Dr. Peter P. Marra is the Dean of the Earth Commons—Georgetown's Institute for the Environment and Sustainability—and Laudato Si’ Professor of Biology and the Environment. His transformative work—including quantifying the loss of 3 billion birds from North America, the impacts of climate change, the astounding ecological destruction of outdoor cats and emerging diseases such as West Nile virus—explores the interaction between humans and our environment and poses critical questions to humanity about the environmental costs of urbanization and globalization.