Several health risks and environmental events that are likely to be exacerbated by climate change are commonly identified in the literature: the emergence or re-emergence of infectious diseases, an increase in the frequency and intensity of extreme events, and profound changes to the environment and their health consequences. The French Institute for Public Health Surveillance has sought to clarify the current state of knowledge for each risk, identify existing surveillance and early warning systems, and address the new questions raised by climate change as well as the needs for knowledge and surveillance. The work was based on a review of the literature, expert consultations, and analysis of past events. The assessment of the health impacts of climate change remains qualitative, due to the limitations of available knowledge and significant uncertainties regarding climate and societal changes. For the risks considered (extreme events, environmental changes, and infectious diseases), data on the environment and health effects are derived from analyses of data provided by continuous surveillance systems or from the results of ad hoc studies. These surveillance and early warning systems must be strengthened by ensuring data quality and accessibility, and by improving the integration and consistency of environmental and health surveillance systems. A better understanding of risk-prone behaviors will also be essential for comprehending the impacts of climate change. Syndromic surveillance, which complements traditional surveillance systems, offers the advantage of providing useful information for crisis management and identifying unexpected events. It also appears necessary to foster interdisciplinarity to study complex systems and contextualize the health consequences of environmental, social, and economic changes. This need for interdisciplinarity is also reflected in interactions with research. Finally, taking into account the current health impacts of policies to mitigate aerosol and greenhouse gas emissions is also an important area for public health. Methods must be developed to provide decision-makers with the information they need to select policies that offer co-benefits (a direct positive impact on health in the short term and a reduction in climate change in the long term with an indirect positive impact). Surveillance could also be used to document and evaluate the consequences of these policies. (R.A.)