The background atmospheric concentration of carbon dioxide has reached 400 ppm, and warming of the climate system is unequivocal (IPCC AR5). As various influences of climate change on agriculture are becoming apparent, climate change studies in agriculture should be accelerated. Division of Climate Change is a new division of NIAES for investigating various issues on climate change in the agricultural sector. We assess the impacts of climate change on national and global crop production, and develop efficient agricultural production technologies for climate change adaptation. We also develop effective measures for mitigating global warming by reducing greenhouse gas emissions from crop fields. Our ultimate goal is to contribute for setting a vision for agriculture under climate change. Although our study topics cover wide spatial and temporal scales from understanding mechanism on a cell scale to assessing the impacts on national and global scales, it is common to elucidate responses, including feed-backs, of a system of interest (a plant, soil, agro-ecosystem, or food demand-supply system) to climate change. To tackle these issues, we also promote understanding fundamental processes, such as plant photosynthesis and decomposition of organic matter in soil because results of those studies are the basis of our research on climate change.