Coupling humans and nature at regional scales

Background/Question/Methods: The key to achieving environmental sustainability hinges on our ability to understand the reciprocal interactions between humans (H) and the environment (E). Although it is well-known that coupled H-E systems vary with spatial and temporal scales, most of our basic scientific knowledge comes from small spatial studies conducted over short time periods. There is a critical need to conduct systems-oriented research on Coupled Human and Environmental MacroSystems (CHEMS) in order to understand and forecast the consequences of climate, land use, and socioeconomics at regional to continental scales. Based on our CHEM concept, this synthesis paper aims at elucidating key commonalities in environmental sustainability across selected regional and continental scales. Our overarching question is: What are the trends in the relationship between environmental sustainability and economic development between and within the CHEMS at specified spatial scales? 

Results/Conclusions: On the Mongolia Plateau, we compared the CHEMS between Inner Mongolia (IM) and Mongolia and found that the two governments had undergone similar changes in population, economy, and livestock, with changes in IM occurring at a much higher rate. Some of the socioeconomic measures are potentially related to regional climate change; however, the correlation may also vary by other geophysical settings. Across Dryland Eastern Asia (DEA), the five administrative units were studied for coupled relationships among social, economic, demographic, and ecosystem dynamics over the past five decades. An increasing number of studies have shown that the two drivers regulated ecosystems simultaneously, with human disturbances producing much stronger impacts than climate change. Here, we found that the contributions of climate and land use on GPP and ET indicated that land use was responsible for 64.3% and 83.6% of GPP and ET variation, respectively, while climate explained only 26.8% and 14.5%, respectively. Additionally, the institutional responses to ecosystem degradation have been generally positive in restoring or preserving grassland ecosystems through national policy and regulations; however, the societal implications of these national programs have been not been fully assessed. Finally, the USA and China, as two macrosystems, are the world’s major greenhouse gas emitters and are similar in size, latitude, and physical gradients in the southeast-northwest direction. These two countries differ widely with regard to politics, socioeconomic factors, demography, and culture. We proposed a working hypothesis that environmental sustainability and the function, structure, and resilience to global change of the CHEMS will vary along gradients of changing biophysical and socioeconomic characteristics from regional to national scales.