What’s more, car owners are predicted to cut back on driving in order to save money. Together, these changes in consumer behaviour could make an important dent in the US contribution to global warming, reducing annual carbon dioxide emissions by tens of millions of tonnes per year. The impact will be dramatic, says Chris Knittel, an economist at the University of California, Davis, who was involved in one of the studies.

The changes are being driven by record fuel prices in the US, where, at the end of April, the average price of gasoline stood at $3.65 per gallon, 20 percent more than in January and treble the price of a decade ago. Until recently, these increases did not seem to be having a consistent effect on the car market and fuel use. Though sales of SUVs in the US have been falling over the past few years, this decline has come on the back of years of rapid growth, and overall gasoline consumption has been increasing every year since 1991.

That could be about to change. Knittel and colleagues looked at data on 1.4 million car purchases over the past 10 years, comparing sales patterns with gas prices. They found that sales of the least fuel-efficient cars, such as SUVs and pick-up trucks, fell by 13 percent for every $1 per gallon increase in the price of gasoline. The biggest SUVs suffered the most, with sales dropping by over 25 percent for every dollar by which the gas price rose. And for every $1 hike in gas prices there was a corresponding 17 percent sales boost for the most efficient vehicles, such as compact cars and hybrids. Knittel estimates that over about a decade, such changes in buying habits could cut the amount of gasoline used by US drivers by around 7 percent for every $1 increase in its price.

Knittel’s findings, presented last month at the University of California Energy Institute in Berkeley, are in broad agreement with those of economist Kenneth Small of the University of California, Irvine. Small looked at data on US fuel consumption and prices over the past 40 years, and projected last year that the recent doubling in fuel prices would quickly lead to a 4 percent drop in the total mileage covered on the roads. In the longer term, as drivers continue to react to rising prices, he projects the size of the reduction will grow to around 20 percent (The Energy Journal, vol 28, p 25).

This would lead to a substantial reduction in carbon emissions. Small says that a $1 per gallon rise in gasoline prices, roughly that seen over the past two years, will result in motorists using 14 percent less fuel in the long term. That would avoid the release of some tens of millions of tonnes of CO2 per year, equivalent to roughly 2 percent of the country’s greenhouse-gas emissions for 2006. That is a hugely significant drop, close to the level of cuts that some nations are required to make under the Kyoto protocol.

Small’s prediction comes with major caveats, however. Gasoline prices are not expected to return to the lows of a decade ago, but could fall by 10 or 20 percent in coming years. And any US economic recovery will boost fuel consumption, partly through raising incomes, which would dilute the pressure on motorists to drive less. So while expensive fuel will rein in consumption, Small and other economists question whether this will be enough to cause an overall fall in emissions from cars.

It is also possible that politics will intervene before any of these effects has a chance to kick in. Presidential hopefuls John McCain and Hillary Clinton have reacted to consumer protests over soaring fuel prices by declaring that they would suspend federal gasoline taxes. “It’s a fantastically stupid idea,” says Roberton Williams, an economist at the University of Texas at Austin.

“But people don’t like high gas taxes, so it’s popular.”

[Claire Bowles @ New Scientist]

The greater dwarf cloud rat (Carpomys melanurus) has dense, soft reddish-brown fur, a black mask around large dark eyes, small rounded ears, a broad and blunt snout, and a long tail covered with dark hair. An adult weighs about 185 grams.

“This beautiful little animal was seen by biologists only once previously ??C by a British researcher in 1896 who was given several specimens by local people, so he knew almost nothing about the ecology of the species,” said Lawrence Heaney, Curator of Mammals at the Field Museum and Project Leader. “Since then, the species has been a mystery, in part because there is virtually no forest left on Mt. Data, where it was first found.”

On 24 April, the research team completed its field work, the first comprehensive survey of the small mammals of Mt. Pulag National Park, according to Samuel Penafiel, the Regional Executive Director for the Philippine Department of Environment and Natural Resources for the Cordillera Administrative Region. Among the results was the capture of the dwarf cloud rat, which is a smaller relative of the giant clouds rats, spectacular animals found only on Luzon Island, but widespread and comparatively well known.

The dwarf cloud rat was captured by Danilo Balete, Project Co-Leader and Research Associate of the Philippine National Museum, in a patch of mature mossy forest (also called cloud forest) high on Mt. Pulag, at about 2,350 meters above sea level. It was in the canopy of a large tree, on a large horizontal branch covered by a thick layer of moss, orchids, and ferns, about 5 meters above ground, Balete said. “We had suspected from its broad, hand-like hind feet that it lived up in big trees, but this is the first evidence to confirm that.”

Since this is the first time the dwarf cloud rat has been seen in its natural habitat, the data collected from this specimen “will significantly augment our understanding of how these rodents evolved, what makes them tick, and how we can keep them around,” said William Stanley, Collections Manager of Mammals at The Field Museum. “Also, finding this animal again gives us hope for the conservation of one of the most diverse and threatened mammal faunas of the world.”

The research team thinks that this species probably lives only high in the big canopy trees in mature mossy forest, at elevations from about 2,200 to 2,700 meters, high in the mountains of the Central Cordillera. “Now that we know where to look for them, it will be possible to learn more,” Heaney said.

Much of the mossy forest in Mt. Pulag National Park where the biologists found the dwarf cloud rat was logged during the 1960s, and few large trees remain. The mossy forest has been gradually regenerating, but many local people now have vegetable farms there, and some of the mossy forest has disappeared as a result, according to Park Superintendent Emerita Albas. “Other parts of the park have extensive areas of mossy forest,” she said. “But where there are roads into the park, the vegetable farms are expanding. The people deserve to have a place to live and to have their farms, but the mossy forest needs to be protected.”

The mossy forest is like a giant sponge when it rains, soaking up the water and releasing it gradually. This produces clean water for irrigation, household use, hydroelectric dams, and industry in the lowlands. The mossy forest gets up to 5 or 6 meters of rain per year, or more.

Most of the species that the team documented on Mt. Pulag live only in the Central Cordillera, and most live only in mossy forests. Other unusual species documented by this research team during this survey are the bushy-tailed cloud rat, a spectacular animal of 1.5 kg with long, flowing black fur that they found to be common in mossy forest at 2,600 to 2,800 meters elevation, as well as three species of small rodents that feed primarily on earthworms. One of these small rodents was originally discovered by the same Field Museum research team and formally described as a new species only in 2006. Mt. Pulag is the only place currently known that has four species of cloud rats known to be present.

The team found that the pest rodents that cause damage around buildings and in the vegetable gardens on Mt. Pulag are not native species. Instead they are species, such as the Norway rat, that were accidentally brought to the Philippines centuries ago. The native species avoid humans, live in the forest, and cause very little if any economic damage. Some, like the dwarf cloud rat, probably are not able to withstand much disturbance of their natural habitat.

Cloud rats are one of the most spectacular cases of adaptive radiation by mammals anywhere in the world, with at least 15 species ranging in size from 2.6 kg to 15 grams, all living only in the Philippines. Cloud rats are a prime example of why biologists refer to the Philippines as “the Galapagos times ten,” Heaney said. “The Philippines may have the greatest concentration of unique biological diversity, relative to its size, of any country in the world.”

[Greg Borzogborzo @ Field Museum]

“People concerned with the effects of gas prices were significantly less attentive on the job, less excited about going to work, less passionate and conscientious and more tense,” Hochwarter said. “These people also reported more ‘blues’ on the job. Employees were simply unable to detach themselves from the stress caused by escalating gas prices as they walked through the doors at work.”

Hochwarter gleaned the information by surveying more than 800 full-time employees this spring when gas prices hovered at about $3.50 per gallon. All of the people surveyed work in a wide range of occupations, primarily in the southeastern United States. All drove personal transportation to work and had an average commute of 15 miles each way.

Survey respondents said gas prices were foremost on their mind, including a disgruntled factory worker who wrote, “I spend more time at work trying to figure out what I need to give up to keep gas in my tank than thinking about how to do my job.”

Hochwarter’s research will be submitted for publication later this summer. Among his findings:

• 52 percent have reconsidered taking vacations or other recreational activities

• 45 percent have had to cut back on debt-reduction payments, such as credit card payments
• Nearly 30 percent considered the consequences of going without basics including food, clothing and medicine
• 45 percent report that the escalating gas prices have “caused them to fall behind financially”
• 39 percent agreed with the statement “Gas prices have decreased my standard of living”
• About 33 percent — or one in three — said they would quit their job for a comparable one nearer to home

Hochwarter’s discussions with employees confirm the study’s results. Many employees report that gas prices rank as the No. 1 water-cooler discussion topic, ahead of family, sports or work, he said. He found little difference in responses among different ages, gender, work tenure and occupations.

“Several employees said they simply could not escape the media onslaught of bad news regarding the future of gas prices, and many reported their financial futures were looking bleaker and bleaker,” Hochwarter said.

As gas prices rise, so does the stress. Consider the words of Sandy, a medical records clerk: “The more it goes up, the more behind I get. If gas goes up to $5 or $6 a gallon, I just don’t know what I’ll do.”

[Wayne Hochwarter @ Florida State University]

The dime-sized laser, to be described Thursday, May 8, at the Conference on Lasers and Electro-Optics, emits 10 billion pulses per second, each lasting about 40 femtoseconds (quadrillionths of a second), with an average power of 650 milliwatts. For comparison, the new laser produces pulses 10 times more often than a standard NIST frequency comb while producing much shorter pulses than other lasers operating at comparable speeds. The new laser is also 100 to 1000 times more powerful than typical high-speed lasers, producing clearer signals in experiments. The laser was built by Albrecht Bartels at the Center for Applied Photonics of the University of Konstanz.

Among its applications, the new laser can be used in searches for planets orbiting distant stars. Astronomers look for slight variations in the colors of starlight over time as clues to the presence of a planet orbiting the star. The variations are due to the small wobbles induced in the star’s motion as the orbiting planet tugs it back and forth, producing minute shifts in the apparent color (frequency) of the starlight. Currently, astronomers’ instruments are calibrated with frequency standards that are limited in spectral coverage and stability. Frequency combs could be more accurate calibration tools, helping to pinpoint even smaller variations in starlight caused by tiny Earthlike planets. Such small planets would cause color shifts equivalent to a star wobble of just a few centimeters per second. Current instruments can detect, at best, a wobble of about 1 meter per second.

Standard frequency combs have “teeth” that are too finely spaced for astronomical instruments to read. The faster laser is one approach to solving this problem. In a separate paper, the NIST group and astronomer Steve Osterman at the University of Colorado at Boulder describe how, by bouncing the light between sets of mirrors a particular distance apart, they can eliminate periodic blocks of teeth to create a gap-toothed comb. This leaves only every 10th or 20th tooth, making an ideal ruler for astronomy.

Both approaches have advantages for astronomical planet finding and related applications. The dime-sized laser is very simple in construction and produces powerful and extremely well-defined comb teeth. On the other hand, the filtering approach can cover a broader range of wavelengths. Four or five filtering cavities in parallel would provide a high-precision comb of about 25,000 evenly spaced teeth that spans the visible to near-infrared wavelengths (400 to 1100 nanometers), NIST physicist Scott Diddams says.

Osterman says he is pursuing the possibility of testing such a frequency comb at a ground-based telescope or launching a comb on a satellite or other space mission. Other possible applications of the new laser include remote sensing of gases for medical or atmospheric studies, and on-the-fly precision control of high-speed optical communications to provide greater versatility in data and time transmissions. The application of frequency combs to planet searches is of international interest and involves a number of major institutions such as the Max-Planck Institute for Quantum Optics and Harvard Smithsonian Center for Astrophysics.

[Laura Ost @ National Institute of Standards and Technology (NIST)]