Cellphone use is "possibly carcinogenic to humans," the World Health Organization declared Tuesday, classifying mobile phones in the same cancer-risk category as lead, car exhaust and chloroform. A group of 31 scientists from 14 countries made the announcement after reviewing all relevant research, says Jonathan Samet, who heads the WHO's International Agency for Research on Cancer. Those studies point to a higher rate of malignant brain tumors in people who used their phones for about 30 minutes daily over a decade, especially those who "had the most intensive use of such phones," Samet says. "We simply don't know what might happen as people use their phones over longer time periods, possibly over a lifetime," he adds.

The WHO is careful to point out that no one knows for sure whether cellphones cause cancer, only that the data suggest a link is likely. "There is some evidence of increased risk of glioma" and another type of non-malignant tumor called acoustic neuroma, says the IARC's Kurt Straif. "But it is not at the moment clearly established that the use of mobile phones does in fact cause cancer in humans." It's not easy to prove such a link, neurobiologist Keith Black tells CNN, because cancer is a slow, complicated disease that's tricky to unravel. "The biggest problem we have is that we know most environmental factors take several decades of exposure before we really see the consequences," he says. And while cellphones don't emit ionizing radiation like X-rays, their subtler non-ionizing radiation can still cause damage, he adds. "What microwave radiation does in most simplistic terms is similar to what happens to food in microwaves, essentially cooking the brain," Black says. "So in addition to leading to a development of cancer and tumors, there could be a whole host of other effects like cognitive memory function, since the memory temporal lobes are where we hold our cell phones."

There are more than 5 billion cellphone subscriptions worldwide, so the chance they might cause cancer has not surprisingly stirred up some global anxiety. There are ways to reduce your risk without giving up your phone, though — Apple recommends holding the iPhone at least 5/8 of an inch away from the body when transmitting, for example, and the BlackBerry Bold's instructions suggest just under 1 inch of distance when the phone is in use. Using a wired headset, Bluetooth earpiece or speakerphone can help, as can texting instead of talking. And phones also emit more radiation when they're moving quickly, adding yet another reason not to talk and drive. 

(Sources: Reuters, CNN, Agence France-Presse)


The space shuttle Endeavour glided back to Earth through the predawn darkness this morning (pictured), touching down in Cape Canaveral, Fla., to end its 16-day mission in space as well as its 19-year career. The landing came at 2:34 a.m. on Kennedy Space Center's Runway 15, leaving Endeavour with 25 missions under its belt and 122 million miles on its odometer — and leaving NASA with just one active space shuttle remaining in its fleet. 

"Welcome home, Endeavour," Mission Control radioed to the shuttle's crew after the landing. "Thank you, Houston," replied Endeavour commander Mark Kelly. "On behalf of my entire crew, I want to thank every person who's worked to get this mission going and every person who's worked on Endeavour. It's sad to see her land for the last time, but she really has a great legacy." Endeavour's final mission involved carrying a $2 billion cosmic-ray detector up to the International Space Station, one of many key components it has delivered to the ISS over the years. The youngest of NASA's shuttles, Endeavour made 12 visits to the orbiting station during its 25 flights, including a mission in December 1998 to deliver and attach the station's first U.S. segment, the Unity node. Now that the shuttle is back on terra firma for good, however, it must transition from the exciting life of space explorer to the relatively mundane existence of a museum relic. After NASA decommissions and decontaminates Endeavour, it will settle into its new home at the California Science Center in Los Angeles. "It's very bittersweet," co-pilot Gregory Johnson tells "This vehicle is a wonderful machine and it's an honor and a privilege for each one of us to be a part of her final flight."

NASA is ending its 30-year shuttle program this year as part of a broad strategy shift at the space agency. Commercial firms like SpaceX and Virgin Galactic are poised to take over routine space flight in coming years, freeing up NASA to focus on bigger-picture missions like exploring Mars and asteroids. The last remaining space shuttle in NASA's fleet, Atlantis, is scheduled to take off on its final mission July 8.

(Sources:, Associated Press)


The 2011 Atlantic hurricane season officially kicks off today, ushering in a new threat even as the U.S. is still reeling from a historic tornado season. But as the AP reports, this won't be an easy hurricane season to forecast, due to mixed messages from El Niño and La Niña, two major influencers of tropical cyclones in the Atlantic. "With a strong La Niña or El Niño year, the forecast is much easier," AccuWeather meteorologist Dan Kottlowski tells the AP. "Since we don't have a strong signal toward El Niño or La Niña, there's somewhat more uncertainty in trying to determine how strong this season will be."

As of May 19, the National Hurricane Center in Miami is predicting an above-average season, with up to 18 named storms developing, and three to six of them becoming major hurricanes. Another prominent group of hurricane forecasters at the University of Colorado expects 16 named storms in 2011, including nine hurricanes, two of them major. (The seasonal average is 11 named storms, six hurricanes and two major hurricanes.) El Niño typically reduces the chance of a strong Atlantic hurricane season by creating heavy wind shear over the western Atlantic Basin, ripping apart many cyclones before they can fully develop. La Niña tends to have the opposite effect, limiting wind shear and making it easier for hurricanes to form. There is no El Niño this year, and while La Niña has been wreaking havoc for months — likely contributing to last year's active hurricane season, and possibly even this year's heavy blizzards and thunderstorms — it remains unclear how much longer it will last. Its effects are expected to fade sometime this month or next, although its weather effects could linger for months, the federal Climate Prediction Center warns.

People along the Gulf Coast are hardly in a position to handle a destructive hurricane, thanks to last summer's Gulf oil spill and this year's historic flooding along the Mississippi River. Much of the Southeast has also been battered by severe thunderstorms and tornadoes in recent weeks, leaving entire cities like Joplin, Mo., and Tuscaloosa, Ala., in shambles. The best advice for everyone within hurricane range, Kottlowski tells the AP, is to pay attention to seasonal forecasts but not rely on them. "You prepare for the worst, regardless of what the forecast is," he says.

(Sources: AP, OurAmazingPlanet)


Japan's nuclear crisis was enabled by governmental and corporate overconfidence, according to a new report by U.N. inspectors. Japanese authorities and the Tokyo Electric Power Co. both underestimated the risk of a tsunami cutting electricity to coastal reactors, says the International Atomic Energy Agency, although their response since the March 11 earthquake and tsunami has been "exemplary."

The IAEA report also calls for tougher regulation of Japan's nuclear industry, arguing measures should be taken to ensure that "regulatory independence and clarity of roles are preserved in all circumstances." This echoes a common criticism in Japan, the New York Times reports, that government regulators had become too friendly with the industry, allowing safety lapses to fester at the Fukushima Daiichi nuclear plant. The report also comes as Japanese Prime Minister Naoto Kan is facing a no-confidence vote in Parliament, submitted by three opposition parties over his handling of the crisis. Some members of Kan's own party are backing the motion, the BBC reports, and if it's approved on Thursday, the prime minister would be forced to either resign or call a "snap election." Kan is expected to survive the vote, the Times reports, but it does signal growing frustration over the government's inability to curb the crisis. "What is most sought by the people is for us to work together to achieve reconstruction and resolve the nuclear crisis," Kan said during a recent parliamentary debate. "I must respond to their needs, and that is my responsibility."

The IAEA's report followed a weeklong inspection at Fukushima Daiichi, and most of the problems it cites have already been documented during the nearly three months since the disastrous earthquake and tsunami. But while the country was ill-prepared before the catastrophe occurred, the IAEA inspectors are impressed with its resolve and quickness during the past 12 weeks. Emergency workers' efforts to gain control of the broken reactors produced "the best approach to securing safety given the exceptional circumstances," according to the report, while the government's speedy evacuations of nearby residents were "impressive and extremely well-organized."

(Sources: New York Times, BBC News)


The Grand Coulee Dam blocks salmon runs, zebra mussels invade the U.S., and more.

Russell McLendon

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Photo (human skull with cellphone): Getty Images

Photo (Endeavour landing on June 1): NASA

Photo (Hurricane Isabel in 2003): NASA

Photo (Fukushima Daiichi plant): ZUMA Press

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