Climate change is one of the most important direct drivers of biodiversity loss and change in ecosystem services. Climate warming affects many traits at the individual level such as metabolic rate, nutritious quality, and phenology. In theory, it may in turn change trophic and ecological interactions, affecting population and community dynamics through bottom-up and top-down regulations. It may also lead to nonlinear transition of ecosystem states. In reality, however, it is important to understand how the response of ecosystems is different between climatic regions and between aquatic and terrestrial ecosystems. In this talk, I will first review regional variations of climate in a region from Northern Japan to Southern Taiwan. For example, the annual average temperature ranges from 8.9 (in Sapporo), 16.3 (in Tokyo), 23.6 (in Taipei), to 24.7 ^oC (in Kaohsiung). The annual average sea surface temperature ranges from 5 to >25 ^oC. Second, I will review regional variations of trends in climate change (e.g. those of temperature and precipitation) that are already observed and are projected to emerge in East Asia. Third, I will summarize the current hypotheses on the regional variations in the responses of each level of ecological organizations (population, community, and ecosystem) to climate change.