This article proposed the concept of "climate capacity" as a way of measuring human's adaptiveness to climate change. This article also focused on the related concepts like ecological carrying capacity, water resources carrying capacity, land carrying capacity as well as population carrying capacity. The concept of climate capacity was articulated against a background of global climate and environmental change. Essentially, China's efforts to adapt to climate change was a matter of improving climate capacity, which is the ecosystem as well as the frequency, the intensity and the scale of human's social activities that the climatic resources of a particular geographic area were supposed to support. The climate capacity has two components. One is the natural climate capacity, which includes temperature, sunlight, precipitation, extreme climatic events, etc. The other is the derived climate capacity, which includes water resources, land resources, ecological systems, climatic risks, etc. The climate capacity can be developed or be transferred between regions by taking engineering, technology or regime-based adaptive measures. However, these adaptive measures must be implemented under the principle of economic rationalism, ecological integrity, climate protection, and social justice. It is expected that by combining the climate capacity and its threshold value with the assessment of climate change risks, we are able to predict the optimal population carrying capacity and the scale of socioeconomic development, and furthermore, provide policy support for the socioeconomic development strategy and adaptive planning. In the regions with high climate capacity, there is a symbiotic relationship between adaptation and socioeconomic development. But, in the regions with limited climate capacity, irrational development may further damage the environment. Taking the Yangtze River delta, a region with high climate capacity, and a region of Ningxia, a region with limited climate capacity, as illustrative examples, the authors of this article analyzed the policy implications of climate capacity and further made suggestions on the problems of capacitylimited adaptation and development-driven adaptation. This article argued that the concept of climate capacity can not only be used as an analytical instrument of climate change economics, but also it can provide research support for planning regional adaptation and development with climate change impact and risk assessments.
