Nature-based solutions have moved rapidly up the policy agenda over the past decade. Defined broadly as actions that protect, sustainably manage, or restore natural or modified ecosystems while simultaneously delivering human well-being and biodiversity benefits, they encompass everything from urban forests and rain gardens to wetland restoration and catchment protection. Most of the scientific evidence behind these approaches, however, comes from temperate, humid cities in Europe and North America. Researchers have repeatedly warned that this evidence base cannot simply be transplanted to drylands, where water is the dominant constraint on ecological function and where green infrastructure that works in Berlin or Portland may fail, or even backfire, in Windhoek.

The new research addresses this gap by systematically assembling evidence and insights on dryland nature-based solutions in the specific context of semi-arid Windhoek. The study frames the city as a critical test case: it is a national capital with substantial technical capacity and a long institutional memory of water crisis management, yet it operates under hydrological conditions that stress every assumption of conventional green urbanism. By focusing the analysis on what is actually known, rather than what is assumed, the authors aim to give planners and policymakers a realistic account of where nature-based approaches can deliver climate adaptation benefits and where their limits lie.

The technical logic of the assessment rests on the water balance. In a semi-arid city, every hectare of vegetation consumes water through evapotranspiration, and every liter allocated to greening is a liter not available for households, industry, or the treated wastewater on which Windhoek heavily depends. This means that the desirability of any nature-based intervention depends on its water source and its return on that investment. Interventions that harvest rainwater, infiltrate stormwater into soils, or make use of treated effluent can be water-positive; interventions that rely on potable supplies to maintain ornamental greenery can erode the very resilience they are meant to build. The study situates dryland nature-based solutions squarely within this accounting framework, treating water sourcing as the first-order design question rather than an afterthought.

Windhoek’s own history supplies much of the empirical texture. The city has endured repeated droughts, including the severe regional drought of 2019 that forced drastic supply cuts and left reservoirs at historic lows. Its response arsenal has included some of the world’s most advanced engineered systems: since the late 1960s, Windhoek has practiced direct potable reuse of treated municipal wastewater, and its integrated water demand management has kept per-capita consumption far below that of many comparable cities. Yet these achievements are engineered rather than ecological, and the new study asks whether the city’s green assets, its river corridors, urban trees, open savanna remnants, and informal green spaces, have been integrated into adaptation planning with the same rigor as its pipes and reclamation plants.

A central thread of the analysis is the distinction between different functional classes of nature-based solutions and their suitability to dryland conditions. Vegetated drainage lines and rehabilitated seasonal river channels, for instance, can slow and infiltrate episodic storm flows, reducing flood damage during intense summer storms while recharging soils and shallow groundwater. Xeriscaping and the use of drought-adapted indigenous species can deliver shade, cooling, and amenity at a fraction of the water cost of exotic turf and temperate ornamentals. Protecting remnant thornveld and rocky hillside habitats within the urban fabric can sustain biodiversity and cultural values without ongoing irrigation. Each of these options reflects the study’s core insight that in drylands, nature-based solutions succeed when they are designed to work with scarcity rather than against it.

The cooling question receives particular attention, because urban heat is among the most direct climate threats to dryland cities. Windhoek already experiences hot summers, and climate projections for central Namibia indicate more frequent and intense heat extremes, which bear hardest on low-income neighborhoods with limited access to shade and cooling. Trees and vegetated areas cool their surroundings through shade and evapotranspiration, but in a semi-arid context the cooling benefit must be weighed against the water consumed. The evidence assembled in the study points toward targeted, water-efficient greening, priority shade trees along pedestrian routes, canopy in schools and clinics, and greenery irrigated with treated effluent, as the configurations most likely to deliver heat protection without compromising water security.

Governance emerges as a second major theme. The study emphasizes that nature-based solutions are not merely planting projects; they are long-term institutional commitments that require land tenure clarity, maintenance budgets, cross-departmental coordination, and community stewardship. In Windhoek, as in many Southern African cities, the urban landscape is deeply unequal, with leafy former suburbs adjoining dense informal settlements where green space is scarce and heat exposure is high. The study argues that climate adaptation through nature-based approaches will be judged not only by hectares greened or liters saved, but by whether the benefits reach the households most exposed to drought, heat, and flood risk. Community-based management, aligned with existing municipal programs, is identified as a practical pathway for sustaining interventions in contexts where municipal maintenance capacity is stretched.

Equally important is the study’s treatment of evidence quality itself. The authors stress that much of the global literature on urban nature-based solutions reports outcomes from mesic environments, and that dryland-specific monitoring data, on infiltration rates, water use, survival of planted vegetation, thermal performance, and social benefits, remain thin, particularly for African cities. Windhoek’s long records of hydrology, water demand, and urban development offer an unusually rich foundation for closing this gap, and the study positions the city as a living laboratory in which carefully monitored pilots could generate the quantitative evidence that dryland urban planners elsewhere currently lack. The recommendation is not to wait for perfect data, but to embed measurement into every intervention from the outset, so that each rain garden, rehabilitated channel, and shade corridor doubles as a research site.

The broader significance of the work extends well beyond Namibia. Hundreds of millions of people now live in dryland cities, from the Sahel to the Middle East to the American Southwest, and that population is growing faster than the global average even as climate change intensifies aridity. For these cities, the Windhoek case suggests that nature-based solutions must be reframed: less about lush greenery and more about strategic, water-aware deployment of dryland ecosystems to buffer floods, heat, and livelihood shocks. The study’s message to the international research and policy community is that semi-arid African cities are not peripheral test beds for ideas developed elsewhere, but front-line innovators whose constraints are producing insights the rest of a drying world will increasingly need. In Windhoek, the future of urban climate adaptation is being written with very little water, and that, the authors argue, is precisely what makes it worth watching.

Subject of Research: Dryland nature-based solutions for climate adaptation in semi-arid Windhoek, Namibia

Article Title: Evidence and insights on dryland nature-based solutions for climate adaptation in semi-arid Windhoek, Namibia

Article References: Evidence and insights on dryland nature-based solutions for climate adaptation in semi-arid Windhoek, Namibia. (n.d.). https://doi.org/10.1038/s42949-026-00468-0

Image Credits: AI Generated

DOI: 10.1038/s42949-026-00468-0

Keywords: nature-based solutions, drylands, climate adaptation, Windhoek, Namibia, semi-arid cities, urban sustainability, water security, urban heat, urban greening, water demand management, drought resilience

The scale of transformation in Ahmedabad is striking. Multi-decadal analyses of land use and land cover report that the city’s built-up area expanded by more than 130 percent between 1990 and 2019, largely at the expense of farmland, peri-urban vegetation, and open ground. Long-term assessments stretching back to 1976 confirm a pattern of continuous peripheral growth, in which rural and semi-urban zones have been progressively absorbed into the metropolitan fabric. What was once a compact historic core has evolved into an increasingly dispersed and heterogeneous urban system, pushed outward in every direction beyond the Sabarmati River by industrial corridors, major road networks, and large-scale residential development. Manufacturing hubs, commercial centers, and institutional zones have accelerated land conversion across the vast peri-urban belt surrounding the city.

Jaipur’s story is different in shape but similar in substance. Studies of the Rajasthan capital document significant and steady growth in built-up land since the mid-1990s, consumed mainly at the cost of agricultural land, scrubland, and open spaces. Unlike Ahmedabad’s radial spread, Jaipur’s expansion has been strongly directional, concentrated in the western, southern, and northwestern sectors of the city. The review attributes this asymmetry to the development of major roads, industrial estates, institutional nodes, and large residential colonies in those directions, combined with the availability of flat, easily developable land and improving connectivity. Vegetation cover in Jaipur has shown a consistent declining trend across the periods reported in the literature. Although planned green areas such as parks and landscaped localities have increased slightly, these gains are confined to small geographic pockets and do not compensate for the loss of natural and agricultural cover, with negative consequences for the city’s ecological balance.

The thermal consequences of these land conversions are well documented in both cities. Satellite-based studies consistently find a positive correlation between the growth of built-up area and rising land surface temperature, or LST, across multiple temporal scales. The mechanism is straightforward physics. When permeable, vegetated ground is replaced with impervious materials such as concrete and asphalt, the surface absorbs more solar radiation and retains more heat. Urban surfaces typically have lower albedo than natural vegetation, meaning they reflect less sunlight and absorb more energy. At the same time, the loss of vegetation and open land reduces evapotranspiration, the process by which plants release moisture and cool their surroundings. Dense building clusters, narrow streets, and high-rise construction further obstruct airflow and natural ventilation, trapping heat within street canyons and degrading the city’s capacity to shed warmth after dark.

The review distinguishes carefully between related thermal phenomena. The urban heat island, or UHI, describes the situation in which air temperatures in an urban center exceed those of surrounding rural areas because of urbanization, vegetation loss, and waste heat from human activity. The surface urban heat island, or SUHI, is its surface manifestation, measured through satellite-derived estimates of land surface temperature rather than thermometer readings. In Ahmedabad, the interplay between these phenomena proves surprisingly complex. Surface moisture availability and the agricultural cropping cycle strongly influence SUHI intensity. During the pre-monsoon season, when soils are dry and vegetation cover is sparse, rural areas around the city can become extremely hot, sometimes producing lower or even negative daytime SUHI intensity, meaning the city surface is not dramatically hotter than its parched surroundings. Nighttime SUHI intensity, however, remains consistently positive, because urban materials store heat during the day and release it slowly after sunset. Jaipur, by contrast, shows an almost constant rise in land surface temperature driven by the steady expansion of urban surfaces.

Methodologically, the two cities have followed markedly different research trajectories, and this asymmetry is one of the review’s central findings. Ahmedabad has emerged as a methodological benchmark for predictive urban growth modeling in India. Its studies routinely integrate cellular automata–Markov chain models, artificial neural networks, transition probability matrices, and validation statistics such as kappa coefficients, weaving in population data, road proximity, and industrial growth indicators to simulate future expansion scenarios. This modeling sophistication gives planners a genuine capacity to evaluate alternative futures. Jaipur’s literature, in contrast, remains largely retrospective, relying on conventional supervised classification and change detection to document what has already happened, with few predictive modeling studies. Both cities exhibit comparable trends of vegetation loss and rising surface temperature, but the strength of evidence available to support forward-looking urban planning is considerably greater for Ahmedabad.

The review itself was conducted with unusual rigor for a narrative synthesis. The author searched Scopus, Web of Science, Google Scholar, and ScienceDirect from June to December 2025, using combinations of keywords covering land use and land cover, urban and surface heat islands, land surface temperature, remote sensing and GIS, urban growth modeling, and World Heritage City urbanization. The initial search returned 90 articles, which were screened down to 51 full texts and finally to 39 studies included in the qualitative comparative analysis, following a PRISMA-inspired framework to ensure transparency and reproducibility. Because the underlying studies used different satellite sensors, spatial resolutions, classification algorithms, and validation procedures, the review deliberately avoided direct numerical comparison, instead synthesizing evidence across common themes including growth pattern, thermal response, modeling sophistication, and planning relevance.

The stakes extend well beyond thermal maps. Rising urban temperatures elevate the risk of heat illness, dehydration, respiratory disease, and cardiovascular stress, with outdoor laborers, elderly residents, and economically disadvantaged communities facing the greatest exposure. Heat stress is also linked to declining labor productivity in construction, transport, and informal work sectors that dominate rapidly growing semi-arid cities. Climate change compounds these pressures by intensifying heatwaves and droughts and by reducing water availability, while vegetation loss, shrinking water bodies, and groundwater depletion erode urban ecological resilience. Recent Ahmedabad studies have begun integrating land surface temperature, evapotranspiration, vegetation indices, and groundwater parameters into compound analyses of urban growth and climate variation, though comparable integrated research in Jaipur remains scarce. For cities whose historic urban fabric, from Jaipur’s planned eighteenth-century grid to Ahmedabad’s walled old city, is the very asset that earned global recognition, unmanaged heat and sprawl threaten both environmental sustainability and heritage conservation.

The review identifies clear research gaps and a path forward. Most existing work concentrates on biophysical change detected through remote sensing, while socioeconomic, institutional, and governance drivers, including census-based demographics, migration, and land-use policy, remain underexplored in both cities. Peri-urban transition zones, where land conversion is fastest and least controlled, deserve far more detailed spatial assessment. The author calls for integrating land change analysis with urban climate modeling, heat stress mapping, and land-atmosphere interaction studies, and for greater use of machine learning techniques such as random forest, support vector machines, deep learning, and hybrid cellular automata approaches. Heat vulnerability analysis, combining thermal exposure with population density, public health indicators, and access to green space, is flagged as essential for identifying at-risk communities. On the policy side, the prescriptions are concrete: expand green infrastructure, protect urban ventilation corridors, promote permeable surfaces and nature-based solutions, and embed heritage-sensitive climate adaptation into planning. As the review concludes, the future sustainability of India’s semi-arid World Heritage Cities depends on treating land use, urban climate, and cultural heritage as a single, inseparable planning problem rather than three separate bureaucracies.

Subject of Research: Land use transformation and urban heat island dynamics in the UNESCO World Heritage Cities of Jaipur and Ahmedabad, India

Article Title: Land use transformation and urban heat dynamics in India’s world heritage cities Jaipur and Ahmedabad

Article References: Land use transformation and urban heat dynamics in India’s world heritage cities Jaipur and Ahmedabad. (n.d.). https://doi.org/10.1007/s44327-026-00361-6

Image Credits: AI Generated

DOI: 10.1007/s44327-026-00361-6

Keywords: land use land cover, urban heat island, land surface temperature, Jaipur, Ahmedabad, remote sensing, GIS, urbanization, World Heritage Cities, CA-Markov, surface urban heat island, semi-arid cities