Is global warming causing more extreme weather? Many people seem to think that the last decade's heat waves, hurricanes and droughts did not happen just by chance, but were linked to the phenomenon of global warming. In 2003, for instance, a ferocious heat wave settled unexpectedly across Europe and killed 35,000 people. Nobody saw it coming. 'There was some panic, simply because the event was virtually unprecedented," says Jerry Mahlman, senior research associate at the U.S. National Center for Atmospheric Research. "Nonscientists believed this was the definitive 'proof that global warming had arrived." And this was only one example. The list keeps growing. Last year, there were floods in India, Nepal, Bhutan and Bangladesh that have been described as the worst in living memory. An abnormal volume of monsoon rains killed over 2,000 people and left about 30 million homeless. In the same year, consecutive heat waves gave rise to more than 3,000 forest fires in Greece, killing more than 80 people. In 2006, Europe experienced exceptionally hot weather, which resulted in 3,418 deaths all over the Continent. In 2005, Hurricane Katrina was one of the most devastating hurricanes ever recorded in the United States, killing more than 1,800 people and causing $81 billion in damage. In 2004, furious storms in the Philippines killed 669 people, with another 695 listed as missing. With or without the help of humankind, the earth's atmosphere produces substantial variations on its own, says Mahlman. Nonetheless, global warming is here