Prominent British and American sources now seek to structure public understanding of climate change by issuing "tipping point'' forewarnings of danger with increasing frequency. This emerging trend announces a shift in the way we are likely to perceive and respond to climate change dangers. This paper reviews key statements to suggest a significant dimension of this trend is its enrollment of epidemiological terminology to communicate urgent and uncertain threats. First, key events in the popular employment of epidemiological and public health models of explanation are reviewed. Second, the author discusses the climate change "debate'' to illuminate the limitations involved in treating climate change as a public issue detached from other problems involving atmospheric science. Third, the author reconstructs the tipping point tendency in this context. The essay concludes that the use of this concept signals a broader trend toward epidemiological models of explanation likely to activate public health styles of intervention for addressing climate change impacts. Some implications are briefly discussed.