National Public Radio: Most climate models a bleak picture of the Great Plains a century from now as a hot region besieged by heavy rainstorms and flooding. And new studies suggest that climate change may bring farmers another headache: more invasive plants. Ask most Midwestern and Rocky Mountain ranchers about the weeds they pull their hair out over and be prepared for . There's cheat grass in Nebraska, red brome in Utah and yellow star thistle in California. And they can't count on cattle to gobble them up. Depending...