A U.N. scientific panel warns that killer heat waves, wildfires, droughts and floods will threaten lives, the economy and world peace, and worsen problems such as violence, poverty and illness. Climate change has gotten so bad that the Intergovernmental Panel on Climate Change added a new level of risk — "very high," NBC News reported. Report co-author Maarten van Aalst said this risk level might as well be called a "horrible."
