In the first study to use a fully-coupled Earth system model to look at the future climatic effects of trans-Arctic shipping, we find that clouds formed in response to shipping emissions may offset ~1°C of the overall warming trend in the Arctic by the end of the century.

Although there are many options for reducing energy-related CO₂ emissions, some energy services entail emissions that are much more difficult to eliminate. We review technological opportunities and barriers for eliminating and/or managing difficult-to-decarbonize services, and critical areas for further research, development, demonstration and deployment.

China's emissions decreased between 2013-2016. Our analysis shows the decline was largely due to changes in industrial structure and a decline in the share of coal for energy production. Decreases may persist if nascent industrial and energy system transitions continue.

We present new, city-level estimates of CO₂ emissions for 182 Chinese cities, decomposed into 17 different fossil fuels, 46 socioeconomic sectors, and 7 industrial processes, and examine three scenarios of technological progress to show that large reductions (up to 31%) are possible by updating a disproportionately small fraction of existing infrastructure.

"South-South" trade among developing countries is increasing, and helping to reduce China’s emissions by shifting energy-intensive production to less developed regions. But this may make climate mitigation more challenging; emissions are spread among more and less-developed countries.