LAUSR

In our paper ‘‘Coupled Human and Natural Systems’’ (Liu et al. 2007), we developed a timely, theoretical, and practical foundation for research on Coupled Human And Natural Systems (CHANS). The science of CHANS builds upon, but goes beyond previous research that linked humans and ecosystems (e.g., ecological anthropology, environmental geography, human ecology). CHANS science uses a holistic perspective to integrate patterns and processes that connect human and natural systems, as well as within-scale and cross-scale interactions and feedbacks between human and natural components of such systems (Fig. 1). Such an integrated framework is needed to understand the increased complexity of the Anthropocene and develop innovative solutions to unprecedented global challenges. Over time, key ideas in this framework, in particular cross-scale interactions and feedbacks, also became incorporated into closely related concepts such as ‘‘socialecological systems’’ and ‘‘human-environmental systems’’. All three concepts are often used interchangeably, although formally the latter two are subsets of CHANS because CHANS includes not only social dimensions but also many other human dimensions (e.g., economic, cultural) that are not emphasized in the term of ‘‘social-ecological systems’’. Similarly, the CHANS framework emphasizes consideration of all aspects of nature including not only environmental processes in the term of ‘‘human-environmental systems’’ but also other dimensions (e.g., hydrological, climatic). We emphasize that the communities that use these various concepts overlap and that the concepts involved are not in contradiction, but simply note that the term of CHANS tends be the most encompassing. Since the publication of original CHANS ideas, research on CHANS has grown dramatically. In this essay, we offer a brief overview of the impact of our paper and highlight how the paper has inspired some later work such as telecoupling (Liu et al. 2013) and metacoupling (Liu 2017).