Climate changes, particularly global warming, are attributable to human activities, mainly fossil fuel burning which releases greenhouse gases such as CO₂. The emissions of CO₂ continue to rise, and climate models project 1.1℃ to 6.4℃ rise of average surface temperature over the 21^st century. Health effects from global warming range from increased mortality by extreme weather, floods, and storms to increase of diseases such as malaria, dengue fever, and diarrhea. Korea is not immune to health impacts from global warming. Data on daily temperature of Seoul in 1994 showed a clear association with daily mortality. Rise of sea and surface temperatures also indicates possibility of increase in infectious diseases in Korea. Concentrations of ambient pollutants, particularly ozone, were shown to be associated with surface temperature. Therefore, we are already in the influence of climate change. Adaptation strategy to climate changes is basically a matter of public health. Well-prepared programs for responding to climate changes will minimize health risks. The most effective responses are strengthening of the key functions of environmental management, surveillance, and response to natural disasters and changes of disease patterns associated with global warming. We need to intensify our efforts in preventive public health, and ensure sustainable development and protection of ecosystem for human health.