Fast-growing urban areas worldwide, especially in developing countries, will suffer disproportionately from impacts of changing climate, a U.S. researcher says. An examination of urban policies by Patricia Romero Lankao at the National Center for Atmospheric Research says cities worldwide are failing to take necessary steps to protect residents even though billions of urban dwellers are vulnerable to heat waves, sea level rise and other changes associated with warming temperatures, an NCAR release said Thursday. "Climate change is a deeply local issue and poses profound threats to the growing cities of the world," Lankao says. "But too few cities are developing effective strategies to safeguard their residents." Most cities are also failing to reduce emissions of carbon dioxide and other greenhouse gases that affect the atmosphere, she says. Scientists say they are increasingly concerned about the potential impacts of climate change on cities, now home to more than half the world's population. Their locations and dense construction patterns often place their populations at greater risk from natural disasters, they say, including those expected to worsen with climate change. "What is at stake, of course, is the very existence of many human institutions, and the safety and well-being of masses of humans," Lankao says.