Investigating the Uncertainties in the Simple Mass Balance Equation for Acidity Critical Loads for Terrestrial Ecosystems in the United Kingdom

The Simple Mass Balance (SMB)equation has been developed and used as one ofthe principal methods for calculating criticalloads of acidity for forest ecosystems. Criticalloads have formed the basis for informing policyrelated to the control and abatement of emissionsof acidifying pollutants. The SMB equationrelies on a variety of assumptions and dataderived from a variety of sources. Each of thesecomponent constituents has a potential source oferror depending on the method(s) used for theirderivation and the value(s) assigned. The resultis the possibility of generating a range ofcritical load values for a single ecosystem. This paper summarises the SMB equation, examinesthe uncertainties in deriving input values andreviews other works on the key assumptions.     

Illinois State Water Survey Bulletin 75: New Precipitation Frequency Study for Illinois

Storm frequency estimates and their temporal distributions are important in determining estimates of runoff or peak flow rates in many engineering and hydrological problems. Illinois State Water Survey Bulletin 70 has been serving as the design rainfall standard in Illinois since its publication in 1989. Although Bulletin 70 represented the best available data at the time of its publication, the standards needed to be reevaluated and updated after more than three decades and with the growing evidence of the nonstationary nature of heavy precipitation. The trends in heavy precipitation in Illinois prompted the creation of a new frequency study named Bulletin 75, providing precipitation frequencies for event durations ranging from 5 min to 10 days and for recurrence intervals ranging from 2 months to 500 years. The results are presented for the same 10 geographic sections in Illinois as in Bulletin 70 to maintain the continuity of hydrologic studies and compatibility with regulations. The primary goal of this paper is to outline some of the key methodological issues and challenges, to compare the results with the previous sources, and to highlight the effects of the changing precipitation standards on the development of amendments to existing ordinances. Lake County in Illinois, as one of the most affected urban areas with the highest change in heavy precipitation, was selected to illustrate issues related to the application of modified precipitation standards.     

Water supply,waste assimilation,and low-flow issues facing the Southeast Piedmont Interstate-85 urban archipelago

Rapidly growing cities along the Interstate-85 corridor from Atlanta, GA, to Raleigh, NC, rely on small rivers for water supply and waste assimilation. These rivers share commonalities including water supply stress during droughts, seasonally low flows for wastewater dilution, increasing drought and precipitation extremes, downstream eutrophication issues, and high regional aquatic diversity. Further challenges include rapid growth; sprawl that exacerbates water quality and infrastructure issues; water infrastructure that spans numerous counties and municipalities; and large numbers of septic systems. Holistic multi-jurisdiction cooperative water resource planning along with policy and infrastructure modifications is necessary to adapt to population growth and climate. We propose six actions to improve water infrastructure resilience: increase water-use efficiency by municipal, industrial, agricultural, and thermoelectric power sectors; adopt indirect potable reuse or closed loop systems; allow for water sharing during droughts but regulate inter-basin transfers to protect aquatic ecosystems; increase nutrient recovery and reduce discharges of carbon and nutrients in effluents; employ green infrastructure and better stormwater management to reduce nonpoint pollutant loadings and mitigate urban heat island effects; and apply the CRIDA framework to incorporate climate and hydrologic uncertainty into water planning.     

Programs assessing implementation and effectiveness of state forest practice rules and BMPs in the West

The major forest nonpoint source control programs in the West are largely regulatory, either under forest practices acts (California, Idaho, New Mexico, Nevada, Oregon, and Washington) or a streamside management act (Montana). These programs and the specific rules they enforce continue to undergo intensive scrutiny. Still, the questions are the same for these regulatory programs as for states that base nonpoint source control on voluntary BMPs (Arizona, Colorado, Utah, Wyoming). Are the rules or BMPs being applied, and are they effective in reducing nonpoint source pollution to levels that protect beneficial uses of water? The level of debate about forestry in the West has resulted in detailed monitoring and research to answer these questions. In the past, state agencies have assumed levels of BMP compliance based on the percent of operations without enforcement actions. These estimates are being replaced by statistically valid and reproducible monitoring of forest practices rules and BMP compliance levels. BMP effectiveness is being assessed using both qualitative and quantitative methods. This can involve field assessments, process-based research, and control watershed studies. Some trend monitoring is also beginning. With the regional implementation rate for forestry BMPs at about 94% and rising, it is likely that effectiveness testing will continue to be a priority and consume the majority of assessment resources for this region.     

Humanitarian aid and local power structures: lessons from Haiti's ‘shadow disaster’

This paper investigates the confluence of humanitarian aid, centralisation, and politics. The 7.0 magnitude earthquake in Haiti on 12 January 2010 led to more than USD 16 billion in pledges. By contrast, Hurricane Matthew, which made landfall in Haiti on 4 October 2016, stayed in the shadows, attracting about one per cent of the amount. While the earthquake exhibited one face of centralisation, the Category 4 storm laid bare rural vulnerabilities shaped by postcolonial state neglect, and reinforced by the influx of non-governmental organisations in the ‘Republic of Port-au-Prince’. The study draws on data from four case studies in two departments to illuminate the legacies of hyper-centralisation in Haiti. Compounding matters, Matthew struck in the middle of an extended election that the international community attempted to control again. The paper argues that disaster assistance and politics are uncomfortably close, while reflecting on the momentary decentralisation of aid after the hurricane and its effectiveness.     

Threats to biodiversity from cumulative human impacts in one of North America's last wildlife frontiers

Land‐use change is the largest proximate threat to biodiversity yet remains one of the most complex to manage. In British Columbia (BC), where large mammals roam extensive tracts of intact habitat, continued land‐use development is of global concern. Extant mammal diversity in BC is unrivalled in North America owing, in part, to its unique position at the intersection of alpine, boreal, and temperate biomes. Despite high conservation values, understanding of cumulative ecological impacts from human development is limited. Using cumulative‐effects‐assessment (CEA) methods, we assessed the current human footprint over 16 regional ecosystems and 7 large mammal species. Using historical and current range estimates of the mammals, we investigated impacts of human land use on species’ persistence. For ecosystems, we found that bunchgrass, coastal Douglas fir, and ponderosa pine have been subjected to over 50% land‐use conversion, and over 85% of their spatial extent has undergone either direct or estimated indirect impacts. Of the mammals we considered, wolves were the least affected by land conversion, yet all species had reduced ranges compared with historical estimates. We found evidence of a hard trade‐off between development and conservation, most clearly for mammals with large distributions and ecosystems with high levels of conversion. Rather than serve as a platform to monitor species decline, we strongly advocate these data be used to inform land‐use planning and to assess current conservation efforts. More generally, CEAs offer a robust tool to inform wildlife and habitat conservation at scale.     

Characteristics of rear-end crashes involving passenger vehicles with automatic emergency braking

Abstract

Objectives: Automatic emergency braking (AEB) is a proven effective countermeasure for preventing front-to-rear crashes, but it has not yet fully lived up to its estimated potential. This study identified the types of rear-end crashes in which striking vehicles with AEB are overrepresented to determine whether the system is more effective in some situations than in others, so that additional opportunities for increasing AEB effectiveness might be explored.

Methods: Rear-end crash involvements were extracted from 23?U.S. states during 2009–2016 for striking passenger vehicles with and without AEB among models where the system was optional. Logistic regression was used to examine the odds that rear-end crashes with various characteristics involved a striking vehicle with AEB, controlling for driver and vehicle features.

Results: Striking vehicles were significantly more likely to have AEB in crashes where the striking vehicle was turning relative to when it was moving straight (odds ratio [OR]?=?2.35; 95% confidence interval [CI], 1.76, 3.13); when the struck vehicle was turning (OR = 1.66; 95% CI, 1.25, 2.21) or changing lanes (OR = 2.05; 95% CI, 1.13, 3.72) relative to when it was slowing or stopped; when the struck vehicle was not a passenger vehicle or was a special use vehicle relative to a car (OR = 1.61; 95% CI, 1.01, 2.55); on snowy or icy roads relative to dry roads (OR = 1.83; 95% CI, 1.16, 2.86); or on roads with speed limits of 70+ mph relative to those with 40 to 45?mph speed limits (OR = 1.49; 95% CI, 1.10, 2.03). Overall, 25.3% of crashes where the striking vehicle had AEB had at least one of these overrepresented characteristics, compared with 15.9% of strikes by vehicles without AEB.

Conclusions: The typical rear-end crash occurs when 2 passenger vehicles are proceeding in line, on a dry road, and at lower speeds. Because atypical crash circumstances are overrepresented among rear-end crashes by striking vehicles with AEB, it appears that the system is doing a better job of preventing the more typical crash scenario. Consumer information testing programs of AEB use a test configuration that models the typical rear-end crash type. Testing programs promoting good AEB performance in crash circumstances where vehicles with AEB are overrepresented could guide future development of AEB systems that perform well in these additional rear-end collision scenarios.     

Fossil fuel divestment in US higher education: student-led organising for climate justice

Based on over one year of participant observation within the student-led fossil fuel divestment (FFD) movement, this article contextualises the origins, successes, challenges, and inner workings of the FFD movement in US higher education. We analyse several college divestment campaigns to illuminate key factors that have contributed to wins and rejections, and explore why students continue to organise for FFD. It is our contention that such widespread mobilisation for FFD signals a sea change, from individualised sustainability efforts to youth-led collective political action, and recognition of climate change as a social justice issue. In addition to participant observation, we gathered data from 23 survey responses of organisers involved in divestment campaigns within higher education, and 40 interviews with individuals including student and professional organisers within the FFD movement, institutional decision-makers at campuses with FFD campaigns, and other experts in the area. Our analysis also reveals that relatively smaller endowments and, more importantly, institutional values of environmental sustainability and social justice played key roles in colleges’ decision to divest. Our examination of divestment “losses” illuminates common arguments administrators deploy in their rejection statements, including the perceived costs of divestment, the need to maintain fiduciary responsibility, and scepticism that divestment will have any impact on the fossil fuel industry. Finally, in spite of increasing resistance from college and university administrations, student divestment campaigns continue to escalate, and are committed to organising over the long term.