Climate change affects many natural and social systems and processes that are essential for life. It disrupts the Earth’s life-support systems that underpin the world’s capacity to supply adequate food and fresh water, and it disturbs the eco-physical buffering against natural disasters. Epidemiologists need to develop and improve research and monitoring programs to better understand the scale and immediacy of the threat of climate change to human health and to act within a much larger and more comprehensive framework. To address one of the greatest environmental issues of our lifetime, the scientific and policy-making communities should work together to formulate evidence-informed public policy to mitigate greenhouse gas emissions and adapt to its inevitable impacts in this generation and, more importantly, in future generations to come.