CNN: President Barack Obama spoke in front of one of Yosemite National Park's picturesque waterfalls on a sun-splashed Saturday touting the importance of America's parks, but cautioning the threat of climate change is real and affecting the planet now. The President and first family are visiting Yosemite to mark the 100th anniversary of the National Park system. The Obama's visited Carlsbad Caverns National Park in New Mexico on Friday. In a speech with a small group of onlookers in front of the falls,...