Like every institution that uses energy, consumes resources, and engages in construction or renovation, libraries have an impact on the environment and on the critical problem of climate change. Taking action to protect library collections is not only an idealistic professional goal but also a very practical one. Disaster preparation measures and the reduction of greenhouse gas emissions through energy conservation can save money, time, and resources. This article describes the various preservation threats to libraries and strategies for dealing with them. These threats include compromised air quality, water, chaotic weather, and climate change. (Contains 22 online resources.)