Search

Scientific identification of the early-warning status in relation to cultivated land system security (CLSS) is essential for future food security and sustainable development. It is important to establish the early-warning status of cultivated land as it may signal forthcoming problems and even large-scale environmental catastrophes as an effective means to understand both the current status and future development trends of the CLSS. However, the systematic assessment of the early-warning of status of CLSS has not been previously been conducted at the municipal level, and an in-depth study and discussion of its fundamental driving factors is lacking. Thus, we introduce the biological immunity mechanism by way of analogy and demonstrate the feasibility of its application in the early-warning of CLSS. A novel conceptual early-warning index system is developed and this framework applied to 12 cities in Heilongjiang Province of northeast China using adopting fourteen possible indicators. The spatiotemporal evolution of the early-warning status had been explored over the period 1995–2014 using rescaled range (R/S) analysis. Furthermore, the fundamental factors of the early-warning were explored by establishing a rational panel data model. The results indicate that 1) CLSS early-warning status initially rose and then decreased over the last 20 years. 2) The severe level warning areas are mainly found in the southeast and west of the region, while the secure and relatively secure areas are mainly concentrated in the middle-north and southern areas. 3) The observed patterns indicate that, with the exception of Yichun and Suihua, the early-warning status of the province will develop in the future along the same lines as it did so historically. 4) The results of regression analysis indicate that rational panel data model construction should be verified so as not to produce pseudo-regression and that four main driving factors (natural population growth rate, agricultural waste load per unit area of cultivated land, natural disasters index, and industrial wastewater load per unit area of cultivated land) are significantly positively correlated with the early-warning status; one factor (forest cover) is negatively correlated. Policy-makers need to consider the key factors affecting the early-warning status of cultivated land and its spatiotemporal evolution in different regions to formulate appropriate measures in order to mitigate against future threats. [ABSTRACT FROM AUTHOR]

Despite the southern Cape's great climatic and botanical significance (occupying the transition between the temperate and subtropical circulation systems and forming part of a global biodiversity hotspot), palaeoenvironmental data for this region of southern Africa is limited. This study presents pollen, charcoal and sedimentological data preserved in the Vankervelsvlei wetland, situated in the modern year-round rainfall zone at the ecotone between the Fynbos and Afrotemperate Forest biomes. Combining optically stimulated luminescence and radiocarbon dating techniques, it was possible to establish a chronology for a sediment sequence spanning the last 140,000 years, the longest record yet produced in the region. The data suggest that MIS 5d was relatively warmer (low fynbos pollen percentages and Pentzia -type pollen) than later MIS 5, MIS 4 and most of MIS 3 (∼96–37 ka), which were characterised by decreased temperatures (dominance of ericaceous fynbos). The pollen data indicate a complex response to the change from interglacial to glacial conditions, and suggest an important threshold is crossed in regional ecological dynamics. We postulate that during MIS 5d increased summer rainfall under warmer conditions may have offset increased potential evapotranspiration, allowing for the development of more extensive forests. During its early stages of development Vankervelsvlei was more open (increased aquatics and coarse sediment), trapping more longer-distance pollen ( Podocarpus ). As the mire became more closed, local elements dominated; a succession that is reflected in significant changes in the pollen assemblage, as Podocarpus remains only in trace percentages, but pollen of Canthium and Morella , which occupy nearly identical climatic niches as Podocarpus , increase in abundance. It is suggested that drought stress remains limited during the last glacial period as a result of reduced temperatures, compensating for what may have been a more seasonal winter-dominated rainfall regime, and that changes in the pollen record relate to vegetation succession and the development of the wetland rather than to major changes in moisture availability. Due to the virtual absence of palaeodata from the southern Cape covering MIS 5 to MIS 3, the establishment of this record provides an important contribution to the overall palaeoenvironmental history of the region. [ABSTRACT FROM AUTHOR]

Neogene Langebaanweg (LBW) palaeosol-sediment-sequences at the West Coast of South Africa are well known for their well-preserved rich palaeontological heritage. The palaeosols developed on estuarine/marine/coastal alluvial deposits stacked on each other, ranging in age from the Mid-Miocene to Quaternary. Elemental mobility and redistribution based on major and minor element geochemistry of 11 horizons of the ∼18 m sequences were studied to evaluate the degree of chemical weathering, a major process of soil formation; and to reveal important palaeoenvironments in which the palaeosols developed. Elemental geochemistry was carried out on <2 mm samples by X-ray fluorescence spectrophotometry. The carbonate horizons (Bk and 2Bkmb2) were dominated by CaO (mean wt.% = 32.77), while the other horizons had preponderance of SiO 2 (>50% mean wt.). Two (WI-1 and WI-2) of the four weathering indices applied to evaluate weathering intensity proved unsuitable for use in an alluvial palaeosol-sediment sequences such as LBW. Chemical index of alteration (CIA) and chemical index of weathering (CIW) values were relatively more consistent in distribution pattern across the pedocomplex, but caution should be applied when using them in similar cases. The pedogenic carbonate horizons on average had the lowest values for both CIA and CIW (1.12–2.60) suggesting more advanced weathering. Plots of geochemical ratios (quantifying pedogenic processes) against depth show striking variations among and within the palaeosol and sediment sections. Soil formation was more advanced in the Mid-Miocene and Pliocene than in the Quaternary suggesting a more humid and warmer climate than present. We evaluated selected geochemical climofunctions and conclude that more data are obviously needed for a more robust calibration of the models in Langebaanweg palaeosols. [ABSTRACT FROM AUTHOR]

Palaeosols are common along the coastline of southern South Africa as stacked aeolian dune deposits but have rarely been studied. We selected two late Quaternary palaeosols exposed in a marine cliff-face at Koeberg and coastal barrier dune at Goukamma, South Africa in order to improve our understanding of their pedogenesis and palaeoclimate dynamics. Palaeosol-based proxies explored include: elemental geochemistry by X-ray fluorescence spectrophotometry, δ 13 C and δ 18 O isotopes, micromorphology and clay mineralogy by x-ray diffraction. Selected physico-chemical soil properties were analyzed by routine laboratory procedures. The palaeosols comprise predominantly loamy sand to sandy clay loam textures, have a high pH (>6.5), and very low electrical conductivity (<0.89 mS cm −1 ). SiO 2 and CaO are the most abundant of all the elements in the cambic and calcic horizons respectively. The low levels of Al in the parent materials most likely invalidated the applicability of chemical weathering indices (CIA) to assess weathering intensity. In the case of chemical index of weathering (CIW), the age and sedimentary settings of the palaeosols overruled the possibility for K metasomatism and illitization by metamorphism. The indices WI-1 and W1-2 developed by Darmody et al. (2005) appear more consistent with depth. The palaeo MAT computed from palaeosol carbonate oxygen isotope is 14 and 11 °C for Koeberg and Goukamma respectively, while the maximum MAP obtained from the cambic horizon (Bw) of the Goukamma coastal barrier is 653 mm y −1 . The layering seen in the thin section of the calcic layer at Goukamma indicates deposition, possibly by sedimentary differentiation across a palaeo-slope. Clastic calcite and muscovite mica are the dominant minerals in these palaeosols indicating impeded chemical weathering. Similar to many other parts of the world, the coastlines of South Africa has experienced environmental and climate oscillations in the Quaternary. We conclude that along the southern South Africa coasts, a palaeosol based approach to palaeoenvironmental and palaeoclimate reconstruction in combination with other proxies such as pollen and marine based isotopes can provide insights into the environmental oscillations of the late Quaternary. [ABSTRACT FROM AUTHOR]

Abstract: This paper documents the first Holocene palaeoecological record for the Okavango Delta, northwest Botswana. Sedimentological, stable carbon isotope and palynological data, supported by conventional and AMS radiocarbon assays, are presented from coring sites at Gauxa Lagoon and the Ncamasere and Tamacha valleys along the western margin of the Okavango Panhandle. Earliest Holocene vegetation patterns are not readily distinguished at the three sites, owing to poor pollen preservation conditions. A wet phase or period of enhanced Okavango flooding is tentatively identified around 9000BP on the basis of increased accumulation of organic matter within floodplain sediments. Palynological and sedimentological data, combined with stable carbon isotope analyses, suggest that relatively dry conditions extended from 7000 to 4000BP (punctuated by a wet phase at around 6000BP). This is interpreted as indicating reduced rainfall over the Okavango headwaters in Angola. Conditions from around 4000BP became progressively wetter, initially in response to increased water throughputs via the Okavango system. Wettest conditions occurred from 2300 to 1000BP due to a combination of increased regional rainfall and raised Okavango flood levels. Conditions approach those of the present day after this time. A major shift from grass- to sedge-dominated vegetation communities, apparent at all three sites in the past thousand years, is attributed to anthropogenic disturbance. These changes are subsequently discussed in light of regional continental and marine palaeoenvironmental records, and the implications for the future management of the Okavango River considered. [Copyright &y& Elsevier]

The Western Cape Province of South Africa has a long history of human occupation and utilisation; the impact of colonial settlement (late 17th century onwards) on agriculture has been especially prominent. The Mediterranean-type climate of the Western Cape results in landscapes which are potentially susceptible to land degradation, perhaps even desertification. The Swartland is a gently undulating inland plateau underlain largely by fine-grained and nutrient-rich shales of the pre-Cambrian Malmesbury group. Agriculture is the dominant land use to the extent of wholesale landscape transformation. The area has been subject to significant levels of land degradation in the past, manifesting itself as widespread gully erosion. During the 1940s, the region was described as on the verge of economic collapse due to the severity of soil erosion, but concerted soil conservation and education efforts under the political dispensation of the time appear to have averted that scenario. The region now faces the combined challenges of potentially rapid climate change under a considerably altered socio-economic and political order. Downscaled climate change scenarios facilitate a regional assessment of changes in the parameters affecting soil erosion susceptibility in the Swartland and leads to a consideration of the implications of such scenarios for the continuation of contemporary land use practices. [Copyright &y& Elsevier]

• Land use systems is superior to topography in influencing soil properties. • Sites at the upper hillslope positions depict better soil qualities. • Soil properties content reflect optimal site conditions for productivity in the catchment. • The trend of soil properties is tending towards better qualities. Patterns of soil properties in highland environments remain poorly understood and limited knowledge exists on soil quality with respect to land use systems and topographic configurations. In this study, patterns of 12 surface soil physicochemical properties were assessed over a period of three years with respect to land use systems and toposequence positions in the Rwizi catchment of the Lake Victoria Basin. Four land use systems constituting mulched banana, unmulched banana, grassland and tree plantation, and three toposequence positions stratified as footslope, midslope and summit were considered and three replications were applied resulting in a total of 36 sites for soil properties measurements over a three-year period. Topographic attributes (elevation, slope gradient, slope aspect, and location) were collected at each site and correlated with surface soil properties. With the exception of pH and Ca, surface soil physicochemical properties are revealed to be optimal in the catchment. Greater spatial variation was found with soil chemical properties (8–57%) compared to physical properties (7–19%). Land use system registered significant effects (p < 0.05) for all soil chemical properties, as well as bulk density. Toposequence position is shown to have significant (p < 0.05) effects on soil pH, Soil Organic Matter, available P, N and soil texture. The effect of toposequence position revealed better soil quality along the catenary sequence summit > footslope > midslope. Strong and significant regression coefficients (r2 > 0.6, p < 0.05) for topographic attributes were found with soil pH, available P, K, Ca, Mg and sand. Overall, the land use system effect supersedes toposequence position in accounting for variations in surface soil physicochemical properties. Although environments of the Lake Victoria Basin are subject to intense agricultural activity and are usually assumed to be degraded, surface soil physicochemical properties in this part of the catchment reflect relatively healthy soil quality conditions. [ABSTRACT FROM AUTHOR]

Lakes and lake sediments are significant components of the global carbon (C) cycle, and may store very large amounts of organic matter. Carbon sequestration in lakes is subject to substantial temporal and spatial variation and may be strongly affected by human activities. Here, we report accumulation rates (AR) of organic C (OC), total nitrogen (TN) and total phosphorous (TP), and investigate their responses to anthropogenic impact over the past 150 years by analyzing 62 sediment cores from 11 shallow lakes in the Songnen Plain, northeast China. From the center of each of the lakes, we selected one master core for age determination by 210Pb and 137Cs radioisotopes. The contents of OC, TN, TP, dry bulk density and mass specific magnetic susceptibility were then determined for all cores. The regional OCAR, TNAR and TPAR up-scaling from the multiple cores yielded mean values of 51.63 ± 15.13, 2.50 ± 0.98, and 0.90 ± 0.21 g m−2 yr−1, respectively. Nutrient AR in the studied lakes increased by a factor of approximately 2 × from the middle 19th century to the 1950s, and approximately 5 × after the 1950s. Elemental ratios show that the increase in OCAR is mainly the result of C autogenesis from the growth of aquatic plants stimulated by agricultural intensification, including increased chemical fertilizer application and farmland expansion. Significantly enhanced nutrient burial by these lakes after the 1950s resulted from increased anthropogenic impacts in northeast China. More sustainable agricultural practises, including a decrease in P fertilizer use, would result in a lowering of OCAR, TNAR and TPAR in the future. Image 1 • Accumulation rates of C/N/P were reconstructed through 11 age-dated lake sediments in NE China. • Mean accumulation rates for organic C, total N and total P are ca. 52, 2.5, and 0.9 g m−2 yr−1, respectively. • Nutrient accumulation rates increased ∼2 × from the middle 19th century to the 1950s, and ∼5 × after 1950. • Enhanced nutrient burial in these lakes after the 1950s are due to increased anthropogenic impacts. • More sustainable agricultural practises used during the last years would result in lower accumulation rates of C/N/P. Anthropogenic impacts increased ∼2 × nutrient burial in the Songnen Plain lakes of northeast China from the middle 19th century to the 1950s, and ∼5 × after 1950. [ABSTRACT FROM AUTHOR]

This study investigated the polycyclic aromatic hydrocarbons (PAHs) occurrence, and their impact on the microbial community and PAH-degrading genera and genes in the Knysna Estuary of South Africa. The results reveal that the estuary exhibits low PAH levels (114.1–356.0 ng g−1). Ignavibacteriae and Deferribacteres, as well as Proteobacteria and Bacteroidetes, are keystone phyla. Among measured environmental factors, total organic carbon (TOC), nutrients such as nitrite and nitrate, metals as Al, Cr, Cu, Ni, Pb and Zn, and environmental properties (pH and salinity) are primary contributors to structuring the bacterial community assemblage. The abundance of alpha subunit genes of the PAH-ring hydroxylating dioxygenases (PAH-RHDα) of Gram-negative bacteria lies in the range of (2.0–4.2) × 105 copies g−1, while that of Gram-positive bacteria ranges from 3.0 × 105 to 1.3 × 107 copies g−1. The PAH-degrading bacteria account for up to 0.1% of the bacterial community and respond mainly to nitrate, TOC and salinity, while PAHs at low concentration are not significant influencing factors. PAH degraders such as Xanthomonadales, Pseudomonas , and Mycobacterium , which play a central role in PAH-metabolization coupled with other biogeochemical processes (e.g. iron cycling), may contribute to maintaining a healthy estuarine ecosystem. These results are important for developing appropriate utilization and protection strategies for pristine estuaries worldwide. Image 1 • The potential of PAH degradation of a temperate estuary was evaluated. • Characteristics of microbial communities of a fairly-polluted estuary were shown. • NO x − are the sharpest shaping factors for the bacterial community structure. • Dominant PAH degraders include Vibrio, Marinobacterium and Pseudoalteromonas. • PAH degraders mainly respond to nitrate, total organic carbon and salinity. Nitrate is the most important driver of PAH-degrading genera in a slightly/fairly polluted estuary with specific microbial community and low PAH-biodegrading potential. [ABSTRACT FROM AUTHOR]

Palaeoecological evidence is compared with the existing archaeological record to understand how changing human activity, over the past two millennia, impacted fire regimes and vegetation dynamics in the Drakensberg Mountains, South Africa. Sediment cores from two wetland sites in the Cathedral Peak area of the northern Drakensberg, KwaZulu-Natal are dated using accelerator mass spectrometry to chronologically support biological proxy data. Fossil pollen analysis is used to detect changes in vegetation composition, and macroscopic charcoal to reconstruct changing fire regimes. Charcoal accumulation rates (CHAR) are used as a proxy for burned biomass, and charcoal width-to-length ratio (W/L) as a proxy for dominant fuel type, whether grassy or woody. Results indicate an increase in CHAR, coincident with the appearance of cereal-type grasses (>40 μm) c. 550 cal BP, suggesting a change in fire regimes associated with the arrival of early agropastoralists. A notable decline in charcoal W/L at this time indicates a shift towards a more grassy fuel type. This is consistent with a seasonal shift in the timing of ignitions from high intensity late season lightning fires to low intensity early season anthropogenic fires. The latter are less damaging to woody vegetation explaining an overall shift to a more grassy fuel type. Large scale ecosystem change is evident in the colonial period, including decreased forest pollen taxa such as Podocarpus, which may be linked to colonial period logging. The increased dominance of Pteridium spores documents the invasion trajectory of bracken fern into montane grasslands in the area, which is attributed to ecosystem disturbance in the form of colonial fire suppression. The subalpine wetland clearly documents woody encroachment of the surrounding open grassland landscape during the agropastoral and subsequent colonial periods. By contrast, at the montane wetland site, these trends appear to be overprinted by local forest dynamics and recent deforestation, likely an elevation effect. Palaeoecological evidence demonstrates how changes in fire regimes and vegetation composition in the northern Drakensberg are closely tied to human activity over the past two millennia. [ABSTRACT FROM AUTHOR]

• Understanding of urban green spaces dynamics are required to improve urban sustainability. • Green spaces in the city center of Shanghai shifted from a net loss to net gain from 1980 to 2015. • The shape and distribution of urban green spaces have become more regular and less fragmented. • Population growth and greening policies are major drivers of green spaces change. Urban green spaces play a range of significant roles and have a positive influence on the quality of life in cities. Shanghai, a major economic and financial center in China, has set its goal to become a more ecologically integrated and livable city. The urban authorities envisage Shanghai as "a city in the forest, a forest in the city". To achieve this greener future, the government has developed a series of policies to improve urban greening coverage. Based on land use and land cover data from 1980 to 2015, this paper analyzes temporal and spatial changes in urban green spaces in Shanghai, and explores the driving forces underlying the observed changes. Although the total urban green spaces in Shanghai declined from 1980 to 2015, different districts have different trends. Urban green spaces in the suburbs and the islands have declined, although, the city center increased its green spaces following several decades of decrease. Several factors have contributed to these changes, including population increase, conflicting government policies, real estate development, and rising demand for recreation space. Knowledge of the dynamics of urban green spaces in the city can assist in fostering an appropriate balance between urban development and environmental protection. To prevent environmental degradation and to plan a restoration pathway, cities should attempt to keep green spaces in mind during the development process and integrate the green spaces into urban planning. Understanding the dynamics of green spaces in Shanghai may offer insights for other cities in developing their own green spaces. [ABSTRACT FROM AUTHOR]

The increase in global population has been accompanied by rising consumption of natural resources such as clean air, water and land. Demand for land has increased significantly over the past 30 years or so, both inland and at the coast. In coastal regions, reclaiming land from the sea has often been the preferred solution towards meeting the need for more land for urban development. Seaward land reclamation entails the formation of artificial land surfaces which are constructed in such a way as to extend outwards over the sea using advanced geo-engineering techniques. The process is driven by numerous underlying factors and has manifold impacts. Although this pattern of urban development is not new, the nature, scale and magnitude of land extension has changed dramatically for a range of underlying reasons involving both ‘natural’ geophysical, and anthropogenic factors. The overall aim of this paper is to evaluate the changing spatial extent of seaward land expansion in 16 selected coastal megacities. Remote sensing data, spanning the time period mid-1980's to present, were obtained and used to determine the extent of spatial change due to new land construction in each of the cities. Landsat TM satellite imagery was used to calculate the percentage increase and area reclaimed since the mid-1980s. In addition, a systematic classification is proposed, based on the different geomorphic patterns that have been observed to characterize the process. Among 16 cities analyzed in this study, major land reclamation projects have been especially marked in China, most prominently in Shanghai, which has expanded its coastal area by more than 580 km 2 in the recent past. [ABSTRACT FROM AUTHOR]

The distribution of pollen in marine surface sediments offshore of the west coast of South Africa has been investigated to aid in the interpretation of marine pollen records of onshore vegetation changes. A transect of sediment surface pollen samples retrieved from the Namaqualand mudbelt from just south of the Orange River mouth (29°S) to St Helena Bay (33°S) indicates distinctive pollen spectra reflecting vegetation communities on the adjacent continent. Pollen concentration increases southwards, partly in relation to greater pollen productivity due to higher biomass and density of fynbos vegetation and of sedimentary processes and low pollen concentrations consequent to dilution with silt and clay from the Orange River. The distribution of specific pollen taxa suggests that the Orange River is a major contributor of pollen to the northern mudbelt declining southwards, while the pollen distribution in the central mudbelt is largely attributable to seasonal inputs of pollen from offshore berg winds and local ephemeral Namaqualand rivers. The typical fynbos elements dominate in the southern mudbelt indicating a pollen source mainly in the fynbos vegetation types. These conclusions support a companion analysis of fossil pollen records of two marine sediment cores from the northern and southern mudbelt respectively. This study demonstrates that pollen records from marine sediment cores in the Namaqualand mudbelt have the potential to be a tool to reconstruct palaeovegetation on the adjacent continent. However, to better reconstruct the palaeoclimate of South Africa and fully understand the relations between terrestrial and marine deposits, more marine surface sediments along the western coast of South Africa as well as more terrestrial surface sediments need to be studied. [ABSTRACT FROM AUTHOR]

Abstract: Like many of the world''s subtropical regions, southern Africa is highly sensitive to changes in the earth''s climate system, but a dearth of reliable palaeoenvironmental records means that relatively little is known about how regional environments have been affected over centennial to multi-millennial timescales. To a large extent this sensitivity is a function of the position of these regions at the interface between temperate and tropical circulation systems. The resulting seasonality and irregularity of rainfall have limited the development of suitable archives, such as lakes and wetlands, for the preservation of palaeoenvironmental proxies. This paper reviews and evaluates the value of rock hyrax middens as novel palaeoenvironmental archives in southern Africa. Considered are (1) the contemporary taxonomy, distribution and ecology of hyraxes, (2) the mechanisms of hyrax midden development, their physical and chemical structure, rates of accumulation and age; and (3) the palaeoenvironmental proxies preserved within hyrax middens, including fossil pollen, stable isotopes and biomarkers. The interpretive constraints and opportunities offered by these various midden characteristics are assessed with a view to demonstrating the potential of these deposits, widespread as they are through arid and semi-arid southern Africa, in providing a more detailed and chronologically resolved view of late Quaternary palaeoenvironments across the subcontinent. [Copyright &y& Elsevier]

Abstract: In arid and semi-arid areas such as southern Africa, rock hyrax (Procavia capensis) middens represent an exceptionally valuable source of late Quaternary palaeoenvironmental information. Pollen and stable isotope data derived from two rock hyrax middens extracted from De Rif in the Cederberg Mountains of the southwestern Cape, casts new light on climatic changes that occurred across the Last Glacial–Interglacial Transition (LGIT) and the Holocene (19.5–0.7calkBP) and how the region''s vegetation responded to these changes. Significant changes in vegetation community composition would be expected in response to environmental changes characteristic of the contrast between ‘glacial’ and ‘interglacial’ climates. However, the pollen assemblages in general indicate that mountain fynbos remained dominant throughout the record and that most of the pollen taxa exhibited only muted frequency variations. This finding could be considered to be inconsistent with indications of marked climatic variations recorded in the stable isotope records for the same midden. An analysis of the geological setting and the bioclimatic affinities of the taxa suggest that the explanation for this inconsistency may lie in the dominating influence of sandstone substrates and the relative resilience of mountain fynbos vegetation to climate change. [Copyright &y& Elsevier]

• Ocean Health Index is used to assess the ecosystem health of Shanghai's ocean. • Some parameters and reference points were adjusted to apply OHI at the city scale. • Clean Water and Fisheries scored the lowest and have also been declining. • This research provides experience on applying OHI to other coastal areas. The ocean delivers many ecosystem services to human society in providing food, livelihoods, and recreation and is crucial for regulating the global climate. Coastal cities, which have become the backbone of national economies, are highly dependent on the ecosystem services supported by the ocean. As a global coastal megacity, Shanghai has benefited enormously from its relationship with the ocean but its burgeoning population and rampant economic development in recent decades have applied great pressures on the associated coastal ecosystems and have reduced the ocean's capacity to provide ecosystem services and, meanwhile, have led to the demand for greater investment in ocean ecosystem restoration. To support the goal of long-term sustainability and facilitate appropriate management decisions, it is essential to assess the current health status of the coastal ecosystems of Shanghai and evaluate potential future risks. Here we apply the Ocean Health Index (OHI) framework, with indicators and reference points adjusted based on the unique coastal environment in Shanghai. The results reveal that the city obtained an overall OHI of 59 (out of 100) for the period 2012 to 2016. Individual indicators for Clean Waters (22) and Fisheries (39) exhibit particularly low values, indicating that the coastal waters around Shanghai are heavily polluted and that marine fishing is unsustainable. The city's highest OHI scores are in the sectors of Coastal Livelihoods and Economies (93), and Tourism and Recreation (93), indicating that Shanghai's coastal ecosystems contribute significantly to people's livelihoods and regional economies, while marine recreational areas and related leisure activities add considerably to the quality of life in the region. This study demonstrates the value of the OHI in assessing ocean health at the city scale and reveals its potential for application in other coastal localities. In so doing, the findings provide a valuable benchmark against which to measure progress towards the sustainable development of Shanghai's oceans. [ABSTRACT FROM AUTHOR]

Many coastal cities are short of land for development and, coupled with the need to mitigate the impact of extreme events against a background of ongoing sea-level rise, coastal land reclamation (CLR) has emerged as a frequently applied solution, most especially in Asia. However, the sustainability of these newly reclaimed lands under the combined onslaught of increasing population pressure, SRL, greater frequency of extreme events, and land subsidence is largely unknown. In order to assess the spatial extent and temporal trends in recent CLR projects, we mapped and tabulated the annual magnitude of change in coastal land gain from 1988 to 2018 for eight major Asian coastal cities. Across these cities, both the spatial extent and rate of CLR is remarkable; some 700 km2 has been reclaimed in just three decades. >35% of this new coastal land has been constructed in Shanghai alone (562 km2), while Singapore and Incheon have also experienced substantial land gains. These three cities alone account for almost 10% of all the land gained globally over the last three decades. An analysis of the spatio-temporal patterns reveals that, since recently reclaimed areas are predominantly characterized by construction, including ports, airports, commercial and residential uses, economic development is the most prominent driver. Shanghai, however, represents a significant departure from this trend, whereby >50% of the new coastal land gained during the recent past has not been devoted to construction projects and is vegetated, suggesting a different policy context. Commercial or otherwise, subsidence is widely reported as a major characteristic of recently reclaimed coastal land and is a major environmental challenge. Mapping recent rates of land subsidence over these newly reclaimed lands reveal that most are subject to significant levels of deformation, in the case of the international airport at Incheon, Republic of Korea, exceeding 25 cm annually. Unlabelled Image • Across eight Asian cities, both the spatial extent and rate of reclamation has exceeded 700 km2 since 1988. • More than one third of all new coastal land globally has been constructed in Shanghai alone. • The most prominent driver of coastal land reclamation is economic development. • Newly reclaimed land is subject to marked land subsidence that may exceed 25 cm annually. [ABSTRACT FROM AUTHOR]

[Display omitted] • A detailed model was developed to simulate the energy fluxes of bare roofs and green roofs. • The energy budget difference between the bare and green roofs was quantified. • On a bare roof, approximately 32.25% of the incident solar radiation was absorbed by structures. • Green roofs intercepted and consumed nearly 89% of incident solar radiation. Green roofs, as a nature-based solution, can be an effective tool for cities to improve the thermal environment, save energy, and combat climate change. However, it remains unclear how green roofs change the energy budget of urban building surfaces. Therefore, we modeled the surface energy balance of bare and green roofs based on experimental observations over a full calendar year to compare the physical transport processes of energy flows on bare and green roofs. Observational data were used to quantify the seasonal influence of green and bare roof surfaces on the energy flows and to document how roof vegetation alteres surface energy flow via physical and biochemical processes. On the bare roof, the incident solar radiation was partitioned largely into heating the building structure, with approximately 32.3% of the solar radiation absorbed. The green roof intercepted and consumed nearly 89% of incident solar radiation. The green roof effectively reduced convective energy by 6.7% compared to the bare roof, while longwave radiation emitted by green roof surfaces was reduced by 24.89 Wm−2. Evapotranspiration was the primary form of energy consumption on the green roof, accounting for 23.7% of the energy output. Results show that seasonal green roof evapotranspiration ranks as follows: winter > summer > spring > autumn. Reflected solar radiation, upward longwave radiation, and latent heat flux accounted for almost 95% of the total energy output of the green roof. Quantifying the energy balance impacts of green roofs on urban building surfaces improves the accuracy of urban climate models and supports adopting green roofs to foster sustainable urban development. [ABSTRACT FROM AUTHOR]

Building height is a crucial variable in the study of urban environments, regional climates, and human-environment interactions. However, high-resolution data on building height, especially at the national scale, are limited. Fortunately, high spatial-temporal resolution earth observations, harnessed using a cloud-based platform, offer an opportunity to fill this gap. We describe an approach to estimate 2020 building height for China at 10 m spatial resolution based on all-weather earth observations (radar, optical, and night light images) using the Random Forest (RF) model. Results show that our building height simulation has a strong correlation with real observations at the national scale (RMSE of 6.1 m, MAE = 5.2 m, R = 0.77). The Combinational Shadow Index (CSI) is the most important contributor (15.1%) to building height simulation. Analysis of the distribution of building morphology reveals significant differences in building volume and average building height at the city scale across China. Macau has the tallest buildings (22.3 m) among Chinese cities, while Shanghai has the largest building volume (298.4 108 m3). The strong correlation between modelled building volume and socio-economic parameters indicates the potential application of building height products. The building height map developed in this study with a resolution of 10 m is open access, provides insights into the 3D morphological characteristics of cities and serves as an important contribution to future urban studies in China. • A first country-wide 10 m building height map for China. • Shading index is the most important variable in estimating building height. • High degree of building height accuracy with RMSE of 6.1 m. [ABSTRACT FROM AUTHOR]

Coastal societies are known to be vulnerable to sea-level rise. However, here we report the occurrence of salt manufacturing in the archaeological record of an island of East China that reveals an adaptation strategy by a prehistoric coastal society to sea-level rise through an interdisciplinary study of archaeology and stratigraphy. Archaeological findings and observations of marine microfossils and alkaline earth metals in sediment sequences, together with radiocarbon and optically stimulated luminescence (OSL) dating, reveal that the site was initially occupied at ca. 2900 BCE as an island village with multiple subsistence strategies including hunting, fishing, and stone-tool making associated with the formation of a freshwater dominated coastal plain. Seawater inundation induced by relative sea-level rise occurred at the site at ca. 2400 BCE when Neolithic people constructed elevated mounds and developed specialized sea-salt manufacture in the sheltered tidal flat environment on the island. Evidence from the foraminiferal assemblage suggests that salty soil was scraped from the surface of the adjacent tidal flats and waste material was dumped around the artificial mounds. Micro-structures of the foraminiferal fossils further indicate that these salty soils were air-dried before brine enrichment to produce high-quality salt. Such an economic shift from multiple subsistence into specialized sea-salt manufacture on the island stands in striking contrast to the contemporaneous abandonment of numerous Liangzhu settlements on the adjacent mainland due to coastal flooding. We suggest that prehistoric sea-salt manufacture on the East China coast signifies the resilience of coastal societies in facing the challenge of sea-level rise through exploitation of geographical advantages and marine resources. • Daxie Island was occupied by Neolithic people practicing multiple subsistence at 2900 BCE. • Coastal flooding at 2400 BCE terminated the occupation, although the site was not abandoned. • Sea-salt industry developed associated with the construction of elevated mounds. • The sea-salt making procedure included air-drying and leaching salty soil, and brine-boiling. • Such cultural adaptation prompts a re-assessment of post-Liangzhu archaeology. [ABSTRACT FROM AUTHOR]