozone levels until the late 1990s, then a slow rebound that closely matches what theoretical calculations had predicted, says David Karoly, a climate scientist at the University of Melbourne, Australia. "It is the sort of result that was expected, but is the first to provide detection of an increase in Antarctic ozone levels," he says.

Adding weight to Salby's argument, the increase in ozone levels revealed by the calculations closely mirror the decrease in the levels of anthropogenic chlorine in the region. "For now, they agree pretty well," says Salby. "My feeling is that as time goes on we will start to see other influences on the systematic evolution of ozone level beside chlorine." One such influence is likely to be the increasing concentration of carbon dioxide in the atmosphere.

Slow change

Salby's data reveal that average springtime Antarctic ozone levels have already recovered by 15% since the late 1990s. However, projecting forward, natural weather-related fluctuations mean that even as late as 2085, ozone will still drop below 1980 levels for at least one year in every ten.

A complicating factor in that prediction is the influence of climate change, says Karoly. "Even when CFCs are removed, ozone levels will be different in the future than they were in the 1960s, because of changes in temperature in the stratosphere."

It's a relationship that goes both ways, however. "In the past four or five years it has become very clear that the ozone hole seems to have held back climate change over Antarctica," says McDonald. Ozone absorbs sunlight, so less ozone means the stratosphere heats up less. This has caused a change in circulation patterns around the Antarctic, which has trapped more cold air over the pole. As the ozone hole recovers, its future impact on Antarctic climate, and so on melting ice caps and global sea-level rise, is under debate.

"Some people are saying that, once the ozone hole totally recovers, because it has so far had a braking effect, maybe when that brake gets taken off then we'll have rapid change over the Antarctic. But there are many complexities in the system, and so other people are saying that it might not have very much effect. That is definitely work to be done by the climate-science community."

In the more immediate term, the strong correlation between winter weather patterns and springtime ozone levels means that the intensity of the ozone hole can now be forecast, says Salby. That is important because, at the end of each spring, the ozone-depleted air is released across the mid-latitudes of the southern hemisphere, affecting major population centres during the summer months by allowing increased levels of ultraviolet light to reach Earth's surface.

"If you know what the stratospheric forcing is during the winter, you can predict rather accurately the ozone level for the following spring," says Salby. 

The UK's bluebell woods will be at their most beautiful over the next two weeks, according to the National Trust. This early bloom was spotted at Downhill Demesne in Northern Ireland.

 

Next Image |

Previous Image |

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John Miller took this springtime photograph of the woods at Hatchlands Park in Surrey.a news.bbc.co.uk

Mystery bird: Hawai'i ʻAkepa, Loxops c. coccineus

Hawai'i ʻAkepa, Loxops c. coccineus, photographed at Hakalau Forest National Wildlife Refuge, Hawai'i (USA).

First meeting of the Transitional Committee for the design of the Green Climate Fund

Mexico City, Mexico
28 - 29 April 2011
In order to scale up the provision of long-term financing for developing countries, Governments at COP 16 in Cancun decided to establish a Green Climate Fund. A Transitional Committee selected by Parties to the UNFCCC, which will design the details of the new fund, met for the first time from 28-29 April 2011 in Mexico City, Mexico.

 May 2011 Last updated at 13:43 GMT

Rescue work in Guangxi province

A landslide triggered by heavy rain has buried more than 20 quarry workers in southern China.

Rescuers are digging through rubble in the search for survivors, according to the official Chinese news agency Xinhua.

The disaster happened in the village of Luojiang, near the city of Guilin, a popular tourist destination.

An area roughly the size of a football pitch was engulfed, including a dormitory used by the workers.

The landslide happened at 1330 local time (0530 GMT), according to a spokesman from the municipal government's flood control and drought prevention office.

Tourists stranded

A medical team has arrived at the quarry, but there is no word yet on casualty figures.

The incident followed a rainstorm at the weekend across the Guangxi Zhuang Autonomous Region, where the village is located. The local terrain features steep hills and thick jungle.

More than 10cm (4 inches) of rainfall was measured in Guilin on Saturday evening.

The nearby village of Zhongfeng was partially flooded, and around 70 residents were evacuated from their homes.

The rain also created problems when 130 tourists were briefly stranded at a countryside resort because of flooded roads.

 May 2011  

 

Most regions show a link between temperature rises and declines in crop yields

Shifts in the climate over the past three decades have been linked to a 5.5% decline in global wheat production, a study has suggested.

A team of US scientists assessed the impact of changes to rainfall and temperature on four major food crops: wheat, rice, corn and soybeans.

Climate trends in some countries were big enough to wipe out gains from other factors, such as technology, they said.

The findings have been published in the online edition of the journal Science.

"We focused on those four crops because they make up the bulk of calories consumed today," said research leader David Lobell from Stanford University.

"There are already clear changes going on in most agricultural regions in terms of weather, and they have effects on food production that are sizeable," he told the Science podcast.

"But in terms of temperature, we see that North America seems, oddly enough, to be exhibiting no real trend at all over the past 30 years.

"Whereas places like Europe, China and Brazil - pretty much the rest of the world, in terms of major agricultural production - have seen remarkable warming."

When the team assessed rainfall data, there were as many areas receiving more precipitation as were experiencing a decline.

"There seems to be no global trend at all," observed Professor Lobell.

Food for thought

The team carried out a large statistical analysis that tried to isolate the effects of temperature and precipitation on crops, independent of all other factors such as changes in technology and land management.

Wheat and corn are the staple crops that are most affected by changes in temperature

"We can see how much these variables affect crops... for example, for a crop like wheat, a degree (Celsius) of warming on a global average translates to about a 5% loss in production."

Professor Lobell said the study only referred to past relationships, as extrapolating the findings to predict future trends would require a number of assumptions to be made.

"In particular, you have to assume how non-linear the response will be and how different the crops of tomorrow will be from the crops of today," he said.

He added that the study focused on historical data in order to strengthen confidence in the existing projections.

"I think it is very clear that climate is not the predominant driver of change over long periods of time in crop production.

"Across the board, you see crop yields going up over the past 30 years, but the question is how much is climate modified (and) what would have happened if the climate was not changing.

"In some countries, we see that climate has only affected things by a few percent. In other countries, we see that yields would have been rising twice as fast.

"On a global average, we see that wheat production would be about 5% higher if we had not seen the warming since 1980. We see about the same for maize or corn.

"Yet for rice and soybean, we actually find that production is about the same as if climate had not been trending."