Inside Science News Service

A collection of brief stories from the world of science

By Jim Dawson
Inside Science News Service
September 5, 2008

Oceans Warmer, Hurricanes Stronger

One of the long-standing predictions of global warming research is that extreme climate events will become more frequent. But in a system as complex as the Earth’s climate it is difficult to tie individual events together into trends and then link those trends to global warming. One of the most intense debates in the science community has been about the theory that global warming is contributing to stronger extreme weather events like hurricanes and cyclones. New research from Florida State University bolsters the contention that the strongest tropical cyclones are getting stronger and links them to an ocean that is warming because of global warming. The research, by a team lead by FSU geographer James Elsner, is based on a “heat-engine” theory put forward by MIT scientist Kerry Emanuel in 2005.

That theory, in its simplest form, says that as seas warm, the ocean has more energy that can be converted to tropical cyclone wind, which makes hurricanes stronger. (Emanuel, in a recent paper, modified much of his work predicting that heat engines will trigger more hurricanes, but noted that global warming might still play a role in raising the intensity of hurricanes, which is the focus of Elsner's research). Elsner and his team looked at 30 years of data and focused on storms that were closest to the maximum possible intensity, or as strong as they could be given the environmental conditions. They found that the strongest tropical cyclones are getting stronger, particularly over the North Atlantic and Indian oceans. Wind speeds in the strongest storms increased from an average of 140 miles-per-hour in 1981 to 156 miles-per-hour in 2006. During this period the ocean temperature, averaged globally over all the regions where tropical cyclones form, increased from 82.7 to 83.3 degrees Fahrenheit.

“By looking only at the strongest tropical cyclones, where the relationship between storms and climate is most pronounced, we are able to observe the increasing trends in storm intensity that both the theory and models say should be there,” Elsner said. The research appeared in a recent issue of the journal Nature.

The More the Bicycles, the Fewer the Bicycle Accidents

In a study that at first glance seems counterintuitive, researchers at the University of New South Wales in Sydney, Australia reviewed safety studies from 17 countries and 68 cities in California and found that the more people bike in a community, the less they collide with motorists. “It appears that motorists adjust their behavior in the presence of increasing numbers of people bicycling because they expect or experience more people cycling,” said Julie Hatfield, and injury expert from the university.

With fewer accidents, people perceive cycling as safer, so more people cycle, thus making it even safer, she said. “Rising cycling rates mean motorists are more likely to be cyclists, and therefore be more conscious of, and sympathetic towards, cyclists,” she said. Safety experts said the decrease in accidents that comes with an increase in cycling is independent of improvements in cycling-friendly laws and better infrastructure such as bike paths.

The safety studies reviewed were from Australia, Denmark, the Netherlands, 14 other European countries, and 68 cities in California. Although the review focused on bicycling, it appears that the more is safer rule also applies to pedestrians, Hatfield said.

Study Einstein, Eat Donuts

People engaged in “intellectual work” tend to eat more, which, according to a recent report in Psychosomatic Medicine, a phenomenon that, according to the Canadian researchers who conducted the study, could “go some way to explaining the current obesity epidemic.” The scientists, with the Université Laval in Quebec City, measured the spontaneous food intake of 14 female students after each of three 45 minutes periods in which they were first asked to sit down and do nothing, then read and summarize a text, and finally complete a series of memory, attention, and vigilance tests on a computer.

Earlier research had shown that about 45 minutes of intellectual work only burns three extra calories compared to resting, so the students didn’t physically need to run for the buffet after using their brains. But they did. Despite the low energy cost of mental work, the students spontaneously consumed 203 more calories after summarizing a text and 253 more calories after the computer tests - and increase of 23.6 percent and 29.4 percent respectively compared to the rest period.

“Caloric overcompensation following intellectual work, combined with the fact that we are less physically active when doing intellectual tasks, could contribute to the obesity epidemic currently observed in industrialized countries,” said research Jean-Philippe Chaput. “This is a factor that should not be ignored, considering that more and more people hold jobs of an intellectual nature.”

A Cigarette, a Cup of Coffee, and . . .

Scientists have long known that nicotine is the powerful, addictive drug in cigarettes, but a Kansas State University psychologist has done research that suggests it may be the way nicotine enhances all those little, and not so little, pleasures in life. A cigarette, according to Matthew Palmatier, may actually make that cup of coffee taste better to the smoker.

“If you think about where people smoke or who they smoke with, you realize that it occurs in very specific places, often with a specific group of people,” he said. “Maybe it’s a reason why nicotine is so addictive. If you get used to having that extra satisfaction from things you normally enjoy, not having nicotine could reduce the enjoyment in a given activity.” Palmatier, working with a grant from the National Institute on Drug Abuse, noted that patches and pills help with the physical addition, but quitting smoking remains extremely difficult.

“There are a lot of health risks, and the majority of smokers already know what they are. They want to quit but can’t. It’s not because nicotine is a potent drug. It doesn’t induce significant amounts of pleasure or euphoria.” In one of a series of tests he conducted with rats, Palmatier discovered that the rodents who had been dosed with nicotine responded more to rewards of sugar water.

“The taste aspect is really important because we can actually figure out how nicotine is increasing the subject’s behavior,” he said. “If it makes a reward more pleasurable, then it may increase the palatability of a sweet taste.”

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