The port city of Beira, on Mozambique’s Indian Ocean coast, was devastated by Tropical Cyclone Idai in March 2019. Ever since, a host of unequal international and national actors have been wrangling ...about the best forms to ‘build back better’, with uneven and socially and spatially unequally distributed results. The institutional set-up and concomitant challenges of making adaptation work are described in a context where the pressures of both growth-based development and climate change mitigation are particularly manifest. In particular, the tensions are explored between political and economic imperatives and the seemingly apolitical, technical best practices advanced by Mozambique’s bi- and multilateral donor partners, as well as the complex infrastructural and economic interdependencies that condition urban planning and development. Through this, the very real constraints of transitioning to climate-resilient cities are demonstrated, along with how most of what turns a climate event into a human disaster sits within highly unequal social, political and economic systems. Policy relevance Empirical, ethnographic material gathered from the post-cyclone reconstruction process in Beira, Mozambique, shows how institutional complexities and political rivalry limit the possibilities of reconstruction. These organisational issues impact more than technical or financial challenges. ‘Best practices’ of ‘building back better’ are almost rendered moot by socio-economic and political constraints, revealing the substantial challenges of implementing large-scale, technically ‘best practice’ reconstruction programmes. The analysis of the factors that contributed to making Cyclone Idai such a calamitous event holds important lessons for climate adaptation and disaster reconstruction in coastal cities, especially for those operating in challenging political and economic conditions.
The world is rapidly suburbanising and, as recognised in numerous academic and policy documents, suburbs are not only environmentally unsustainable but also particularly vulnerable to climate change. ...This same literature and policy discourse suggests the solution to making suburbs more sustainable and adaptable is densification and investing in infrastructural green growth. Meanwhile, alternative approaches in critical suburban literature suggest that densification might create negative externalities, and instead propose the transformation of infrastructures’ management and ownership to support an innovative and autochthonous path for suburbs’ climate adaptation. Yet limited empirical knowledge exists on what adaptation strategies are being implemented across peripheral municipalities where suburbs are more prevalent. A comparative analysis is presented of three peripheral municipalities in Santiago de Compostela, Spain, on their adaptation strategies for water and sanitation. This shows how mainstream assumptions about suburbs and imaginaries of adaptation influence their strategies, as well as how the specific characteristics in the peripheral municipalities allow or hamper more innovative approaches. Three factors emerge as more important in allowing innovation and autochthonous solutions: the level of suburbanisation, the management model for municipal infrastructures, and their political context (including proximity of local government with higher-tier bodies and government composition). Practice relevance Peripheral municipalities around the world, with a predominant suburban character, are considered the most unsustainable form of urbanisation and the areas in cities that are most at risk to climate change. This research demonstrates the importance of policymakers’ imaginaries for advancing less formal and de facto (as well as formal) innovative adaptation strategies in peripheral municipalities. While the production of formal adaptation strategies by capital cities’ governments is growing, less formal, more intuitive and de facto strategies dominate any adaptation efforts in peripheral municipalities, where suburbs are prevalent. Opportunities for innovation in adaptation strategies and challenging existing assumptions reside in influencing the underlying policy assumptions and imaginaries that peripheral municipalities’ policymakers currently hold.
Rapid urbanization has resulted in the permanent conversion of large areas of cropland and natural vegetation to impervious surfaces and therefore greatly modified land surface properties and ...land‐atmosphere interactions. This study sought to examine the urbanization process using Landsat images from 2001 to 2010 in metropolitan JingjinTang (JJT), a rapidly expanding urban cluster in northern China. We aggregated the original results of land use data as fractional cover information in 1 km and 10 km grids. Annual and seasonal land surface temperatures (LSTs) were processed from Moderate Resolution Imaging Spectroradiometer products. We used moving window and gradient analysis methods to examine the differences in LST between urban and other land types, further identifying LST increases in gradients of urbanization levels. Urban extent increased by 1.6 times, and approximately 45% newly developed areas were converted from croplands during this process. Emerging urban land in JJT has caused approximately 0.85 ± 0.68°C warming in terms of annual mean LST, and the greatest warming occurred in the summer. An increase in urban land of 10% in a 1 km grid in JJT would cause approximately a 0.21°C increase in annual LST. Urbanization also led to increases in daytime LSTs and nighttime LSTs by approximately 1.03 ± 1.38°C and 0.78 ± 1.02°C, respectively. The warming trend induced by urbanization exhibits clear seasonal and diurnal differences, and this warming trend is most likely caused by the cumulative effects of changes in land properties, radiation storage, and anthropogenic heat release by urbanization.
Key Points
Local warming on LST by urbanization
Linear relationship between warming magnitude and urban fractions increase
Seasonal and diurnal variation of local warming on LST
The present study evaluates the ambient particulate matter (PM2.5) and associated elemental concentrations during the festival of Diwali (firecrackers bursting amid religious celebrations) during ...October–November in India. PM2.5 on Diwali day was 182 μg/m3, which is three times more than National Ambient Air Quality Standard (NAAQS) set by the government of India with metals contributing 22.7% to the PM2.5 load on 24 October 2022. Barium, potassium, strontium, aluminum and magnesium are major elements found in PM2.5. Multiple correlation and enrichment factor also gave similar results. Arsenic concentration exceeds the NAAQS along with cadmium (European Commission) and lead (USEPA) exceeds permissible standards during Diwali days. It is concluded that the bursting of fireworks during the Diwali celebration is a significant contributor to gaseous, and metal pollution, which includes hazardous elements like arsenic, cadmium, and lead. Although the population exposed to the pollution was at risk for a few days, significant health impacts can result from unfavourable weather conditions, as is typically seen in north India during the months of October through November. In general, low-quality conventional firecrackers can pose detrimental health impacts to children and older people during low planet boundary conditions with minimal wind velocity.
•Metal bound PM2.5 contributes 22.7% to the total fine particulate matter load on Diwali day.•Arsenic, cadmium and lead concentration in ambient air exceeded permissible standards during Diwali.•Significant positive correlation (p-value<0.001) among Al, Ba, K, Mg and Sr, a typical signature of firecrackers found in this study.•Enrichment factor gave highly significant change in barium and strontium during Diwali days as compared to non-Diwali days.
This study employs an evaluated Surface Urban Energy and Water Balance Scheme (SUEWS) model driven by Local Climate Zone (LCZ)-derived urban canopy parameters to explore landscape heterogeneity's ...impacts on the partitioning of surface energy fluxes and heat stress variations in Lagos, Nigeria. The results reveal that LCZ-based SUEWS effectively replicates the diurnal patterns of air temperature (Tair), relative humidity (RH), and land surface temperature (LST). The root mean square error (RMSE) for simulated Tair and RH ranges from 0.4 °C to 1.2 °C and 1.8% to 8.0%, respectively. While a nighttime warm bias in LST is observed, it reduces during the daytime. Significant spatial variability in turbulent heat fluxes and LST among LCZs is noted, with core urban LCZs experiencing notable increases in sensible heat flux and LST, while suburban LCZs exhibit higher latent heat flux values. Anthropogenic heat flux peaks in high compact low-rise LCZ 3, reaching a maximum of 95 W/m2. Remarkably, no significant difference is found in the diurnal heat stress cycle among LCZs, despite consistently elevated heat stress levels in high compact LCZs. These findings offer valuable insights into quantifying surface energy flux variabilities and spatio-temporal heat stress patterns in a densely populated tropical city- Lagos Nigeria.
•SUEWS simulated high-res weather variables in a tropical high-dense city.•Urban land cover significantly affects surface energy fluxes.•Compact, dense LCZs exhibit higher turbulent heat fluxes and LST.•Anthropogenic heat flux estimated at 23 W/m2, with peaks up to 95 W/m2.
The study of human biometeorological conditions is becoming increasingly important in climate perception for the improvement of public health system. The present study investigates the long-term ...thermal bioclimate conditions in four stations of West Bengal, India. Kolkata, the capital city of West Bengal, and three suburban stations, namely, Dum Dum, Canning and Diamond Harbour
,
located in the adjacent districts of Kolkata
,
have been selected. The biometeorological conditions have been estimated by physiological effective temperature (PET) and modified physiologically equivalent temperature (mPET) at 1130 h and 1730 h (IST) based on 42 years of meteorological data. The initial purpose of this study is to present the monthly distribution of PET and mPET categories and further highlight the structure of each thermal index in four tropical climate locations. The results from this analysis reveal higher human thermal stress in Kolkata compared to other neighbouring stations during the period from 1979 to 2018. Reverse behaviour was observed from 2018 to 2020 indicating that Diamond Harbour and Canning are warmer in terms of human thermal stress compared to Kolkata and Dum Dum. The results captured has also been validated by mean monthly, mean seasonal PET and mPET index difference between Kolkata (urban station) and other three stations (suburban areas). During the past period (1979–2018), highest differences in PET and mPET were recorded in Canning and Diamond Harbour for the months September to November (SON), varying between 4 and 5 °C both at prenoon and evening. The second highest differences of indices ranging from 2.5 to 3.5 °C were observed during December to February (DJF). For the last two years (2018–2020), the seasonal differences of PET and mPET are negative, implying that Dum Dum, Canning and Diamond Harbour at 1130 h are warmer by a maximum of 2 °C in comparison to Kolkata. Finally, the mean annual thermal indices of each year show a growing trend in all the four stations with a variation of 0.4°C to 0.7°C and 1.1°C to 1.3°C in early noon and evening measurements respectively for 40 years.
This study analysed the variations of relative humidity (RH) over the past 60 years in Shenzhen—an emerging megacity located in the Pearl River Delta region of China. The analysis revealed three ...stages of mean annual RH in Shenzhen since 1961: (1) a stable period with little change from 1961 to 1980; (2) a fluctuating downward trend from 1981 to 2008, with a linear transformation of −2.5%/decade, explained by a decrease in water-retention capacity in the underlying surface caused by the rapid expansion of the urban and built-up land area in Shenzhen; and (3) a fluctuating, rapid upward trend since 2009, with a linear transformation of 5.2%/decade. The rising RH after 2008 was related to policies of the Shenzhen government that were commenced in 2004, aimed at improving the city's ecological environment. The policies included increasing vegetation cover and improving environmental quality coinciding with the gradual expansion of the urban and built-up areas. The resulting increase in water-retention in the underlying surface produced the gradual increase in RH. The data concerning variations in RH and their causes in Shenzhen show that the orderly expansion of urban and built-up land areas, and ecological environmental improvements can be achieved concurrently in densely populated cities, allowing elements of the local climate to return to their natural state to some extent.
•The humidity in Shenzhen has decreased since 1980 and then increased since 2008.•The increase of NDVI is why the humidity has increased.•Urban eco-environmental policies are the key reason to the increase of NDVI.
Solar reflective “cool pavements” have been proposed as a potential heat mitigation strategy for cities. However, previous research has not systematically investigated the extent to which cool ...pavements could reduce urban temperatures. In this study we investigated the climate impacts of widespread deployment of cool pavements in California cities. Using the Weather Research and Forecasting model, we simulated the current climate of California at 4 km spatial resolution. Comparing this simulation to 105 weather stations in California suggested an overall mean bias (model minus observation) of −0.30°C. Widespread pavement albedo increases of 0.1 and 0.4 in California cities were then simulated. Comparing temperature reductions for each scenario showed that the climate response to pavement albedo modification was nearly linear. Temperature reductions at 14:00 local standard time were found to be 0.32°C per 0.1 increase in grid cell average albedo. Temperature reductions were found to peak in the late morning and evening when (a) boundary layer heights were low and (b) solar irradiance (late morning) and heat accumulation in the pavement (evening) was high. Temperature reductions in summer were found to exceed those in winter, as expected. After scaling the results using realistic data‐derived urban canyon morphologies and an off‐line urban canyon albedo model, annual average surface air temperature reductions from increasing pavement albedo by 0.4 ranged from 0.18°C (Palm Springs) to 0.86°C (San Jose). The variation among cities was due to differences in baseline climate, size of the city, urban fraction, and urban morphology.
Key Points
Investigated the impacts of adopting solar reflective cool pavements on the climate of California cities using a meteorological model
City‐mean reductions in temperature from increasing pavement albedo by 0.4 ranged from 0.18°C (Palm Springs) to 0.86°C (San Jose)
The effect of urban canyon morphology on cool pavement impacts was assessed using an off‐line urban canyon albedo model
The impact of the increasing technomass (TM) on cooling demand in buildings is explored for cities in South America. The entangled double nature of the building-environment interrelation in an urban ...context is analyzed. The research question is whether an increase in the building density produces a superlinear increase of energy consumption at the urban scale. Advanced spatially explicit quantitative methods are used to select representative samples of the urban environment and to quantify the volumes of TM in four South American cities. Principal component analysis is used to extract representative urban tissue categories. The Urban Weather Generator tool is used to produce the urban weather data used in building performance simulations. The results confirm the superlinear dependence of the total cooling consumption of each sample in relation to the existing TM in areas with high-rise buildings due to the combined primary and secondary effects, namely, the increase of the total energy needs and the increase of air temperature due to the urban heat island effect. The great significance of the second-order effect poses challenges to current assessments performed on the basis of consumption per m
2
. The use of the TM indicator can promote the development of climate-sensible urban planning.
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