Racing climate change: Collaboration and conflict in California's global climate change policy arena

Media accounts routinely refer to California's Assembly Bill 32 (AB 32), the Global Warming Solutions Act of 2006, as “landmark” climate change legislation. On its surface, this label is an accurate reflection of the state's forward-thinking stance across many environmental issues including pesticides, toxic substances, solid waste, and air quality. For all its promise, however, AB 32 can also be considered a low point in the landscape of conflict between state environmental regulators and California's environmental justice movement. While the legislation included several provisions to address the procedural and distributive dimensions of environmental justice, the implementation of AB 32 has been marked by heated conflict. The most intense conflicts over AB 32 revolve around the primacy of market mechanisms such as “cap and trade.” This article examines the drivers and the manifestations of these dynamics of collaboration and conflict between environmental justice advocates and state regulators, and pays particular attention to the scalar and racialized quality of the neoliberal discourse. The contentiousness of climate change politics in California offers scholars and practitioners around the world a cautionary tale of how the best intentions for integrating environmental justice principles into climate change policy do not necessarily translate into implementation and how underlying racialized fractures can upend collaboration between state and social movement actors.     

Influence of the Frasnian-Famennian event on radiolarian faunas

The impact of the Frasnian-Famennian biotic mass extinction event (F-F event) on radiolarian faunas is examined in 13 sections, which belong to two types of cherty basin in South China. No appreciable decrease in radiolarian biodiversity is observed across the F-F boundary. Indeed, radiolarian faunas flourished during the Famennian. The F-F event may not have had any dramatic effect on the radiolarian faunas in deep water and the disappearance of Famennian radiolarians in shallow water platform sections may simply be a result of sea level change rather than any biotic crisis.     

Lithological heterogeneity in a back-barrier sand island: Implications for modelling hydrogeological frameworks

Sediment mineralogy, quartz-grain surface-textures, grain-size analysis, bore-hole logging and ground penetrating radar are combined to develop a three dimensional stratigraphic model of a back-barrier sand island in southeast Queensland, Australia. The island consists of an unconsolidated sedimentary pile above an erosional bounding surface at the top of the underlying bedrock. The stratigraphy is complex, recording the shift in depositional environments from fluvio-deltaic to strandplain, via estuarine stages of evolution. The back-barrier island deposits are correlated with the stratigraphy of the adjacent coastal plain to the west and the barrier island to the east. Extrapolation of optically stimulated luminescence dates obtained from the barrier island combined with direct dating of the back-barrier island sediments is used to constrain the depositional age and chronology of the back-barrier island stratigraphy. The modern depositional environment evolved from a chenier plain into a barrier island system by the flooding of an interdune swale and development of a shore-parallel back-barrier tidal lagoon. The lithological heterogeneity of the back-barrier island succession was controlled by the presence of a bedrock incised palaeovalley and changes in relative sea-level.Sedimentary facies associations constrain the spatial distribution of hydraulic properties controlled by lithological heterogeneity. Post-depositional alteration horizons are integrated with the facies model to account for the effects of weathering and diagenesis on hydraulic behaviour. The derived hydrostratigraphy describes a vertically stacked, dual aquifer, island groundwater system consisting of a semi-confined palaeovalley aquifer overlain by an unconfined strand-plain aquifer.Hydrostratigraphic analysis based on sedimentary facies associations, integrated with post-depositional alteration characteristics reveals great complexity of groundwater systems within small island settings. The facies modelling approach employed in this study more accurately estimates the distribution of lithological heterogeneity and the associated variations in hydraulic properties in the sedimentary pile.     

Temporal river channel changes in the Gila Box Riparian National Conservation Area,Arizona, USA

Human activities have led to the serious decline and degradation of riparian areas in the Southwestern United States. Areas in Arizona, such as the Gila Box Riparian National Conservation Area, are protected to conserve and restore these unique ecosystems. This study investigated temporal change in the channel form and sinuosity of the Gila River in the Gila Box Riparian National Conservation Area. Specifically, cross sections were measured in 1994, 2001, and 2008 to evaluate changes in channel form. Aerial photographs between 1935 and 2007 were also compared to assess changes in channel sinuosity. Based on cross-sectional measurements, the thalweg was significantly deeper in 1994 than in 2001 and 2008, while width-depth ratios were significantly lower in 2008 than in 1994 and 2001. These measurements indicate that the channel is stabilizing. Sinuosity changed only slightly. Overall, climate patterns that cause large flood events appear to have been the major influence on the channel form. Still, exclusion of livestock and all-terrain vehicles, which increased vegetation in the riparian areas, also appeared to mitigate flood impacts. The stream channel appears to have been more resilient to the impacts of the flood in 2005, when vegetation was better established, than to the flood of 1993, when past management influences were still lingering.     

Variable nitrate concentration–discharge relationships in a forested watershed

The relationship between solute concentrations and discharge can inform an integrated understanding of hydrological and biogeochemical processes at watershed scales. Recent work from multiple catchments has shown that there is typically little variation in concentration relative to large variations in discharge. This pattern has been described as chemostatic behavior. Pond Branch, a forested headwater catchment in Maryland, has been monitored for stream nitrate (NO₃^?) concentrations at weekly intervals for 14 years. In the growing season and autumn of 2011 a high‐frequency optical NO₃^? sensor was used to supplement the long‐term weekly data. In this watershed, long‐term weekly data show that NO₃^? concentrations decrease with increasing discharge whereas 6 months of 15‐minute sensor observed concentrations reveal a more chemostatic behavior. High‐frequency NO₃^? concentrations from the sensor collected during different storm events reveal variable concentration–discharge patterns highlighting the importance of high resolution data and ecohydrological drivers in controlling solute export for biologically reactive solutes such as NO₃^?.     

Analytic investigation of climate stability on Titan: sensitivity to volatile inventory

We develop a semiempirical grey radiative model to quantify Titan’s surface temperature as a function of pressure and composition of a nitrogen-methane-hydrogen atmosphere, solar flux and atmospheric haze. We then use this model, together with non-ideal gas-liquid equilibrium theory to investigate the behavior of the coupled surface-atmosphere system on Titan. We find that a volatile-rich Titan is unstable with respect to a runaway greenhouse—small increases in solar luminosity from the present value can lead to massive increases in surface temperature. If methane has been photolyzed throughout Titan’s history, then this runaway can only be avoided if the photolytic ethane is removed from the surface-atmosphere system.     

The role of vegetation and bed-level fluctuations in the process of channel narrowing

A catastrophic flood ire 1965 on Plum Creek, a perennial sandbed stream in the western Great Plains, removed most of the bottomland vegetation and transformed the single-thalweg stream into a wider, braided channel. Following eight years of further widening associated with minor high flows, a process of channel narrowing began in 1973; narrowing continues today. The history of channel narrowing was reconstructed by counting the annual rings of 129 trees and shrubs along a 5-km reach of Plum Creek near Louviers, Colorado. Sixty-three of these plants were excavated in order to determine the age and elevation of the germination point. The reconstructed record of channel change was verified from historical aerial photographs, and then compared to sediment stratigraphy and records of discharge and bed elevation from a streamflow gaging station in the study reach. Channel narrowing at Plum Creel: occurs in two ways. First, during periods of high flow, sand and fine gravel are delivered to the channel, temporarily raising the general bed-level. Subsequently, several years of uninterrupted low flows incise a narrower channel. Second, during years of low flow, vegetation becomes established on the subaerial part of the present channel bed. In both cases, surfaces stabilize as a result of vegetation growth and vertical accretion of sediment.     

一种面向水质监测的地球空间传感器网络架构

地球空间传感器网络将无线传感器网络与地理信息系统、全球定位系统、卫星遥感等技术进行了有效的交叉与融合,但目前仍缺乏统一的体系结构;因此,提出了一种面向水质监测的地球空间传感器网络架构,重点内容是其中数据管理子系统的软件设计与具体实现。考虑到监测数据具有分布式、多源、异构等特点,因而数据管理子系统的设计是基于面向服务的软件体系架构（SOA）,采用富互联网应用（RIA）技术作为主要的软件开发方式,使整个系统具有自动刷新、负载平衡等特点。通过在加拿大安大略省的具体应用,与传统的各种水质监测手段进行对比,该架构具有监测内容更全面、数据显示更直观等优势。     

A model for radial dike emplacement in composite cones based on observations from Summer Coon volcano,Colorado, USA

We mapped the geometry of 13 silicic dikes at Summer Coon, an eroded Oligocene stratovolcano in southern Colorado, to investigate various characteristics of radial dike emplacement in composite volcanoes. Exposed dikes are up to about 7 km in length and have numerous offset segments along their upper peripheries. Surprisingly, most dikes at Summer Coon increase in thickness with distance from the center of the volcano. Magma pressure in a dike is expected to lessen away from the pressurized source region, which would encourage a blade-like dike to decrease in thickness with distance from the center of the volcano. We attribute the observed thickness pattern as evidence of a driving pressure gradient, which is caused by decreasing host rock shear modulus and horizontal stress, both due to decreasing emplacement depths beneath the sloping flanks of the volcano. Based on data from Summer Coon, we propose that radial dikes originate at depth below the summit of a host volcano and follow steeply inclined paths towards the surface. Near the interface between volcanic cone and basement, which may represent a neutral buoyancy surface or stress barrier, magma is transported subhorizontally and radially away from the center of the volcano in blade-like dikes. The dikes thicken with increasing radial distance, and offset segments and fingers form along the upper peripheries of the intrusions. Eruptions may occur anywhere along the length of the dikes, but the erupted volume will generally be greater for dike-fed eruptions far from the center of the host volcano owing to the increase in driving pressure with distance from the source. Observed eruptive volumes, vent locations, and vent-area intrusions from inferred post-glacial dike-fed eruptions at Mount Adams, Washington, USA, support the proposed model. Hazards associated with radial dike emplacement are therefore greater for longer dikes that propagate to the outer flanks of a volcano.