Final answer:
Global warming causes positive feedback where warming feeds on itself, resulting in accelerated climate change and a potential run-away greenhouse effect.
Step-by-step explanation:
Global warming causes positive feedback, where warming feeds on itself. Positive feedbacks in global warming include factors such as a warmer planet resulting in less reflected sunlight and increased solar forcing, warmer air holding more water vapor and driving up the greenhouse effect, and accelerated ice melt due to darker water pools on top of the ice. These positive feedback effects accelerate climate change and can lead to a "run-away greenhouse effect."