Latest news with #UHI
Time of India
3 days ago
- Climate
- Time of India
Buildings & asphalt surfaces, not just climate, heating up Bengaluru, finds IISc study
Bengaluru: Bengaluru is warming up — and not just because of global climate change. A new scientific study has found that the city itself is becoming a heat trap because of the way its land is being used. This is called Urban Heat Island (UHI) effect, where temperatures inside the city are significantly higher than in nearby rural or forested areas. The reason? Concrete and asphalt surfaces absorb and store heat, while the loss of green spaces and waterbodies removes natural cooling systems. The Indian Institute of Science (IISc) study is one of the first to provide micro-level data, showing exactly how land use choices at even the smallest scales — like an individual plot or street — can affect urban temperatures. If Bengaluru wants to stay liveable in the coming decades, reversing some of these trends is not optional; it's essential. You Can Also Check: Bengaluru AQI | Weather in Bengaluru | Bank Holidays in Bengaluru | Public Holidays in Bengaluru What has changed in city? Researchers from IISc and partner institutes studied satellite images from 1973 to 2025 to map how Bengaluru's landscape has changed over the decades. The findings are stark: ■ Built-up areas have expanded by 1,078%. In 1973, just 7.9% of Bengaluru was built-up (meaning buildings, roads, and other paved areas). Sponsored Links Sponsored Links Promoted Links Promoted Links You May Like Fernandina Beach: Here's The Average Price of a 6-Hour Gutter Upgrade Read More Undo by Taboola by Taboola In 2025, this reached 87.6%. ■ Vegetation cover has reduced by 88%. Parks, tree cover, and open green spaces have disappeared across large parts of the city. ■ Waterbodies have shrunk by 79%. The number of lakes has fallen from 756 in 1973 to 216 in 2023. Many remaining lakes are encroached or polluted. How much hotter is the city? The researchers used satellite-based thermal data to calculate Land Surface Temperature (LST) — the temperature of the ground, buildings, and other surfaces. ■ Maximum LST recorded: 48°C ■ Minimum LST recorded: 29.8°C ■ Average LST: 38.6°C What else was identified? ■ 15.4 sqkm of heat hotspots: Areas that regularly record very high temperatures. ■ 23.8 sqkm of heat sinks: Pockets that remain cooler, usually because of green cover or waterbodies. ■ 545.3 sqkm of the city face unfavourable ecological conditions due to high temperatures and poor thermal comfort. Why is this happening? Heat islands form because of how cities are built and planned. In Bengaluru: ■ Buildings, roads, and pavements absorb solar heat during the day and release it at night, keeping local temperatures high. ■ Trees and lakes, which usually cool the environment through shade and evaporation, have been removed or degraded. ■ The city's flat terrain means there is little natural drainage of hot air. Detailed land use & temperature findings The researchers went beyond broad city-level data and looked at micro-level patterns, even analysing land use within small plots, the size of an individual housing site. Their key findings include: ■ Barren land and fully urbanised areas are the hottest. Fully barren areas had an average surface temperature of 39.9°C; fully urban (concrete-heavy) ones recorded 39.7°C. ■ Vegetated areas and waterbodies are the coolest, while those dominated by waterbodies having temperatures of around 31°C. ■ Mixed-use areas (some vegetation, some built-up) have moderate temperatures. The more green space a plot retains, the cooler it stays. UHI impact on daily life ■ Higher electricity bills (more fans & air-conditioners). ■ Increased risk of heat stress and health problems, especially for the elderly and children. ■ More pollution, as heat worsens air quality. ■ Reduced quality of life, with fewer comfortable outdoor spaces. HOW TO IMPROVE The IISc researchers have made specific recommendations: ■ Policy suggestions — Retain at least 30% green space at the plot level. New buildings shouldn't cover the entire plot with concrete or structures. — Create mini-forests in each city ward. — Rejuvenate lakes and prevent further encroachments. — Connect scattered tree patches to create continuous green corridors. — Promote green roofs and walls. — Use reflective building materials to reduce heat absorption. ■ Planning & governance — Incorporate these findings into the upcoming Bengaluru Master Plan 2031. — Involve local communities in managing neighbourhood green spaces, parks, and lakes. — Strengthen decentralised governance as per the Nagarpalika Act, so local wards can manage their own green areas.
The Hindu
09-07-2025
- Science
- The Hindu
Bengaluru too hot? Dramatic increase in built-up area to blame, says study
As Bengaluru's once temperate climate turning increasingly warmer continues to be in the news, a newly published study reveals that 15.41 sq. km area in the city has very high temperature, even as land uses assessed using temporal remote sensing data from 1973 to 2025 showed a 1,078% increase in urban (built-up) area during the last five decades — from 7.97% in 1973 to 87.64% in 2025. Only 168.93 sq. km area was under favourable conditions as per the Urban Thermal Field Variance Index (UTFVI), which evaluates the well-being of the environment concerning ecological thermal comfort while considering the Urban Heat Island (UHI) effect, whereas 545.25 sq. km was under unfavourable ecological conditions. UHI archipelago, representing the combined effect of multiple localised heat islands, forming a broader area of elevated temperatures, was observed especially in the eastern and northern parts of the city, the study added. Ambient air details 'Temporal ambient air temperature details complied from the India Meteorological Department monitoring stations in Bengaluru reveal that ambient temperature has shown an increasing trend with the alteration in landscape structure with an increase in paved surfaces (buildings, roads, etc.) and decline of natural porous surfaces (vegetation, lakes, etc.),' the study said. May temperatures went from 16 °C to 18 °C in the 70s, 19 °C in the 90s, 21 °C in 2000, 28 °C in 2010, and 34 °C in 2025, it added. These findings coincide with the comparison of daily maximum temperatures from 2015 to 2024 against the World Meteorological Organization's standard 1991-2020 climatological baseline, which showed that over the last 10 years, traditionally cooler cities such as Bengaluru and Mumbai have been experiencing more days with above-average temperatures than Delhi. The study, 'Urban heat island linkages with the landscape morphology,' was conducted by T.V. Ramachandra, Rajesh Singh Rana, S. Vinay and Bharath H. Aithal, and published in the journal Nature on July 8. The micro level analyses was initiated to recommend appropriate building regulation to enhance the thermal comfort by the Directorate of Town and Country Planning following the high summer temperatures that the city witnessed in 2024. The study says that the Chief Town Planning Officer responded positively of incorporating the outcome of the research in the proposed Revised Master Plan 2031. Bengaluru's growth story According to the researchers, Bengaluru witnessed spatial expansion in the mid-2000s with the formation of the Bruhat Bengaluru Mahanagara Palike by including adjacent rural landscapes, which led to the conversion of agricultural land to paved areas. 'The city landscape witnessed a 1,078% increase in built-up with a decline of 88% vegetation cover and 79% water bodies, leading to the transition of the landscape from porous to paved surfaces, affecting the hydrology, ecology, and socio-economic aspects. The urban trajectory in Bengaluru city exhibits distinct phases; from 1973 to 1992, steady annual growth of 1% driven primarily by the establishment of nationalised public sector industries, globalisation and subsequent relaxation in markets during the 90s witnessed by the emergence of the information technology (IT) sector,' the study said. It added that the post-2002 era witnessed annual growth rates surging to 2.01% due to the proliferation of private industries and Special Economic Zones (SEZs). These developments generated employment opportunities and pushed a rapid conversion of peri-urban landscapes for residential and commercial development. The 2012–2021 period was characterised by intense urban growth driven by the increasing IT sector and the associated influx of population and annual urbanisation reached 3%, it said, adding that post-2021 witnessed annual urbanisation of 0.5% with the proliferation of residential layouts and a shift towards lower-density urban sprawl beyond the BBMP, engulfing the adjacent agrarian spaces. Policy recommendations Prof. Ramachandra from the Indian Institute of Science, who is one of the authors of the study, said policy recommendations to mitigate UHIs in cities should include increasing and protecting green spaces, integrating green infrastructure into urban development plans, a mini forest of native species in each ward to moderate local temperature, maintaining 30% open spaces with green cover at plot levels, connecting fragmented tree patches for promotion of ecosystem health and sustainability, rejuvenating the 216 lakes to retain rainwater and facilitate groundwater recharge, among others.
Yahoo
09-07-2025
- Science
- Yahoo
Solar array proposed for Skye's Gaelic college
Plans have been lodged for a solar array at Sabhal Mòr Ostaig UHI - Scotland's centre for Gaelic language and culture - on Skye. The renewable energy scheme would comprise more than 200 panels and has been proposed for the college's Àrainn Chaluim Chille campus. Full planning permission has been sought from Highland Council. Sabhal Mòr Ostaig is part of the University of the Highlands and Islands (UHI) network. The college and UHI have been asked for comment on the proposals. More stories from the Highlands and Islands News from the Highlands and Islands on BBC Sounds Sabhal Mòr Ostaig was founded in Skye in 1973 by Sir Iain Noble, a businessman, landowner and Gaelic activist. It was first set up in a former farm steading, and over the years more modern facilities have been added to the site on the Sleat peninsula. Today it offers higher and further education, including PhDs, and has been described as the only facility of its kind in the world. Last year, the first 17 properties of Skye's first new village in more than 100 years opened near the college. Kilbeg is eventually to have about 100 homes in total. There is an expectation the village will attract Gaelic speakers, though the development is open to anyone who wants to live or work in the area. Gaelic boost expected from island's first new village for a century In pictures: 50 years of Skye's Sabhal Mòr Ostaig Sabhal Mòr Ostaig UHI Highland Council
India Today
09-07-2025
- Climate
- India Today
Cloudy with a chance of error: Why IMD is struggling to get Delhi's rain right
This monsoon season, Delhi appears rather unlucky when it comes to rainfall. Although the skies over the national capital have often been filled with clouds, the expected precipitation has largely eluded the neighboring states, which have enjoyed abundant rains, Delhi has experienced a significant deficit, receiving almost 25% less rainfall than usual from June 1 to July this monsoon has been overall favourable for India. The country has recorded about 15% more rainfall than the normal levels during the initial 40 days of the States surrounding Delhi have benefited from this surplus. Haryana noted an impressive 32% increase in rainfall, Punjab saw 15% above-normal precipitation, Rajasthan led with an astonishing 121% increase, and Uttarakhand recorded 22% more rain. Even Uttar Pradesh managed a slight rise of 1%, making Delhi's deficit all the more notable. Delhi's rainfall is governed by multiple large climatic systems. (Photo: PTI) Will Delhi get good rainfall in the days to come?The India Meteorological Department's (IMD) prediction for Delhi's monsoon rainfall after the onset on June 29 largely went wrong. Though the monsoon arrived two days ahead of schedule, expectations of heavy rain across the city were not IMD had forecast significant rainfall from July 6 onwards, anticipating that the monsoon trough, which had moved northward from central India, would linger over Delhi and bring consistent as explained by Dr. R K Jenamani, a senior scientist at IMD, "the active monsoon trough remained over Delhi for only a few hours during the last weekend before shifting northwards toward Punjab. Currently, the trough is positioned roughly 150 kilometers north of Delhi near Chandigarh."This shift has significantly reduced the chances of substantial rainfall in Delhi in the coming days. As a result, core parts of Delhi experienced only light and scattered showers, while some outer regions, like Najafgarh, received moderate gap between forecasted and actual rainfall shows the challenges in predicting monsoon behaviour in densely populated urban areas. States surrounding Delhi have benefited from this surplus. (Photo: PTI) Scanty rainfall in DelhiDelhi, one of India's most densely populated urban centers, has witnessed extensive concretization over the rapid urbanisation has significantly contributed to the Urban Heat Island (UHI) effect, where built-up areas experience considerably higher temperatures than their rural Delhi, particularly in the heavily developed South and East regions, temperatures can be 2C to 9C hotter due to UHI. This temperature disparity directly influences local weather, especially precipitation UHI effect alters convection and atmospheric dynamics over the city. Warmer urban surfaces heat the air above, affecting local wind patterns and cloud formation. These changes can suppress rainfall over dense urban zones, as convection currents weaken or shift, leading to reduced phenomenon results in a complex interaction of atmospheric variables that disturb the usual cycle of rainfall, aggravating water scarcity issues in the Delhi's rainfall is also governed by other larger climatic systems. According to the India Meteorological Department (IMD), rainfall depends on the convergence of several instance, the monsoon trough in 2023 remained active for a brief period, limiting overall monsoon rainfall. Furthermore, Western Disturbances (WD)—frontal weather systems traveling from the Mediterranean—play a vital role in northern India's weather, including Delhi's R K Jenamani, meteorologist and expert, explains that most Western Disturbances this year passed to the north of Delhi, failing to bring significant rain to the capital. Their northward track, combined with short-lived monsoon trough activity, led to a rainfall deficit. advertisementThus, while UHI intensifies local warming and modifies convection, India's complex monsoon system and Western Disturbances importantly regulate the amount and timing of rainfall in there are challenges faced by meteorological departments in making precise monsoon forecasts for metropolitan areas like Delhi, where climatic conditions can vary drastically over short also highlights the need for continuous improvements in weather prediction models that can account for the complex interplay of local atmospheric and environmental factors.- EndsMust Watch
BBC News
09-07-2025
- Business
- BBC News
Solar array proposed for Isle of Skye's Sabhal Mòr Ostaig UHI
Plans have been lodged for a solar array at Sabhal Mòr Ostaig UHI - Scotland's centre for Gaelic language and culture - on renewable energy scheme would comprise more than 200 panels and has been proposed for the college's Àrainn Chaluim Chille planning permission has been sought from Highland Mòr Ostaig is part of the University of the Highlands and Islands (UHI) network. The college and UHI have been asked for comment on the proposals. Sabhal Mòr Ostaig was founded in Skye in 1973 by Sir Iain Noble, a businessman, landowner and Gaelic was first set up in a former farm steading, and over the years more modern facilities have been added to the site on the Sleat it offers higher and further education, including PhDs, and has been described as the only facility of its kind in the year, the first 17 properties of Skye's first new village in more than 100 years opened near the is eventually to have about 100 homes in is an expectation the village will attract Gaelic speakers, though the development is open to anyone who wants to live or work in the area.
