Forecasting and assessing the large-scale and long-term impacts of global environmental change on terrestrial ecosystems in the United States and China

The Earth's terrestrial ecosystems have experienced a complex set of global changes, occurring on large spatial-temporal scales and interactively affecting individual organisms and ecological systems, most of which are not amenable to direct experimentation. To understand, predict, and assess the large-scale and long-term impacts of global changes on the Earth's terrestrial ecosystems, we need such a new approach for extrapolating the growth of plants, animals, or ecosystems into the future when climate, CO₂, and other factors may be different, and extrapolating individual plant or site studies onto a regional or global scale. In this chapter, we present such a newly developed approach called the Regional Integration System for Earth's ecosystem (RISE), which builds upon improved knowledge of the fundamental mechanisms of ecological systems, and supported by rapidly developing technology from high-speed computer systems to high-resolution remote sensing sources with global coverage. Then we apply the RISE to address our common understanding of perhaps the most important issue facing humankind in the twenty-first century, our disruption of the global carbon cycle. We use two case studies to illustrate the overall merits and applications of the RISE in terrestrial ecosystem research. In the first case study, the RISE has been used to predict and assess the impacts of global change on net primary productivity and ecosystem carbon storage in southeastern U.S. under current climatic conditions and future climate scenarios. In the second case study, we have used the RISE to assess changes in ecosystem carbon storage and fluxes induced by multiple environmental stresses including climate variability/change, land-use and land-cover change, elevated carbon dioxide, and air pollution in China.