Grasslands cover about 40.5% of the world's terrestrial area (Suttie et al., 2005) and provide important ecosystem services, such as supporting a variety of animals and plants. Climate change may have profound impacts on grasslands. Such impacts must be fully understood in order to mitigate climate change impacts and maintain grassland ecosystem functions and services throughout the world. There are dozens of manipulative experiments that have been set up in grassland ecosystems worldwide to explore how climate warming would affect them. In this chapter, we synthesize the current knowledge from these manipulative experiments. We focus on the responses of plants and microbes to experimental warming, carbon (C) and nitrogen (N) cycles as affected by experimental warming, and modeling studies on grassland ecosystems in response to warming. [link to publication]