Assessing progress towards sustainable development over space and time.

To address global challenges1-4, 193 countries have committed to the 17 United Nations Sustainable Development Goals (SDGs)5. Quantifying progress towards achieving the SDGs is essential to track global efforts towards sustainable development and guide policy development and implementation. However, systematic methods for assessing spatio-temporal progress towards achieving the SDGs are lacking. Here we develop and test systematic methods to quantify progress towards the 17 SDGs at national and subnational levels in China. Our analyses indicate that China's SDG Index score (an aggregate score representing the overall performance towards achieving all 17 SDGs) increased at the national level from 2000 to 2015. Every province also increased its SDG Index score over this period. There were large spatio-temporal variations across regions. For example, eastern China had a higher SDG Index score than western China in the 2000s, and southern China had a higher SDG Index score than northern China in 2015. At the national level, the scores of 13 of the 17 SDGs improved over time, but the scores of four SDGs declined. This study suggests the need to track the spatio-temporal dynamics of progress towards SDGs at the global level and in other nations.

Evolution of multiple global virtual material flows.

The world is connected through multiple flows of material, but a comprehensive assessment of their temporal dynamics and interactions is rare. To address this knowledge gap, we assessed the evolution and interactions of global flows of virtual water, energy, land, CO2, nitrogen as well as financial capital embodied in international trade from 1995 to 2008. We found that 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%. Volumes of virtual material flows among distant countries were much higher than those among adjacent countries. The top five countries accounted for a surprisingly large proportion (47% to 80%) of total flow volumes. Different kinds of virtual material flows tended to enhance each other through synergistic effects, and CO2 and nitrogen flows tended to have stronger positive synergetic impacts on the other virtual material flows. Our results suggest that it is important to pay particular attention to such fast-growing material flows, promote cooperation between distant countries, and target countries with the largest flows to achieve global sustainable development goals.