Ielts 2026 Reading Question 36

Section A Urban areas concentrate population, infrastructure and economic activity, but they also concentrate environmental risks. Climate change and intensifying urbanisation have amplified heat, flooding and air pollution in cities, creating acute public-health and infrastructure challenges. Green infrastructure - the network of natural and semi-natural features such as trees, parks, green roofs, wetlands and permeable surfaces - is increasingly promoted as a cost-effective way to bolster urban climate resilience. Unlike single-purpose grey infrastructure, green infrastructure simultaneously provides multiple ecosystem services: cooling through shading and evapotranspiration, stormwater attenuation, carbon sequestration, and habitat for urban biodiversity. These services can reduce vulnerability to extreme heat and heavy rainfall, but their performance varies by context, design and maintenance regimes. Assessing the cost-benefit profile of green infrastructure requires considering both direct and indirect benefits: reduced energy consumption, avoided grey infrastructure upgrades, improved public health and enhanced property values. Quantifying these co-benefits remains methodologically challenging but essential for investment decisions. Section B Mechanisms by which green infrastructure influences urban microclimates are well understood. Trees create shade and lower near-surface air temperatures, while evaporation from leaves (evapotranspiration) dissipates heat. Green roofs and walls add insulation to built structures, reducing energy demand for cooling and moderating roof-surface temperatures. Permeable pavements and vegetated swales increase infiltration and delay runoff, reducing peak flows during storms. Urban wetlands, ponds and engineered rain gardens provide temporary water storage and support cooling through evaporation. Collectively, these elements alter the urban energy balance by reducing sensible heat flux and increasing latent heat flux. The localised nature of these effects means that placement and connectivity are critical: isolated interventions yield limited benefits, whereas networks of green features can produce landscape-scale improvements. Design details such as species selection, soil depth, and connectivity to groundwater influence long-term effectiveness. Engineers increasingly integrate sensors and remote monitoring to evaluate performance and guide adaptive maintenance. Section C Empirical evidence demonstrates measurable benefits but also highlights variability. Field measurements and modelling studies commonly report near-surface air temperature reductions of approximately 1-5°C in well-shaded urban parks or street canopies relative to adjacent paved areas. Green roofs have been shown to retain a substantial proportion of incident rainfall - typically between 40% and 80% depending on substrate depth and storm intensity - thereby reducing runoff and sewer overflows. Permeable pavements can lower peak runoff volumes and delay peak discharge, with reported reductions ranging from around 20% to over 50% in some installations. Vegetation also contributes to air quality improvement: leaves intercept particulate matter and some gaseous pollutants, and tree cover is associated with reduced ambient concentrations at neighbourhood scales. Several cities have implemented large-scale greening initiatives that provide instructive lessons. In Singapore, a long-term policy emphasis on integrating greenery into urban development has yielded high tree canopy cover and extensive vertical greening on buildings, contributing to the city-state's reputation for livability in a tropical climate. London's municipal plans now prioritise green infrastructure to reduce flood risk and heat exposure, explicitly linking green corridors to transport and open-space planning. New York's programs have promoted street trees, green roofs and wetland restoration as complementary measures to traditional flood defences. These examples underline the importance of combining regulatory measures with incentives and community engagement. Nevertheless, research gaps remain, particularly regarding long-term performance under successive extreme events and the interactions between green and grey systems. Section D Despite demonstrated benefits, significant challenges constrain the widespread adoption of green infrastructure. Costs for installation and long-term maintenance can be substantial, particularly for engineered systems such as extensive green roofs and constructed wetlands. Governance challenges arise where responsibilities for green assets are dispersed across multiple agencies and private owners, complicating coherent planning and monitoring. Equity concerns are also prominent: wealthier neighbourhoods often receive greater investment in tree planting and park upgrades, while vulnerable communities face higher exposure to heat and flooding. Moreover, the effectiveness of green infrastructure under future climate scenarios is not guaranteed; prolonged droughts can reduce vegetation health and evapotranspiration rates, while extreme storms may overwhelm storage capacities. To maximise benefits, policy-makers should adopt integrated approaches that combine regulatory standards, financial incentives and targeted investment. Prioritising interventions in heat- and flood-prone neighbourhoods can address social inequities, while clear maintenance plans and performance monitoring improve longevity. Interdisciplinary assessment methods that incorporate hydrology, ecology, engineering and social considerations are necessary to design resilient networks. Finally, scaling up green infrastructure requires capacity-building at municipal levels and mechanisms to finance long-term stewardship, including public-private partnerships and community-based management models. Monitoring frameworks with standardised indicators are required to compare interventions across cities. Equally, public education and stakeholder participation increase acceptance and reduce vandalism or neglect.