How to increase diversity in the police is an unanswered question that has received significant political and media attention. One area of intervention is the recruitment process itself. This study reports the results of a randomized controlled trial (RCT) in a police force that was experiencing a disproportionate drop in minority applicants during one particular test. Drawing on insights from the literatures on stereotype threat, belonging uncertainty and values affirmation exercises, we redesigned the wording on the email inviting applicants to participate in the test. The results show a 50 per cent increase in the probability of passing the test for minority applicants in the treatment group, with no effect on white applicants. Therefore, the intervention closed the racial gap in the pass rate without lowering the recruitment standard or changing the assessment questions.

The clean energy transition requires a co-evolution of innovation, investment, and deployment strategies for emerging energy storage technologies. A deeply decarbonized energy system research platform needs materials science advances in battery technology to overcome the intermittency challenges of wind and solar electricity. Simultaneously, policies designed to build market growth and innovation in battery storage may complement cost reductions across a suite of clean energy technologies. Further integration of R&D and deployment of new storage technologies paves a clear route toward cost-eective low-carbon electricity. Here we analyse deployment and innovation using a two-factor model that integrates the value of investment in materials innovation and technology deployment over time from an empirical dataset covering battery storage technology. Complementary advances in battery storage are of utmost importance to decarbonization alongside improvements in renewable electricity sources. We find and chart a viable path to dispatchable US$1 W−1 solar with US$100 kWh−1 battery storage that enables combinations of solar, wind, and storage to compete directly with fossil-based electricity options.

With dramatic cost declines and performance improvements, both mini-hydropower and solar photovoltaics (PV) now serve as core options to meet the growing demand for electricity in underserved regions worldwide. We compare the net energy return on energy invested (EROI) of mini-hydropower and solar electricity using five existing mini-hydropower installations in northern Thailand with grid-connected solar PV simulations. Both assessments use a life cycle perspective to estimate the EROI. We find that distributed mini-grids with penetrations of solar PV up to 50% of annual generation can exceed the EROI of some fossil-based traditional centralized grid systems. The analysis will help planners and engineers optimize mini-grids for energy payback and utilize local resources in their design. The results suggest higher EROI ratios for mini-hydropower plants than solar PV, though mini-hydropower plants typically yield lower EROI ratios than their large-scale hydropower counterparts.

This paper presents the first detailed long-term stock turnover model to investigate scenarios to decarbonize the residential water heating sector in California, which is currently dominated by natural gas. We model a mix of water heating (WH) technologies including conventional and on-demand (tank-less) natural gas heating, electric resistance, existing electric heat pumps, advanced heat pumps with low global warming refrigerants and solar thermal water heaters. Technically feasible policy scenarios are developed by considering combinations of WH technologies with efficiency gains within each technology, lowering global warming potential of refrigerants and decreasing grid carbon intensity. We then evaluate energy demand, emissions and equipment replacement costs of the pathways. We develop multiple scenarios by which the annual greenhouse gas emissions from residential water heaters in California can be reduced by over 80% from 1990 levels resulting in an annual savings of over 10 Million Metric Tons by 2050. The overall cost of transition will depend on future cost reductions in heat pump and solar thermal water heating equipment, energy costs, and hot water consumption.

The Article reviews the United States’ recent decision to withdraw from the Paris Accord and recounts some of the most prominent policy discussions surrounding this decision. The Article goes on to explain, that these policy discussions reject science in favor of short-term political gains. The Article reviews new scientific reports which indicates that sea level rise may be far worse than expected, due in large part to the fact that previous computer models never looked beyond the year 2100. As this Article highlights, our policy discussions have become so heavily focused on the near future that we have created a distorted perception of time that doesn’t mesh with reality. This Article urges policy-makers to take real action on climate now, before it is too late. 

Estimates of climate change damage are central to the design of climate policies. Here, we develop a flexible architecture for computing damages that integrates climate science, econometric analyses, and process models. We use this approach to construct spatially explicit, probabilistic, and empirically derived estimates of economic damage in the United States from climate change. The combined value of market and nonmarket damage across analyzed sectors—agriculture, crime, coastal storms, energy, human mortality, and labor—increases quadratically in global mean temperature, costing roughly 1.2% of gross domestic product per +1°C on average. Importantly, risk is distributed unequally across locations, generating a large transfer of value northward and westward that increases economic inequality. By the late 21st century, the poorest third of counties are projected to experience damages between 2 and 20% of county income (90% chance) under business-as-usual emissions (Representative Concentration Pathway 8.5).

Christiana Figueres and colleagues set out a six-point plan for turning the tide of the world’s carbon dioxide by 2020. Three years to safeguard our climate

Moving beyond a focus on solar roofs for single-family homes, ambitious projects are attempting to join blocks of buildings into sustainable units