‘It’s more than just what it is’: Defetishising commodities, expanding fields, mobilising change…

Commodity geographies are politically weak. Geographical pedagogy isn’t particularly engaging. Radical geography should make connections. But it rarely leaves room for interpretation. Too much seems to be too didactic. And to preach to the converted. That’s a problem that needs attention. So, is it possible to develop a radical, less didactic, geography? With research funding, publication and teaching the way they are? To engage more students, more heartily, in the issues studied? To promote social justice, critical citizenship, and participatory democracy? But not by setting out the right ways to think, be, or act. Some film-makers, artists and writers have been able to do this. It seems. Subtly and cleverly. Through projects attempting to de-fetishise commodities. But their politics have been placed largely in the background, between the lines of, or separated out from, the presentation of scenes, things, relations, bodies, lives and voices. Seen and unseen elements of their audiences’ lives. Re-connected. Perhaps. Through communication strategies giving audiences something to think about and to think with, to argue about and to argue with. Putting themselves in the picture, in the process. These less didactic materials may be difficult to master for an exam or an essay. They may not make it clear who or what’s right or wrong or what audiences are supposed to do. But they could engage them in less direct ways. When they’re shopping for petrol or fish, or when they’re doing or thinking about completely different things. Things that may not even come under the heading of ‘production’ or ‘consumption’. This approach might be labelled as ‘weak’, ‘relativist’, a bit too ‘cultural’ ‘post-modern’, or ‘defunct’. But it’s an approach that may be radical in effect because its ‘politics’ aren’t so straightforward or ‘up front’. This paper is about changing relationships between research, writing, teaching, learning and assessment; expanding fields of commodity geographies to include classrooms as sites not only of ‘instruction’, but also of learning, for researchers and their students¹; showing how such learning might usefully shape research and writing elsewhere in these fields for those engaged in this defetishising project.     

RURAL POPULATION LOSS AND CROPLAND CHANGE IN THE SOUTHERN PLAINS: IMPLICATIONS FOR CROPLAND RETIREMENT POLICY*

Given steadily increasing federal expenditures to manage surplus crop production, it would seem to make economic and environmental sense to concentrate production on the best acreage and to retire marginal crop acreage to alternate uses. A major obstacle constraining adoption and implementation of cropland retirement programs in the past has been the fear that cropland retirement threatens the viability of rural communities. Regression of change in population and retail establishments on changes in farm structure, nonfarm employment, and agricultural land-use in the rural Southern Plains between 1930 and 1970 provides only weak evidence to support this fear. In fact, short-term cropland idling under post-1960 price-support programs appears to pose more of a threat to rural communities than does cropland retirement.     

Climate, water management, and policy in the San Pedro Basin: results of a survey of Mexican stakeholders near the U.S.–Mexico border

This paper reviews regional climate knowledge and vulnerability in the northern Mexico San Pedro River Basin, with a focus on water quality, quantity, and management issues on the Mexican side of the border. A discussion based on the available literature is supplemented by a survey assessing concerns about water and the quality and usability of climate and hydrologic information available to water managers and communities. The surveys indicate that the central concern for urban residents is the lack of reliable potable water due to frequent service breakdowns–with climate change and variability, specifically drought and high temperatures, as contributing factors. Water managers desire appropriate meteorological and hydrologic information to improve planning strategies, but access to this information remains limited. Considerable disagreement exists about who should pay for previously free or low-cost water and wastewater treatment. Urban users have little incentive to conserve because of the present flat, low rate and frustration with service. In rural areas, while a majority of ranchers recognize that variable climate and water loss could increasingly jeopardize their lifestyle, they seldom use meteorological information in planning or modify their water consumption. Climate vulnerability also includes potential for serious environmental health issues due to the presence of heavy metals and organic contaminants in the San Pedro.     

Landsystem analysis of a tropical moraine-dammed supraglacial lake,Llaca Lake,Cordillera Blanca,Perú

Tropical glaciers of the Cordillera Blanca, Perú are rapidly thinning and retreating as a result of climate warming. The retreat of these glaciers along narrow linear bedrock valleys has increased the number and size of moraine-dammed glacial lakes formed in the valleys. This study aims to identify the geomorphological and sedimentological characteristics of an enlarging moraine-dammed supraglacial lake (Llaca Lake) in the Cordillera Blanca. Field-based sedimentological observations and geomorphological mapping were combined with remotely sensed data and a photogrammetric model derived from aerial surveys by an uncrewed aerial vehicle to identify landform-sediment assemblages. The geomorphological and sedimentological characteristics of Llaca Lake are synthesized into three landsystem zones: Zone 1: distal portions of Llaca Lake and the latero-frontal moraine; Zone 2: the central zone of ice-cored hummocks; and Zone 3: the active glacier margin. These zones are differentiated based on the spatial distribution of landforms, sediments, and active geomorphological processes. This is the first study to describe the landform-sediment assemblages in a tropical moraine-dammed supraglacial lake system and provides a framework for further landsystem element analysis of these growing supraglacial lakes in rapidly deglaciating high-altitude environments.     

Exploring the science of resilience: critical review and bibliometric analysis

Natural Hazards - The concept of resilience has experienced extraordinary development since the 1970s. Resilience is now an integral part of human society and has become a hot topic in different...     

Multi-instrument remote and in situ observations of the Erebus Volcano (Antarctica) lava lake in 2005: A comparison with the Pele lava lake on the jovian moon Io

The stable, persistent, active lava lake at Erebus volcano (Ross Island, Antarctica) provides an excellent thermal target for analysis of spacecraft observations, and for testing new technology. In the austral summer of 2005 visible and infrared observations of the Erebus lava lake were obtained with sensors on three space vehicles Terra (ASTER, MODIS), Aqua (MODIS) and EO-1 (Hyperion, ALI). Contemporaneous ground-based observations were obtained with hand-held infrared cameras. This allowed a quantitative comparison of the thermal data obtained from different instruments, and of the analytical techniques used to analyze the data, both with and without the constraints imposed by ground-truth. From the thermal camera data, in December 2005 the main Erebus lava lake (Ray Lake) had an area of ≈ 820 m². Surface colour temperatures ranged from 575 K to 1090 K, with a broad peak in the distribution from 730 K to 850 K. Total heat loss was estimated at 23.5 MW. The flux density was ≈ 29 kW m^− 2. Mass flux was estimated at 64 to 93 kg s^− 1. The best correlation between thermal emission and emitting area was obtained with ASTER, which has the best combination of spatial resolution and wavelength coverage, especially in the thermal infrared. The high surface temperature of the lava lake means that Hyperion data are for the most part saturated. Uncertainties, introduced by the need to remove incident sunlight cause the thermal emission from the Hyperion data to be a factor of about two greater than that measured by hand-held thermal camera. MODIS also over-estimated thermal output from the lava lake by the same factor of two because it was detecting reflected sunlight from the rest of the pixel area. The measurement of the detailed temperature distribution on the surface of an active terrestrial lava lake will allow testing of thermal emission models used to interpret remote-sensing data of volcanism on Io, where no such ground-truth exists. Although the Erebus lava lake is four orders of magnitude smaller than the lava lake at Pele on Io, the shape of the integrated thermal emission spectra are similar. Thermal emission from this style of effusive volcanism appears to be invariant. Excess thermal emission in most Pele spectra (compared to Erebus) at short wavelengths (< 3 μm) is most likely due to disruption of the surface on the lava lake by escaping volatiles.     

Field Study of Soil Vapor Extraction for Reducing Off-Site Vapor Intrusion

Soil vapor extraction (SVE) is effective for removing volatile organic compound (VOC) mass from the vadose zone and reducing the potential for vapor intrusion (VI) into overlying and surrounding buildings. However, the relationship between residual mass in the subsurface and VI is complex. Through a series of alternating extraction (SVE on) and rebound (SVE off) periods, this field study explored the relationship and aspects of SVE applicable to VI mitigation in a commercial/light-industrial setting. The primary objective was to determine if SVE could provide VI mitigation over a wide area encompassing multiple buildings, city streets, and subsurface utilities and eliminate the need for individual subslab depressurization systems. We determined that SVE effectively mitigates offsite VI by intercepting or diluting contaminant vapors that would otherwise enter buildings through foundation slabs. Data indicate a measurable (5 Pa) influence of SVE on subslab/indoor pressure differential may occur but is not essential for effective VI mitigation. Indoor air quality improvements were evident in buildings 100 to 200 feet away from SVE including those without a measurable reversal of differential pressure across the slab or substantial reductions in subslab VOC concentration. These cases also demonstrated mitigation effects across a four-lane avenue with subsurface utilities. These findings suggest that SVE affects distant VI entry points with little observable impact on differential pressures and without relying on subslab VOC concentration reductions.     

How do Stability Corrections Perform in the Stable Boundary Layer Over Snow?

We assess sensible heat-flux parametrizations in stable conditions over snow surfaces by testing and developing stability correction functions for two alpine and two polar test sites. Five turbulence datasets are analyzed with respect to, (a) the validity of the Monin–Obukhov similarity theory, (b) the model performance of well-established stability corrections, and (c) the development of new univariate and multivariate stability corrections. Using a wide range of stability corrections reveals an overestimation of the turbulent sensible heat flux for high wind speeds and a generally poor performance of all investigated functions for large temperature differences between snow and the atmosphere above (>10 K). Applying the Monin–Obukhov bulk formulation introduces a mean absolute error in the sensible heat flux of \(6\,\hbox {W m}^{-2}\) (compared with heat fluxes calculated directly from eddy covariance). The stability corrections produce an additional error between 1 and \(5\,\hbox {W m}^{-2}\), with the smallest error for published stability corrections found for the Holtslag scheme. We confirm from previous studies that stability corrections need improvements for large temperature differences and wind speeds, where sensible heat fluxes are distinctly overestimated. Under these atmospheric conditions our newly developed stability corrections slightly improve the model performance. However, the differences between stability corrections are typically small when compared to the residual error, which stems from the Monin–Obukhov bulk formulation.     

Development of a vector-based 3D grain entrainment model with application to X-ray computed tomography scanned riverbed sediment

Sediment transport equations typically produce transport rates that are biased by orders of magnitude. A causal component of this inaccuracy is the inability to represent complex grain-scale interactions controlling entrainment. Grain-scale incipient motion has long been modelled using geometric relationships based on simplified particle geometry and two-dimensional (2D) force or moment balances. However, this approach neglects many complexities of real grains, including grain shape, cohesion and the angle of entrainment relative to flow direction. To better represent this complexity, we develop the first vector-based, fully three-dimensional (3D) grain rotation entrainment model that can be used to resolve any entrainment formulation in 3D, and which also includes the effect of matrix cohesion. To apply this model we use X-ray computed tomography to quantify the 3D structure of water-worked river grains. We compare our 3D model results with those derived from application of a 2D entrainment model. We find that the 2D approach produces estimates of dimensionless critical shear stress ( ) that are an order of magnitude lower than our 3D model. We demonstrate that it is more appropriate to use the c-axis when calculating 2D projections, which increases values of to more closely match our 3D estimates. The 3D model reveals that the main controls on critical shear stress in our samples are projection of grains, cohesive effects from a fine-grained matrix, and bearing angle for the plane of rotation (the lateral angle of departure from downstream flow that, in part, defines the grain's direction of pivot about an axis formed by two contact points in 3D). The structural precision of our 3D model demonstrates sources of geometric error inherent in 2D models. By improving flow properties to better replicate local hydraulics in our 3D model, entrainment modelling of scanned riverbed grains has the potential for benchmarking 2D model enhancements. © 2019 The Authors. Earth Surface Processes and Landforms Published by John Wiley & Sons Ltd.     

Everyday Encounters with Activist Scholarship

In light of the grave challenges ahead under the Trump administration and the rise of right-wing populism in the West, it is critical that geographers across subdisciplines embrace activist and engaged scholarship. Opportunities for such engagement often emerge organically in our everyday lives at the intersection between personal interests, ethics and commitments, and nascent research agendas. In this article, I share two experiences with community-engaged and activist research: (1) establishing the Los Puentes Spanish–English dual-language immersion program in partnership with a low-income rural North Carolina public school system and (2) collaborating on the Building Austin, Building Injustice participatory action research project with a community-based workers center to document and lobby for improvements to construction workers’ conditions in Austin, Texas. Through a situated and positioned personal account, I seek to not only provide two examples of activist research but also illustrate the diversity of encounters and how they can emerge in unlikely places and outside conventional “activist” arenas. In conclusion, I draw on lessons learned through these experiences to reflect on the various challenges and opportunities for activist scholarship within geography in the future.