Climate Change May Turn Thar Desert Green By Century’s End: Study

A study suggests that the Thar Desert, which is known for its arid expanse, could undergo a transformative shift because of the effects of climate change.

Even as many deserts across the globe are predicted to expand due to rising temperatures, the Thar Desert might defy this trend and could actually turn green within the next century, researchers said.

Covering over 200,000 square kilometres of territory, the Thar Desert is located partly in Rajasthan and partly in the Punjab and Sindh provinces of Pakistan.

Many studies have projected that the Earth’s deserts may grow under the influence of global warming. For example, according to experts, by 2050, the Sahara Desert could increase in size by over 6,000 square kilometres.

However, a recent, newly-published study in the journal Earth’s Future, puts forth an unexpected perspective on the Thar Desert.

The research team found that the mean rainfall over the semi-arid northwest regions of India and Pakistan witnessed an increase of 10–50 percent between 1901 and 2015. They did this by employing a combination of observations and climate model simulations. They said that under moderate greenhouse gas scenarios, this rainfall is anticipated to surge by 50–200 percent.

The researchers propose that coupled with a westward expansion of the current Indian monsoon, a reversal of this trend could radically transform the west and north-west regions of India into a humid ‘monsoonal’ climate. This transformation might, in turn, enhance food security for the burgeoning population of the country.

B.N. Goswami, from the Department of Physics at Cotton University in Guwahati, the study’s corresponding author, says that understanding the dynamics of the Indian summer monsoon is key to comprehending how the climate could turn the Thar Desert green.

Goswami says, “This happens due to the seasonal migration of the rainband or the active Inter-Tropical Convergence Zone (ITCZ) from south of the equator over the Indian Ocean in winter to about 25 degrees North in summer over the Indian continent.”

Brought about by climate change, the expansion of the warm water pool in the equatorial Indian Ocean, has led to a westward shift of the ITCZ. This, in turn, drives rain further westward during the summer months over the land.

According to Goswami, this phenomenon is crucial for the potential greening of semi-arid regions in north-west India and is unique to the Indian monsoon. The study emphasizes that this trend could lead to significant socio-economic and agricultural changes in the region.

The research team compiled data from South Asia over the past 50 years; it included P. V. Rajesh from the Indian Institute of Tropical Meteorology in Pune.

After analysing changes in monsoon concentration and duration, the team fed historical weather and sea surface temperature data into a climate model to predict future changes under various greenhouse gas scenarios.

Their analysis indicates that the Indian monsoon is indeed expanding westward; this is leading to a 25 per cent increase in the west and north-west and a 10 per cent decrease in mean rainfall in the northeast during the historical period.

The study authors emphasize the potential benefits of harvesting this rainfall; they also foresee substantial improvements in food productivity that could revolutionise the socio-economic landscape of the region.

However, the researchers underscore that even though this unexpected turn of events presents opportunities, it also raises major concerns.