India’s green cover declined from approximately 36.95 per cent in 2001 to 31.35 per cent in 2025, while non-green surfaces expanded across the country, according to a new study by Climate Trends. The analysis found that non-green landscapes consistently recorded higher summer temperatures than vegetated areas, highlighting the role of green cover in moderating local heat.

The study, Assessment of Green Cover Dynamics and Their Influence on Summer Temperature across India Using MODIS Land Cover and ERA5 Reanalysis Data, found that the average summer temperature difference between green and non-green landscapes ranged from approximately 1°C to 2.5°C. Areas experiencing green-cover loss recorded a mean summer temperature increase of 0.26°C.

The findings suggest that vegetation loss can contribute to local warming, although the study also identifies broader regional climate change as a factor influencing temperature trends. Protecting and restoring vegetation could help reduce local thermal stress, but it cannot independently offset the effects of global warming.

“Vegetation is not merely an ecological asset; it is an important component of India’s climate-adaptation infrastructure,” said Dr Palak Balyan, Research Lead at Climate Trends.

The study comes amid growing concerns over extreme heat and its implications for public health, livelihoods and infrastructure. The India Meteorological Department reported that 2024 was the country’s warmest year since records began in 1901, with the annual mean temperature 0.65°C above the 1991–2020 average.

Vegetation Loss and the Local Heat Effect

The Climate Trends analysis used land-cover information from the Moderate Resolution Imaging Spectroradiometer (MODIS) and ERA5-Land temperature data to assess changes between 2001 and 2025. It examined summer conditions during March, April and May to understand how land-cover transitions corresponded with temperature patterns.

Vegetation helps regulate surface temperatures through shading and evapotranspiration, the process by which plants release water vapour into the atmosphere. Trees reduce the amount of solar radiation reaching the ground, while vegetation and soil moisture influence how energy is absorbed and released. When green landscapes are replaced by built-up areas, exposed ground or sparsely vegetated surfaces, these cooling mechanisms may weaken.

Dr Balyan said the persistent temperature difference between green and non-green landscapes demonstrated the importance of vegetation in regulating local thermal conditions.

“Protecting existing natural vegetation should therefore be treated as an adaptation priority, particularly in regions experiencing simultaneous green-cover loss and rising summer temperatures,” she said.

The findings are consistent with the Intergovernmental Panel on Climate Change’s assessment of nature-based cooling measures, which identifies urban trees, vegetation and green infrastructure as potential ways to reduce heat exposure. However, the extent of cooling depends on local climate, vegetation type, water availability and the surrounding built environment.

Regional Differences Require Targeted Action

The study found that green-cover loss was concentrated in parts of western India, the Indo-Gangetic Plain, central India and the peninsula. Localised gains were identified in portions of the northeastern states, the Himalayan foothills and scattered areas of southern and eastern India.

Temperature changes also varied geographically. Warming was particularly evident across northwestern and northern India, while localised cooling occurred in parts of central and southern India. These variations indicate that national averages can obscure differences in local land-use patterns and climate conditions.

The findings have implications for urban planning, particularly in rapidly expanding cities where construction can replace trees, open spaces and other vegetated landscapes. Protecting mature trees, retaining existing green spaces and integrating vegetation into streets and public areas could help reduce heat exposure, particularly in vulnerable neighbourhoods.

However, restoration must be planned around local ecological conditions. Newly planted trees cannot immediately provide the shade offered by mature canopies, and their survival depends on suitable species, soil conditions, water availability and long-term maintenance. Protecting established vegetation is therefore an important complement to new planting initiatives.

Green Cover Cannot Replace Broader Climate Action

The study emphasises that land-cover changes are not the only drivers of summer temperatures. Both green and non-green landscapes experienced warming during the study period, indicating the continuing influence of broader climatic conditions.

Dr S K Dhaka, Professor of Atmospheric Physics at the University of Delhi, cautioned against treating vegetation restoration as a standalone solution.

“Vegetation restoration can reduce local thermal stress, but it should not be viewed as a substitute for broader climate action,” he said.

Temporal variation in green and non-green land cover across India

He added that warming observed even in areas that remained continuously green showed that large-scale climatic forces continued to influence regional temperatures.

“India therefore needs a dual strategy: prevent further loss of established vegetation while implementing scientifically targeted restoration in heat-vulnerable regions, alongside stronger action on water management, urban planning and greenhouse-gas emissions,” Dr Dhaka said.

The distinction is important because increasing vegetation alone cannot eliminate heat risks associated with rising background temperatures. Effective adaptation requires combining nature-based measures with emissions reduction, appropriate urban design and improved water management.

Aarti Khosla, Founder-Director of Climate Trends, said the study highlighted the practical consequences of losing vegetation.

“The study puts a number on something we’ve long argued, that vegetation is not a biodiversity afterthought, but a climate-adaptation infrastructure,” she said.

“Where green cover has disappeared, temperatures have risen with it, and that is a cost India’s communities are already paying for,” Khosla added.

She also pointed to international biodiversity commitments, including the target of restoring 30 per cent of degraded ecosystems by 2030, arguing that the gap between commitments and implementation has consequences for climate resilience.

The study recommends protecting existing vegetation, preventing avoidable green-cover loss and promoting ecological restoration as part of sustainable land management.

Its central message is that green cover should be considered more than an environmental amenity. While vegetation cannot prevent all forms of warming, conserving it can help moderate local temperatures and reduce thermal stress. As India faces increasing heat risks, integrating vegetation protection into climate adaptation and development planning could help build more resilient communities.

The atmospheric systems that bring winter rain and snow to the Himalayas are changing in ways that complicate a familiar assumption that more weather systems mean more precipitation.

A study published in the International Journal of Climatology in March 2026 examined winter precipitation across the Western Himalayan region over two 30-year periods, 1961–1990 and 1993–2022. Using ERA5 atmospheric reanalysis data, the researchers found that Western Disturbances and the number of days associated with them had increased, while the density of their tracks across the study region had declined as their paths shifted northward.

The study also identified a decline in large-scale precipitation. A greater proportion of the precipitation that did occur fell as rain rather than snow, partly offsetting the reduction in snowfall. These findings point to changes in the location, form and mechanisms of precipitation, rather than a uniform increase in rainfall across the Himalayas.

What are Western Disturbances?

Western Disturbances are eastward-moving weather systems that originate in the Mediterranean and adjoining regions and travel towards South Asia. They are embedded in the westerly flow of the middle and upper atmosphere and are an important source of winter precipitation over northwestern India and the western Himalayas.

When these systems reach the mountains, their effects depend on several interacting factors: the amount of moisture they carry, the strength and direction of atmospheric winds, the temperature profile of the air and the shape and elevation of the terrain.

As moist air rises over mountain slopes, it cools and water vapour condenses into cloud droplets or ice crystals. Depending on atmospheric conditions, precipitation can fall as rain or snow. The distribution of precipitation varies with the system’s track and intensity, as well as local topography. A shift in the path of a Western Disturbance can therefore change which valleys and mountain slopes receive precipitation, even if the overall number of systems increases.

Why Frequency Alone Does Not Explain the Rainfall

The 2026 study highlights an important distinction between the occurrence of Western Disturbances and the precipitation they produce. Although the researchers found an increase in the number of disturbances and associated days, their analysis showed that fewer tracks passed through the Western Himalayan study region. The northward shift was associated with a decline in large-scale precipitation.

The study also found that rising temperatures increased the atmosphere’s capacity to hold moisture, while weaker vertical winds reduced the upward movement of air. Reduced transport of moisture into the upper troposphere also affected cloud microphysical processes that support large-scale precipitation.

These processes help explain why a warmer atmosphere does not automatically translate into greater precipitation everywhere. Temperature, moisture availability, vertical air movement and the location of weather systems all influence how much precipitation forms and where it falls.

The findings also have implications for snowfall. When temperatures rise, a larger share of precipitation can fall as rain instead of snow, depending on conditions within the atmosphere and near the surface. Such a change can affect seasonal snow accumulation and the timing of water entering Himalayan river systems.

How Does Climate Change Fit Into the Picture?

Climate change alters the background conditions in which Western Disturbances develop and travel. Rising temperatures influence atmospheric moisture, while changes in circulation can affect the systems’ tracks and the way they interact with mountain terrain.

However, researchers have identified different trends across different parts of the wider Himalayan region. Findings from the Western Himalayas cannot automatically be applied to Nepal or the eastern Himalayas, where the influence of weather systems, topography and moisture sources may differ.

The October 11, 2026, flash flood in Nepal’s Budhi Gandaki river system illustrates why this distinction matters. According to the International Centre for Integrated Mountain Development (ICIMOD), a preliminary assessment suggested that a landslide may have blocked the river before the temporary barrier failed, releasing water, sediment and debris downstream. The organisation said further investigation was needed to establish the event’s precise trigger.

The flood, therefore, cannot be attributed to a change in Western Disturbances on the available evidence. The scientific questions surrounding the event include the mechanics of the landslide, the temporary river blockage and the release of the accumulated water. Establishing whether weather conditions contributed to the initial slope failure requires separate evidence.

What Scientists Need to Examine Next

Understanding changes in Himalayan precipitation requires researchers to look beyond the number of Western Disturbances recorded in a season. Their tracks, intensity, moisture transport, vertical wind patterns and the proportion of rain and snow all need to be examined together.

Long-term observations and atmospheric reanalysis can help identify regional trends, while measurements of snow cover, precipitation and mountain hydrology can show how those changes affect water availability. Comparisons across the western, central and eastern Himalayas are also necessary to establish where trends are consistent and where they differ.

The central finding is that changes in atmospheric circulation can redistribute precipitation even as the climate warms. For the Himalayas, where snow accumulation, river flow and mountain ecosystems depend on the timing and form of precipitation, understanding these regional differences is essential to explaining how the water cycle is changing.

The torrential rainfall that flooded Istanbul on October 14–15 has highlighted a growing challenge for cities confronting extreme weather: how to prepare for heavier rainfall when the extent of climate change’s influence varies across regions, and the damage depends partly on how urban landscapes are built.

A new analysis by the ClimaMeter research team finds that weather patterns similar to those behind the floods now bring about 7% heavier rainfall and 9% stronger winds than comparable patterns recorded between 1950 and 1987. Temperatures in the region of heaviest rainfall are up to 1.5°C higher than in the historical comparison period.

However, the increase in rainfall was not statistically significant over Istanbul itself. The researchers identified significant rainfall increases across parts of western and north-western Anatolia and along the Black Sea coast north of the city, while natural climate variability also contributed to the event.

The floods triggered 1,277 flooding incidents and 15 landslides across Istanbul, according to the analysis. ClimaMeter reported 194 millimetres of rainfall at Ömerli in the Beykoz district, while Istanbul’s disaster coordination centre, AKOM, reported 277.1 millimetres in Beykoz during the event. Two people died, 595 people were evacuated after becoming trapped, and roads and schools were affected.

The findings underline an important distinction: climate change can alter the conditions associated with extreme rainfall, but it does not explain every aspect of an individual flood. Urban drainage, land use and exposure determine how rainfall translates into damage.

What climate attribution reveals

The ClimaMeter analysis compared the atmospheric conditions of October 14–15, 2026, with similar weather patterns from 1950–1987 and 1988–2025. Using the European Centre for Medium-Range Weather Forecasts’ ERA5 reanalysis data, researchers examined changes in precipitation, temperature and wind.

They estimated that about 3% of the rain-linked damage associated with the event was attributable to human-driven climate change, with an estimated range of 1–4%. This is a rainfall-based attribution estimate, not a calculation of the proportion of all damage caused by global warming. The methodology does not account for drainage capacity, impermeable surfaces or construction along streambeds.

The physical basis for heavier rainfall is well established. The Intergovernmental Panel on Climate Change (IPCC) explains that the atmosphere can hold approximately 7% more water vapour for every 1°C of warming. When atmospheric conditions are favourable, additional moisture can contribute to more intense precipitation.

The IPCC’s Sixth Assessment Report concludes that heavy precipitation has become more frequent and intense across most land regions with sufficient observational coverage, primarily because of human influence. Regional trends, however, are not uniform, and Mediterranean precipitation patterns are affected by considerable natural variability.

The Istanbul findings therefore point to a need for preparedness without overstating the evidence. The absence of a statistically significant local rainfall trend does not mean the city faces no climate risk. It means that the specific analysis did not establish a significant rainfall increase over Istanbul for the weather pattern examined.

Urban development can magnify flood damage

How a city responds to rainfall depends on more than the volume of water falling from the sky. Roads, buildings and other impermeable surfaces reduce the amount of water absorbed into the ground, increasing runoff. If drainage systems cannot carry away the additional water, streets and low-lying areas can flood rapidly.

Research conducted in Istanbul provides evidence of how planning decisions can influence this risk. A 2021 study by Seda Ertan and Rahmi Nurhan Çelik, published in Sustainability, modelled flood scenarios across a 1,653-hectare catchment of the Kağıthane Stream.

Representational image.image credit:Pexels

The researchers examined measures including green roofs, permeable road surfaces, rainwater collection and drainage channels. Their results indicated that green infrastructure could reduce surface runoff and peak flow rates, as well as the area inundated and the number of structures exposed to flood risk.

The findings suggest that flood management should extend beyond expanding conventional drainage infrastructure. Permeable surfaces can allow more rainwater to enter the ground, while green roofs and rainwater collection systems can help retain water before it reaches drainage networks. Their effectiveness nevertheless depends on local conditions and the intensity of rainfall.

A separate study published in the Journal of Flood Risk Management in January 2025 examined flood exposure and vulnerability in Istanbul’s Pendik district. The researchers found that flood-prone areas were associated with lower land values and greater concentrations of socially disadvantaged residents, including older people, refugees and people with lower levels of education.

The study identified substantial differences in vulnerability within the district. About 21% of the assessed Kaynarca basin fell into the study’s very-high-vulnerability category, while 20.4% was classified as high vulnerability. These classifications reflect the study’s specific assessment framework and should not be interpreted as estimates for Istanbul as a whole.

The research highlights an important dimension of urban resilience: communities do not experience flood risk equally. Housing conditions, access to resources, the location of residential areas and the ability to respond to warnings can influence how severely households are affected.

Building resilience beyond emergency response

The implications extend beyond Istanbul. Cities facing intense rainfall need to combine reliable drainage systems with land-use planning, early-warning mechanisms and protection of natural waterways.

Nature-based approaches can complement conventional flood defences. A 2024 review published in npj Urban Sustainability examined the role of nature-based solutions in flood-risk management, emphasising the importance of considering social and ecological outcomes alongside physical protection. Wetland restoration, urban green spaces and restored stream corridors can help retain water and reduce runoff, although they cannot eliminate the risk of flooding during extreme events.

For Istanbul, the findings also raise questions about development near waterways and the preservation of natural drainage routes. A recent report by the Turkish news agency Anadolu Agency, published on October 20, quoted Istanbul Technical University disaster-management researcher Ömer Ekmekcioğlu warning that heavily urbanised catchments and areas where natural drainage systems have been altered require particular attention.

The ClimaMeter team estimated that approximately 14.6 million people and US$558 billion in economic activity were exposed within the wider rainfall-hazard area. These figures represent exposure to the identified hazard, not the number of people directly affected or the economic losses incurred during the floods.

The broader lesson is that climate attribution and urban planning answer different but connected questions. Climate science helps establish how warming may change the intensity of weather hazards; urban-risk research examines why certain places and communities suffer greater consequences.

Istanbul’s floods demonstrate why both are necessary. Preparing for a changing climate requires understanding the rainfall, but reducing the damage also depends on where cities build, how they manage water and whether their infrastructure protects the people most exposed to risk.