It's impossible to pinpoint exactly when, but gradually this century, global warming has moved from being the hypothetical doomsday rant of a few climate scientists to the No. 1 environmental concern of ordinary Americans. In North Carolina and elsewhere, people see signs of global warming -- real and imagined -- all around them. It's blamed for warm weather in January, for palm trees growing in Raleigh, for hurricanes, beach erosion, bug infestations and everything in between.
But the real effects of global warming are still highly speculative. Most scientists agree that the world's temperatures are rising, and that the increase can be linked to man-made greenhouse gases from cars, power plants and other industrial sources.
There is less consensus, however, about how warmer temperatures will affect people in specific communities. And some scholars still question how much of the rising temperatures can be linked to human activities.
Additional research will help to clarify the issue, but two prominent scientists have agreed to explain their interpretation of the current evidence for The News & Observer.