Articles

All the world's nuclear-armed states (except for North Korea) have begun modernizing and upgrading their arsenals, leading many observers to predict that the world is entering a new nuclear arms race. While that outcome is not yet inevitable, it is likely, and if it happens, the new nuclear arms race will be different and more dangerous than the one we remember. More nuclear-armed countries in total, and three competing great powers rather than two, will make the competition more complex. Meanwhile, new non-nuclear weapon technologies — such as ballistic missile defense, anti-satellite weapons, and precision-strike missile technology — will make nuclear deterrence relationships that were once somewhat stable less so.

Both energy production and consumption can simultaneously affect regional air quality, local water stress and the global climate. Identifying the air quality–carbon–water interactions due to both energy sources and end-uses is important for capturing potential co-benefits while avoiding unintended consequences when designing sustainable energy transition pathways. The authors examine the air quality–carbon–water interdependencies of China's six major natural gas sources and three end-use gas-for-coal substitution strategies in 2020.

The changing carbon content of coal consumed in China between 2002 and 2012 is quantified using information from the power sector. The carbon content decreased by 7.7% over this interval, the decrease particularly pronounced between 2007 and 2009. Inferences with respect to the changing carbon content of coal and the oxidation rate for its consumption, combined with the recent information on coal use in China, are employed to evaluate the trend in emissions of CO2. Emissions are estimated to have increased by 158% between 2002 and 2012, from 3.9 Gt y-1 to 9.2 Gt y-1.

Solar photovoltaic (PV) electricity generation can greatly reduce both air pollutant and greenhouse gas emissions compared to fossil fuel electricity generation. The Chinese government plans to greatly scale up solar PV installation between now and 2030. However, different PV development pathways will influence the range of air quality and climate benefits. Benefits depend on how much electricity generated from PV is integrated into power grids and the type of power plant displaced. Using a coal-intensive power sector projection as the base case, the authors estimate the climate, air quality, and related human health benefits of various 2030 PV deployment scenarios.

Electrification with decarbonized electricity is a central strategy for carbon mitigation. End-use electrification can also reduce air pollutant emissions from the demand sectors, which brings public health co-benefits. In this article, the authors focus on electrification strategies for China, a country committed to both reducing air pollution and peaking carbon emissions before 2030. Considering both coal-intensive and decarbonized power system scenarios for 2030, they assess the air quality, health, and climate co-benefits of various end-use electrification scenarios for the vehicle and residential sectors relative to a non-electrified coal-intensive business-as-usual scenario.

In the cyber arena, the same technologies that are creating unprecedented benefits for billions are also democratizing destruction. Graham Allison reviews ‘The Virtual Weapon and International Order’ by Lucas Kello.

Electric drive vehicles are equipped with totally different propulsion systems compared with conventional vehicles, for which the energy consumption and cradle-to-gate greenhouse gas emissions associated with vehicle production could substantially change. In this study, the life cycle energy consumption and greenhouse gas emissions of vehicle production are compared between battery electric and internal combustion engine vehicles in China's context.