How does student behavior respond to extreme temperatures and who is most affected? Using daily student-level data from a large urban school district, I estimate the causal effect of temperature on two dimensions of student behavior that are predictive of academic and later life outcomes: school absences and disciplinary referrals. Absenteeism increases in response to both hot and cold conditions, particularly for Black and Hispanic students. Hot conditions also increase the likelihood that a student will receive a disciplinary referral, an effect found only among students attending schools without air conditioning. Results suggest that unequal access to air conditioning may exacerbate racial, ethnic, and socioeconomic disparities in school.

The D4 RIN is the tradable compliance certificate for the biomass-based diesel (BBD) mandate in the renewable fuel standard (RFS). Understanding the price dynamics of the D4 RIN is important for understanding the RFS because its price sets a ceiling on the ethanol RIN (D6) and because some observers have suggested that RIN price fluctuations are too large to be explained by economic theory. We use option pricing theory to develop a model of the D4 RIN in terms of its economic fundamentals: the spread between the price of biodiesel and petroleum diesel and the status of the biodiesel blenders’ tax credit. The resulting D4 fundamental price closely tracks actual D4 prices. We conclude that RIN price volatility arises because of the design of the RFS and intrinsic features of the U.S. fuel supply system.

Between 2005 and 2015, US electricity sector emissions of nitrogen oxides and sulfur dioxide, which harm human health and the environment, declined by two thirds, and many coal-fired power plants became unprofitable and retired. Intense public controversy has focused on these changes, but the literature has not identified their underlying causes. Using a new electricity sector model of the US eastern interconnection that accurately reproduces unit operation, emissions, and retirement, we find that electricity consumption and natural gas prices account for nearly all the coal plant profitability declines and resulting retirements. Environmental regulations had little effect on these outcomes.

While the initial distribution of emissions allowances is usually thought to be independent of the emissions outcome, free allocation can affect the efficiency and fairness of allowance trading. Inefficiency may result from thin allowance markets, poor price discovery, and regulatory or organizational complexities that hinder the recognition of opportunity costs. Concerns about fairness may result from intransparency in the process of transferring substantial allowance value. We explore the role of consignment auctions in mitigating these concerns. These revenue-neutral auctions return the financial value of allowances to their original holders while revealing prices and directing allowances to their highest-valued use. They also can be used to support a minimum price when allowances are freely distributed, which may facilitate program linkage. Consignment auctions have minimal administrative costs and do not necessarily involve government. Experience indicates that they can play an important role, especially in new markets.

The Clean Power Plan (CPP) is expected to play an important role in reducing U.S. greenhouse gas emissions. In February 2016, responding to appeals from some of the affected industries and states, the U.S. Supreme Court issued a stay suspending implementation of the CPP until after the judicial review process. Industry groups stated the CPP will pose large and "irreparable" costs to the coal sector during the period of judicial review. However, modeling suggests that because of prevailing market, technological, and policy trends, the CPP will result in near-zero costs beyond current trends until 2025, in part because of the plan's built-in flexibility. These factors and lessons from option theory suggest the stay is economically unjustifiable based on claims of irreparable economic harm to the coal sector. If implementation of the rule proceeds, current trends imply the stay will have little effect on industry's ability to follow the current compliance schedule.

Understanding and acting on the link between weather and meningitis in the Sahel could help improve vaccine distribution and save lives. People living there know that meningitis epidemics occur in the dry season and end after the start of the rainy season. Integrating and analyzing newly available epidemiological and meteorological data quantified this relationship, showing that that the risk of meningitis epidemics climbed from a background level of 2% to a maximum risk of 25% during the dry season. These data also suggested that, of all meteorological variables, relative humidity has the strongest correlation to cases of meningitis.

Weather acts alongside a complex set of environmental, social, and economic drivers, and a complementary investigation of local and regional knowledge, attitudes, and practices suggested several additional interventions to manage meningitis. These include improved awareness of early meningitis symptoms and vaccinations for farmworkers who migrate seasonally. An economic survey showed that the cost of a single case of meningitis is 3 times the average annual household income, underscoring the need for improved vaccination strategy.

Using these insights, meteorologists and public health workers developed a tool to guide vaccination decisions. Iterative development allowed a multinational team of public health officials to use the tool while guiding its refinement and directed research toward maximum practical use. That meant focusing on predicting areas where high humidity would naturally end epidemics so vaccines could be moved elsewhere. Using this tool and this approach could have prevented an estimated 24,000 cases of meningitis over a 3-yr period.