Fox: President Obama on Saturday broke from his family vacation in Yosemite National Park to urge Americans to act on climate change, which he argued is destroying the countrys precious natural resources. Make no mistake, climate change is no longer a threat, its a reality, the president said in a roughly 10-minute speech, ahead of the upcoming 100th anniversary of the National Parks system. Obama said Yosemite rangers told him that signs of climate change, or global warming, are already occurring...