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Greening of the Thar Desert: A Climate and Human Impact Study
Research from the Indian Institute of Technology Gandhinagar has revealed significant vegetation growth in the Thar Desert over the past two decades, attributed to climate change, increased monsoon rainfall, and enhanced groundwater extraction.
Global drylands account for approximately 41% of the Earth’s surface and are increasingly susceptible to the effects of climate change and shifts in land use, often leading to desertification. Despite challenges such as rising atmospheric water demand and expanding arid zones, human activities like irrigation and groundwater pumping have been instrumental in fostering vegetation growth across various dry ecosystems.
In India, drylands make up around 70% of total land and sustain nearly 1.5 billion individuals. Among these regions, the Thar Desert, spanning around 200,000 square kilometers across northwestern India and southeastern Pakistan, features the highest population density of any desert globally.
The findings of this comprehensive study, titled “Greening of the Thar Desert driven by climate change and human interventions,” published in Cell Reports Sustainability, utilized remote sensing technology alongside climate and hydrological records to analyze vegetation changes in the Thar region.
The climate conditions in the Thar Desert present a stark contrast, with winter temperatures dropping to 5°C and summer highs exceeding 50°C. The average annual rainfall is about 200 mm, primarily during the southwest monsoon season. Due to limited surface water, groundwater remains the predominant source for various uses including agriculture, domestic needs, and industry.
Research teams analyzed satellite-derived vegetation indices, precipitation data from multiple sources including CHIRPS, and groundwater metrics from in situ wells and satellite missions like GRACE and GRACE-FO.
Groundwater fluctuations were assessed through 728 observation wells across Rajasthan, with more than half of the data available spanning from 1996 to 2021. A total of 207 of these wells were situated within the Thar Desert. The changes in groundwater storage were monitored using satellite-derived data on terrestrial water storage anomalies.
Vegetation greenness in the Thar Desert increased by 38% between 2001 and 2023, with the most significant improvements noted in the northern-central regions. Notably, both the monsoon and non-monsoon periods exhibited trends of enhanced greening.
Seasonal evaluations indicated that during the summer monsoon, rainfall contributed to 66% of the vegetation growth, while groundwater accounted for 34%. Conversely, in non-monsoon months, groundwater’s contribution rose to 67%, with only 32% stemming from rainfall.
Annual precipitation within the Thar Desert surged by 64%, making it one of only four major desert ecosystems globally to show such a statistically significant increase during the same timeframe. The region also experienced the highest population growth compared to 14 major deserts analyzed worldwide from 2000 to 2020.
Urban development escalated by 50% to 800% from 1985 to 2020, while agricultural land expanded by approximately 300%. Satellite imagery indicated that much of this growth was concentrated in areas with intensified groundwater utilization.
The combined effects of rainfall and groundwater extraction have driven rapid urban and agricultural development in the Thar Desert. Projections suggest that continued greening is feasible, with climate models anticipating a 20% to 50% increase in mean annual precipitation through the end of the century across both low and high-emission scenarios.
However, groundwater depletion emerges as a significant concern, with both satellite and ground observations indicating long-term declines, raising questions about the sustainability of current extraction practices.
Future developments hinge on the ability to correlate increased monsoon rainfall with effective groundwater management. The rapid growth of irrigation, particularly through deep tube wells, has improved crop yields but has also resulted in decreased aquifer levels. Longer and intensified heatwaves, along with rising irrigation demands and dry season water shortages, pose a risk to the ongoing viability of agricultural expansion in the region.
The transformations witnessed in the Thar Desert illustrate the profound impact of strategic infrastructure investments, effective irrigation methods, and improved energy access in redefining arid landscapes. As the patterns of monsoon rainfall shift westward, this region is likely to undergo further ecological and economic transformations.
To maintain the ongoing greening trend, adaptation strategies will be critical. These may include cultivating drought-resistant crops, enhancing water recharge practices, and employing renewable energy sources for irrigation, all aimed at securing food and water resources for an expanding populace.
More information: Vimal Mishra et al, Greening of the Thar Desert driven by climate change and human interventions, Cell Reports Sustainability (2025). DOI: 10.1016/j.crsus.2025.100364
Source
phys.org