**Executive Summary**
The Ministry of Science & Technology reported that satellite data analysis of Uttarakhand's vegetation from 2001 to 2022 reveals declining vegetation trends linked to climate change and human activities. Researchers used Google Earth Engine (GEE) and the Normalized Difference Vegetation Index (NDVI) to analyze changes. The study, published in *Environmental Monitoring and Assessment*, highlights the need for intervention and serves as an early warning system.
**Key Points / Main Content**
* **Study Overview:**
* Satellite data was used to study vegetation changes in the Himalayas, revealing climate sensitivity and seasonal resilience.
* The study period was from 2001 to 2022, focusing on Uttarakhand.
* GEE was used to process satellite data for environmental monitoring and Earth observation.
* NDVI and EVI were used to analyze vegetation changes.
* **Findings:**
* NDVI and EVI are highest after the monsoon and lowest before it, with clear monthly, seasonal, and yearly variations.
* Declining vegetation trends are linked to deforestation, agricultural expansion, illegal logging, and increasing pollution.
* Pollution affects vegetation unevenly, compounding climate change stress.
* **Implications:**
* Changes threaten biodiversity, water resources, and the natural balance.
* Satellite science acts as an early warning system for policymakers and communities.
**Impact Analysis**
**Stakeholder: Policymakers and Communities**
* **Impact:** Need to understand where intervention is needed most urgently to mitigate the negative impacts.
* **Action Required:** Use the study's findings and satellite data as an early-warning system to inform intervention strategies.
Key Entities Referenced
Uttarakhand: The region where declining vegetation is being studied via satellite data from 2001-2022.
Google Earth Engine (GEE): A global platform used for processing satellite data to monitor environmental changes and track vegetation changes in Uttarakhand.
Normalized Difference Vegetation Index (NDVI): A simple measurement used to analyze changes in vegetation from satellite data.
Aryabhatta Research Institute of Observational Sciences (ARIES): Research institute which collaborated with the Department of Science and Technology and international collaborators to track Uttarakhand's vegetation changes using Google Earth Engine.
Department of Science and Technology (DST): An autonomous institute which collaborated with ARIES to track Uttarakhand's vegetation changes using Google Earth Engine.
Ministry of Science & Technology
Satellites warn of declining vegetation in the
Uttarakhand hills
Posted On: 09 FEB 2026 2:47PM by PIB Delhi
Satellites keeping an eye on the vegetation of the Himalayas, responding to changing seasons with
reviving grasslands, deepening colour of forests, and flora of valleys altering, reveal a story of climate
sensitivity, seasonal resilience, and growing concern.
Mountain ecosystems are particularly sensitive to climate change, which exacerbates global risks and
disasters. Climate change significantly affects global average surface temperatures, alters precipitation
patterns, and influences vegetation dynamics, underscoring the importance of localised monitoring at
various spatial and temporal scales.
Google Earth Engine (GEE)¸ a global platform that processes vast amounts of satellite data, is widely used
for environmental monitoring and Earth observation, including studies of land degradation, soil and dust
dynamics, urban growth, temperature changes, and health. It simplifies large-scale analysis by reducing
data preprocessing and storage needs.
Researchers from the Aryabhatta Research Institute of Observational Sciences (ARIES), Nainital, an
autonomous institute of the Department of Science and Technology (DST), along with collaborators from
India and abroad, turned to GEE to track Uttarakhand’s vegetation from 2001 to 2022, along with
pollution and climate responses.
They used a deceptively simple measurement, the Normalized Difference Vegetation Index (NDVI), to
analyse changes in vegetation.
The results of the research by the team led by Dr Umesh Dumka from ARIES, along with international
collaborators, published in Environmental Monitoring and Assessment (a Springer Nature Publication),
revealed a story of climate sensitivity, seasonal resilience, and growing concern.Fig 1: Seasonal spatial variations of NDVI for 22 years (2001–2022), (a) winter, (b) pre-monsoon, (c)
monsoon, and (d) post-monsoon
Lower values of NDVI correspond to barren areas, such as rock, sand, water, exposed soils, or snow, while
higher NDVI values indicate dense green vegetation, including forests, croplands, and wetlands.
The study also analyzed EVI (Enhanced Vegetation Index; similar to NDVI but with improved sensitivity
in high-biomass areas) and climate variables and their relationships in Uttarakhand, northern India.
Fig 2: Seasonal spatial variations of EVI for 22 years (2001–2022), (a) winter, (b) pre-monsoon, (c)
monsoon, and (d) post-monsoon.
The spatial and time-series plots generated via GEE were employed to analyse changes and trends across
the study area, while Pearson’s correlation assessed the effects of climate variables on NDVI and EVI. The
results show that NDVI and EVI are highest after the monsoon and lowest before it, with clear monthly,
seasonal, and yearly variations. Over the last two decades, the natural rhythms have begun to shift.
The researchers observed declining vegetation trends, linked to deforestation, agricultural expansion,
illegal logging, and increasing pollution from urban and industrial sources. The data suggest that pollution
doesn’t affect vegetation uniformly—it hits certain locations harder, compounding the stress caused by
climate changeThese changes threaten biodiversity, water resources, and the natural balance that millions of people
downstream depend on.
The study shows that modern satellite science can act as an early-warning system, helping policymakers
and communities understand where intervention is most urgently needed.
Publication link: https://link.springer.com/article/10.1007/s10661-025-14804-x
https://scienmag.com/google-earth-engine-insights-on-uttarakhands-vegetation-dynamics/
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