Climate change involves the long-term and far reaching effects of shifts in the planet's weather, specifically those caused by the effects of global warming due to human activity. In addition to warming and changed weather patterns, climate change will increasingly spark extremes in weather -- a greater frequency and intensity of storms, heat and cold. These changes will have profound effects upon human environments, ecosystems, economies and, in the end, life. These changes increasingly generate drought, flooding and natural disasters that lead to crisis situations -- epidemics, malnutrition, forced displacement and the destruction of the basic necessities to life. Critically, the effects of climate change exacerbate the scarcity of key resources, and hence contribute to armed conflict and impoverishment. The challenge to humanitarian action is to respond to its consequences while at the same time contributing to addressing its causes.