Climate Change in the Ganges River Basin

A NextGen Blog post by Johanna Mitra, Stony Brook University.

All Photos © Alison M. Jones.

This is the latest post to our NWNL NEXTGEN BLOG series. Since 2007, NWNL has supported watershed education with college internships and blogging opportunities. This NWNL NEXTGEN BLOG series posts students’ essays; sponsors a forum for our student contributors; and invites upper-level students to propose work focused on watershed values, threats and solutions.

Johanna Mitra is currently an undergraduate student at Stony Brook University. She is majoring in ecosystems and human impact with a focus on wildlife conservation and minoring in geospatial science. Read her earlier posts here.

India’s Ganges River Basin is one of the most critical freshwater systems in South Asia, running 1,569 miles from the Himalayan Mountains southeast to the Bay of Bengal. Nearly half a billion people rely on this river basin for its waters. For Hindus, the Ganges is an especially sacred river and thus the site of numerous religious celebrations and daily rituals.1No Water, No Life

People bathing in the Ganges River from Varanasi’s Dharmadfoeink Ghat

As the Ganges River supports one of the most populated regions of the world, it’s no surprise that the river suffers from severe pollution and contamination due to human activity. However, there exists another, more subtle threat that’s perhaps more dangerous to this great river system: climate change.

The Ganges’ dependency on the monsoon season and ice-melt from the Himalayas for its flow makes the river especially sensitive to increased temperatures and shifting rainfall patterns. The river’s delta, spanning Bangladesh and India’s West Bengal, is one of the most densely populated areas in the world. There, the threat of sea level rise would displace millions of inhabitants.2National Geographic Society The World Wildlife Fund now considers the Ganges one of the world’s most endangered rivers, a status not to be taken lightly considering its cultural significance and its role as the region’s leading water source.

Boats in the Ganges tied up amidst trash, at edge of a Varanasi ghat

Flooding and Drought

Floods have long been synonymous with the Ganges as a result of the monsoon season. Each year from June to September, India is inundated with massive amounts of rain, which have traditionally provided plentiful water for people and crops after their dry season. The monsoons are an especially critical water source for the river, since during these three months they provide the region with 70% of its total rainfall for the year.3Amrith, Sunil However, flooding in this river basin is becoming increasingly severe as the monsoon seasons have become unpredictable and more relentless. Warming oceans, coupled with hotter temperatures on land, have resulted in monsoon rains occurring later in the year and greater amounts of rainfall coming all at once. Those living and cultivating crops in the Ganges floodplains are not prepared to handle these unpredictable weather extremes. In 2019, flooding displaced about 1.2 million people from their homes. Death rates from these natural disasters continue to rise each year.4Chandrashekhar, Vaishnavi

Boy gathering water from manmade lake still full of winter rains

Among current worrisome trends is the threat of longer and more frequent dry spells that precede these extreme flooding events. Given that the river’s flow is so dependent on ice melt from Himalayan glaciers in the north, glacial recession due to climate change threatens even greater likelihoods of drought downriver. For example, the Gangotri Glacier is the largest glacier in India; and its melting ice provides as much as 70% of the Ganges’ volume. Yet, the glacier has been shrinking at a rate of 22 meters per year, and that rate is expected to increase given the current global warming trajectory.5Sehgal, Jasvinder Not only does rapid ice-melt increase the risk of floods; but as the glaciers receive less and less snow, the amount of water they can provide to the Ganges and its tributaries will decline.6Sehgal, Jasvinder This has dangerous implications for India’s agricultural sector since a third of it is based in the Ganges River Basin and crops require an ever-growing supply of water to be sustained.7Rally for Rivers

Sea Level Rise

The Ganges River Delta faces its own persistent threat from rising sea levels. The Bay of Bengal, the terminus of the Ganges, already lies very close to sea level, with some of its deltaic plains only less than a meter above the water.8GBSNP The water levels in this area are predicted to rise by as much as 1.4 meters by the end of the century, threatening approximately 200 million people living within the delta.9Varma, GBSNP Also, the effects of sea level rise on the delta will be exacerbated by subsidence and sinking of the delta plains themselves. This process is often the result of human activity further upstream altering a river’s natural flow.

In the case of the Ganges River, the construction of more than 1,000 dams on the river and its tributaries have significantly altered its flow. While some dams are built to produce hydroelectricity, others are for creating reservoirs or diverting water to other river systems, such as India’s 7,500-foot long Farakka Barrage.10Chandrashekhar, Vaishnavi A more recent development in this river basin is the National River Linking Project, the government’s plan to combat water scarcity in the region by connecting 44 rivers in the basin through a series of 29 canals.11Higgins, Stephanie A. The project will also require the construction of 43 more dams, all of which have the potential to trap sediment loads. As less sediment is deposited in the river’s delta, the plains begin to sink. One projection estimates future subsidence of as much as one foot by 2050.12Chandrashekhar, Vaishnavi Communities within the Ganges River Delta will then certainly be forced to adapt or risk becoming displaced.

Reservoir still full with winter’s monsoon rains

What can be done?

In 2017, the Ganges River fought to be designated a river with “personhood,” i.e., given the same rights as other living entities. [See our NextGen blog on other rivers with environmental personhood] This push for the Ganges’ “rights” allowed local governments to tackle the river’s extreme levels of pollution, a hazard that has very visible and acute effects on the surrounding exposed environments and communities.

The effects of climate change, however, are sometimes much less obvious in the short-term, and therefore much harder to address. Nevertheless, the dangers posed by climate change are imminent and very real. It will take global recognition of India’s vulnerability to counter the impacts of climate change on the Himalayas, droughts, and sea level changes on the Ganges Delta.

This past week on Earth Day, governments around the world acknowledging the existence of climate change and announcing plans to mitigate its effects. This included the United States, one of the largest polluters alongside China and increasingly India. It’s essential that the largest global polluters follow through on these mitigating plans; acknowledge the adverse impacts their emissions have on vulnerable populations worldwide; and treat climate change like the existential threat it is.

Men sitting on the ghat under cloth tent overlooking the Ganges


Amrith, Sunil. “Pollution in India Could Reshape Monsoons.” The Atlantic, January 21, 2019. Accessed on April 22, 2021 by JM.

Chandrashekhar, Vaishnavi. “As the Monsoon and Climate Shift, India Faces Worsening Floods.” Yale Environment 360, September 17, 2019. Accessed on April 22, 2021 by JM.

Chandrashekhar, Vaishnavi. “As World’s Deltas Sink, Rising Seas Are Far from Only Culprit.” Yale Environment 360, January 13, 2021. Accessed on April 22, 2021 by JM.

“Ganga.” Rally for Rivers, n.d. Accessed on April 22, 2021 by JM.

“Ganges River Basin.” National Geographic Society, October 1, 2019. Accessed on April 22, 2021 by JM.

Higgins, Stephanie A., et al. “River Linking in India: Downstream Impacts on Water Discharge and Suspended Sediment Transport to Deltas.” Elementa: Science of the Anthropocene, February 28, 2018. Accessed on April 26, 2021 by JM.

“Overview of the Ganges River Basin.” No Water, No Life, January 2017. Accessed on April 22, 2021 by JM.

Sehgal, Jasvinder. “Ganges Under Threat from Climate Change.” Deutsche Welle, October 24, 2017. Accessed on April 22, 2021 by JM.

Varma, GBSNP. “Ganges-Brahmaputra-Meghna delta in peril due to sea-level rise, says study.” Mongabay, March 13, 2020. Accessed on April 22, 2021 by JM.

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