I take leave of my companions to get ready for my return early the next morning. They will stay on for another week and complete this year’s field expedition. It has been an exhilarating experience, one of learning and revelation. I return to Washington with a deeper appreciation of what it is like to work in the field as a paleontologist—the joy of finding fossils, the excitement of interpreting what they say about this important event, and how, after 55 million years, new knowledge about how our planet works is coming from a study of its past.
I also better appreciate how important this work is. We are ourselves facing a period of global warming of similar magnitude but much greater rapidity than that of the PETM. We do not yet know what amount of warming might trigger release of carbon from additional reservoirs, and we do not know if we can slow or stop these releases if they begin. By revealing how our complex and interconnected planet changes with rapid warming, understanding what happened 55 million years ago can help those of us in our time understand what we might face in the future. The creatures that existed during the PETM did not include six billion humans, but the lessons we learn from observing those long-ago climatic and ecological changes are likely to be helpful to all of us and our descendants.