Today is officially the first day of spring, but spring has been gradually shifting into winter, the AP reports. Signs of spring—trees flowering, animals coming out of hibernation—are coming earlier every year. The shifting season has biologists seriously worried. "The alarm clock that all the plants and animals are listening to is running too fast," said one.
Spring's shift earlier is one of the clearest signs yet of global warming, and many biologists fear that the changes could play havoc with ecosystems and wipe out entire species. Early spring spells trouble for humans, too—allergy seasons are getting longer and stronger. "It's a huge health impact," a professor said. "17% of the American population is allergic to pollen."