CNN: Human activity has caused at least half of climate change in the last half-century, hundreds of scientists say. They are 95% certain of this, the surest they've ever been, says a United Nations report published Friday. That activity? Driving cars, running power plants on coal and oil, torching swathes of forestland and debris; anything involving burning carbon-based fuels and emitting greenhouse gases. We are seeing the consequences already in extreme weather patterns, particularly drought and...