"We live in a microbial world. Microbes run this planet. Microbes have been around for billions of years before plants and animals evolved. All of the major biogeochemical functions on this planet came about because of microbes, and continue to be run by microbes. So when you talk about something like climate, the major biological influence of climate - aside from anthropomorphic changes, of course - have always been microbes." -David Mark Welch