The earth is a complicated place.  Cause and effect often take circuitous routes, thanks to a variety of ecological, atmospheric and geologic feedback loops that often take surprising turns.  That makes modelling the effects of climate change peculiarly difficult. For example, if you were an animal that eats grass, you might think that warmer temperatures and a longer growing season would mean happy days for you.  Lots of grass, lots to eat, you’re a happy grasshopper. But, as it turns out, that might not necessarily be so. Ellen Welti, is a Post-doctorate Fellow in The Kaspari Lab at Oklahoma University and she joins us now by phone.