Department of Geography

In this special issue, we have tried to bridge studies of the Chinese state and of the Chinese city by employing the concepts of space production and territoriality. Three sets of analytical tools frame our questions: First, we use the concept of “urbanization of the local state” instead of “state-led urbanization” to capture the active role of urban processes as a formative force in social transformation and a definitive element in the making of the local state. Urban construction has become the key mechanism of local state building in the areas of public finance, territorial power consolidation, and local leaders’ political performance. Second, we expand the concept of the city to encompass the notion of territoriality, defined as spatial strategies to consolidate power in a given place and time and to secure autonomy. Territorial contestation is unusually intense when the premises of state authority are under-defined and local state jurisdictional boundaries shift frequently, as has been the case in China over the past thirty years. Third, we expand the analysis of territoriality from the realm of the state to that of society with the concept of “civic territoriality.” This concept refers to societal actors’ conscious cultivation and struggle to build territory for self protection and autonomy at the physical, socio-political, and discursive levels. Civic territoriality is central to societal actors’ cultivation of collective identities, to their framing of grievances and demands, and to their options and choice of collective actions. This framework helped to organize the seven contributions of this issue into the following three themes: Territorial Order and State Power, Territorialization of Capital, and Civic Territoriality.   Download PDF for full text of Introduction.

Future climate presents conflicting implications for forest biomass. We evaluate how plant hydraulic traits, elevated CO₂ levels, warming, and changes in precipitation affect forest primary productivity, evapotranspiration, and the risk of hydraulic failure. We used a dynamic vegetation model with plant hydrodynamics (FATES-HYDRO) to simulate the stand-level responses to future climate changes in a wet tropical forest in Barro Colorado Island, Panama. We calibrated the model by selecting plant trait assemblages that performed well against observations. These assemblages were run with temperature and precipitation changes for two greenhouse gas emission scenarios (2086-2100: SSP2-45, SSP5-85) and two CO₂ levels (contemporary, anticipated). The risk of hydraulic failure is projected to increase from a contemporary rate of 5.7% to 10.1-11.3% under future climate scenarios, and, crucially, elevated CO₂ provided only slight amelioration. By contrast, elevated CO₂ mitigated GPP reductions. We attribute a greater variation in hydraulic failure risk to trait assemblages than to either CO₂ or climate. Our results project forests with both faster growth (through productivity increases) and higher mortality rates (through increasing rates of hydraulic failure) in the neo-tropics accompanied by certain trait plant assemblages becoming nonviable.

Methyl bromide (CH3Br) is an important ozone-depleting substance whose use is regulated under the Montreal Protocol. Quantifying emissions on the national scale is required to assess compliance with the Montreal Protocol and thereby ensure the timely recovery of the ozone layer. However, the spatial-temporal patterns of Chinas national CH3Br emissions remain unclear. Here we estimate the national emissions of CH3Br in China during 2011-2020 using atmospheric observations at 10 sites across China combined with an inversion technique (top-down) and compare those with an updated inventory of identified emission sources (bottom-up). Measured CH3Br mole fractions are enhanced well above the background mole fractions, especially at sites in eastern China. Top-down emission estimates exceed bottom-up estimates by 5.5 ± 1.4 gigagrams per year, with the largest fraction (60%) of observationally derived CH3Br emissions arising from underestimated or unidentified emissions sources. This study shows the potential impacts of the unaccounted emissions on stratospheric ozone depletion, with implications for the Montreal Protocol.

Extreme rainfall events drive the amount and spatial distribution of rainfall in the Amazon and are a key driver of forest dynamics across the basin. This study investigates how the 3-hourly predictions in the High Resolution Model Intercomparison Project (HighResMIP, a component of the recent Coupled Model Intercomparison Project, CMIP6) represent extreme rainfall events at annual, seasonal, and sub-daily time scales. TRMM 3B42 (Tropical Rainfall Measuring Mission) 3 h data were used as observations. Our results showed that eleven out of seventeen HighResMIP models showed the observed association between rainfall and number of extreme events at the annual and seasonal scales. Two models captured the spatial pattern of number of extreme events at the seasonal and annual scales better (higher correlation) than the other models. None of the models captured the sub-daily timing of extreme rainfall, though some reproduced daily totals. Our results suggest that higher model resolution is a crucial factor for capturing extreme rainfall events in the Amazon, but it might not be the sole factor. Improving the representation of Amazon extreme rainfall events in HighResMIP models can help reduce model rainfall biases and uncertainties and enable more reliable assessments of the water cycle and forest dynamics in the Amazon.

Understanding forest water limitation during droughts within a warming climate is essential for accurate predictions of forest-climate interactions. In hyperdiverse ecosystems like the Amazon forest, the mechanisms shaping hysteresis patterns in transpiration relative to environmental factors are not well understood. From this perspective, we investigated these dynamics by conducting in situ leaf-level measurements throughout and after the 2015 El Niño-Southern Oscillation (ENSO) drought. Our findings indicate a substantial increase in the hysteresis area (Harea) among transpiration (E), vapor pressure deficit (VPD), and stomatal conductance (gs) at canopy level during the ENSO peak, attributed to both temporal lag and differences in magnitude between gs and VPD peaks. Specifically, the canopy species Pouteria anomala exhibited an increased Harea, due to earlier maximum gs rates leading to a greater temporal lag with VPD compared to the post-drought period. Additionally, leaf water potential (ΨL) and canopy temperature (Tcanopy) showed larger Harea during the ENSO peak compared to post-drought conditions across all studied species, suggesting that stomatal closure, particularly during the afternoon, acts to minimize water loss and may explain the counterclockwise hysteresis observed between ΨL and Tcanopy. The pronounced Harea during the drought points to a potential imbalance between water supply and demand, underlining the role of stomatal behavior of isohydric species in response to drought.

Abstract: The Mundra Port on the Gulf of Kutch in western India is one of India's largest port projects today. This article takes the port-circulated narrative of the coast being a natural harbor as its starting point, to show how fresh water was central to official maritime projects until the early postcolonial period. Conserving mangroves and freshwater creeks was not antithetical to maritime ports but part of the same administrative project. Political and infrastructural shifts from the river to the tide naturalized the erasure of coastal fresh water and transformed the coast into a singularly tidal space, creating the conditions for the development of a large-scale, high-technology shipping port.

Care is a practice and form of labour making human survival and flourishing possible. This Symposium explores the place and work of care within housing movements, asking how care operates as a politics, an ethics, and a set of practices through which tenants survive—and ultimately seek to transform—the structural violence of capitalist housing systems. Situated in US cities with abiding associations with Blackness and indigeneity, papers in the Symposium examine housing movements that take care as the starting point. As we discuss in this introduction to the Symposium, in such movements, care operates as connective tissue across households and modes of difference; challenges relations of racial capitalism and settler colonialism that underlie dominant understandings of who deserves and can demand care; and drives calls for public care and experiments with non-propertised forms of ownership. Housing systems are care infrastructures, making housing movements a vital place for care work.

Californian hydroclimate is strongly seasonal and prone to severe water shortages. Recent changes in climate trends have induced shifts in seasonality, thus exacerbating droughts, wildfires, and adverse water shortage effects on the environment and economy. Previous studies have examined the timing of the seasonal cycle shifts mainly as temperature driven earlier onset of the spring season. In this paper, we address quantitative changes in the onset, amounts, and termination of the precipitation season over the past 6 decades, as well as the large-scale atmospheric circulation underpinning the seasonal cycle changes. We discover that the onset of the rainy season has been progressively delayed since the 1960s, and as a result the precipitation season has become shorter and sharper in California. The progressively later onset of the rainy season is shown to be related to the summer circulation pattern extending into autumn across the North Pacific, in particular, a delay in the strengthening of the Aleutian Low and later southward displacement of the North Pacific westerlies.

The geography of the Southeast Asian Islands (SEAI) has changed over the last 15 million years, as a result of tectonic processes contributing to both increased land area and high topography. The presence of the additional land area has been postulated to enhance convective rainfall, facilitating both increased silicate weathering and the development of the modern-day Walker circulation. Using an Earth System Model in conjunction with a climate-silicate weathering model, we argue instead for a significant role of SEAI topography for both effects. SEAI topography increases orographic rainfall over land, through intercepting moist Asian-Australian monsoon winds and enhancing land-sea breezes. Large-scale atmospheric uplift over the SEAI region increases by ∼14% as a consequence of increased rainfall over the SEAI and enhancement through dynamical ocean-atmosphere feedback. The atmospheric zonal overturning circulation over the Indo-Pacific increases modestly arising from dynamical ocean-atmosphere feedback, more strongly over the tropical Indian Ocean. On the other hand, the effect of the SEAI topography on global silicate weathering is substantial, resulting in a ∼109 ppm reduction in equilibrium pCO2 and decrease in global mean temperature by ∼1.7ºC. The chemical weathering increase comes from both enhanced physical erosion rates and increased rainfall due to the presence of SEAI topography. The lowering of pCO2 by SEAI topography also enhances the Indo-Pacific atmospheric zonal overturning circulation. Our results support a significant role for the progressive emergence of SEAI topography in global cooling over the last several million years.