Multi-scale approaches to global challenges in a telecoupled world

Global challenges such as water crisis, energy insecurity, biodiversity loss, land use change and climate change pose threats to the world's sustainability. Globalization enhances the connection of distant areas through various environmental and socioeconomic interactions. To solve the increasing challenges of achieving global sustainability in the context of globalization, the new telecoupling framework (socioeconomic and environmental interactions over distances) is proposed (Liu et al. 2013). A growing body of research has been exploring the dynamics, impacts, mechanisms, and structure of distant interactions involving global challenges. However, based on the telecoupling framework, we find no research that studies the evolution of multiple global environmental and socioeconomic interaction networks together. Also, the interactions between two kinds of distant virtual resource transfers simultaneously and the drivers of virtual resource transfers at the national scale are still unknown. Little research explores the evolution of virtual resource transfers at a national scale. The impacts of distant interactions on sending systems' sustainability at the regional scale has rarely been quantified and systematically analyzed. To address these knowledge gaps, I did the following work: First, I assessed the evolution of global telecouplings such as water, energy, land, CO2 emission, nitrogen emission and financial capital transfer networks and discussed how they have impacts on global water scarcity, energy crisis, land use change, global warming and nitrogen pollution. Second, I evaluated the interactions across two kinds of national telecouplings (interregional water and energy networks), and discussed their implications for the trading region's water scarcity and energy security, and explore the drivers of national telecouplings. Third, I studied the evolution of national virtual energy network. Fourth, I explored the water and food sustainability in a sending system of telecoupling (food transfer aimed at ensuring food security in the receiving system) at the regional scale. These four works have been accomplished in four chapters, respectively.Main findings from this dissertation include: At the global scale, the volumes of all these flows, except for land flow, increased over time. Financial capital flows increased most (188.9%), followed by flows of CO2 (59.3%), energy (58.1%), water (50.7%) and nitrogen (10.5%), while land transfer decreased by 8.8%. At the national scale using China as a demonstration, 40% of provinces gained one kind of resource (either water or energy) through trade at the expense of losing the other kind of internal resource (energy or water), and 20% of provinces suffered a double loss of both water and energy. The remaining provinces gained both water and energy. Over time, the total virtual energy transferred from energy-scarce to energy-abundant provinces increased from 43.2% to 47.5% from 2007 to 2012. At a regional scale, irrigated agriculture's annual water footprint in the North China Plain increased from 53 billion m3 in 1986 to 78 billion m3 in 2010. All counties faced unsustainable water use - local water consumption was greater than local renewable freshwater - even as the average crop water productivity increased from 0.90 kg.m-3 to 1.94 kg.m-3. These findings provide useful information for policy making to address environmental and socioeconomic challenges and build distant cooperation across multiple scales.