Dr. Katharine Hayhoe is not a climate pioneer like Al Gore or a street-marching activist like Bill McKibben or a geek icon like Bill Nye. But she has emerged as one of the nation’s most effective communicators on the threat of climate change and the need for action. She lives and works out here in West Texas, but lately seems to be everywhere, kicking off a series of “Global Weirding” videos, posting on Twitter and Facebook, and speaking anywhere from local churches to international conferences. Last week, she appeared at the White House to discuss climate change with President Obama and the actor Leonardo DiCaprio at the first South by South Lawn ideas festival.