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.