A few years ago, the water in certain areas became too salty to drink. Over time, it also became unsuitable for bathing and cooking. The salinity of the water has been steadily increasing, exacerbated by the effects of climate change. This rise in salinity is impacting daily life and essential activities, highlighting the growing urgency of addressing climate-related issues and their effect on water quality.
Despite being a natural phenomenon when the freshwaters of the river mingle with the saltwater of the sea, i.e. salt wedge, the area in which saltwater has sunk through the subsoil beneath the subsoil beneath the surface of the land. However, it can spread, particularly in the summer months when there is less rain to help disperse it.
It is widely acknowledged that global sea levels have been rising, and climate change is a contributing factor.
According to different researches, for instance the one conducted by scholar Peter Scott, human-induced climate change may be a primary driver of increasing levels of saline water in our seas and oceans.
The case of Italy’s Po Delta
In the Po Delta region of northern Italy, where the Po River meets the Adriatic Sea, a select group of locals dare to brave the waters. These seasoned individuals possess a unique familiarity with the ever-changing landscape, recalling the former contours of the riverbanks and landmasses now submerged beneath the surface. Their intimate knowledge of the area’s shifting topography allows them to navigate the treacherous waters with confidence, a feat few others dare to attempt.
Delta del Po, Italy-only the locals are daring enough to venture into the waters of the Po River, where the Po Delta flows into the Adriatic Sea off the coast of northern Italy.
That is – only those among the locals who still remember the position of the river banks and lands which have long since sunk into the water.
The confluence of the Po River and the Adriatic Sea is experiencing concerning levels of saltwater encroachment, jeopardizing the delicate balance of the region’s aquatic environment.
In 2022, during an exceptionally dry summer, a salt wedge extended over 40 km (25 miles) inland from the Adriatic Sea. Last year, with increased rainfall, the salt wedge spread for 17 km (10 miles). The Po River delta spans 54 square miles between the Veneto and Emilia Romagna regions in northeast Italy, with approximately 70 percent of the area being agricultural land.
Increase in salinity
Rising water salinity is damaging coastal ecosystems and agricultural, livestock, and industrial activities, according to a recent ARPAE report. Contributing factors include climate change effects like reduced rainfall, drought, and freshwater overconsumption.
Another consequence of the rising water table, driven by accelerating sea level rise, will be the intrusion of saline water into freshwater and brackish areas. This change will impact coastal communities that rely on local freshwater sources.
For example, exacerbating these issues, the area was extensively mined for methane gas until 1961, when the Italian government ceased operations due to subsidence. In the rice fields of Porto Tolle in Veneto, areas damaged by salt seeping into the soil are clearly visible. This damage is caused by both direct irrigation with brackish water and saltwater rising from the subsoil.
In coastal communities, groundwater is essential for drinking water, public supplies, agriculture, and industry. Rising sea levels are predicted to increase groundwater salinity, potentially making some areas uninhabitable even before flooding occurs. This surge in salinity is a major concern, especially for low-income countries.
Increasing concern for the coastal regions in India
In coastal areas, groundwater is saline even at shallow depths. In Gujarat, tidal ingress affects upper aquifers and low-lying marshy lands inundated by seawater during high tides, mixing saline seawater with groundwater.
This downward seepage increases groundwater salinity. Before the monsoon, the water table lowers, creating a reverse hydraulic gradient near the coast, causing seawater to flow landward in some areas. During the monsoon season, the water table recovers, establishing a positive gradient that leads to submarine water discharge into the Arabian Sea. Therefore, rendering unusable what had been a vital part of day-to-day life.
Saltwater intrusion into vital groundwater supplies is a global climate change issue, with richer nations better equipped to adapt. It poses a greater challenge for countries like India, which is expected to surpass China as the world’s most populous nation this year. Despite its growth into one of the largest economies, India is still considered a developing nation.
As the world’s third-highest emitter of carbon dioxide, India contributes significantly to global warming. The country is increasingly focusing on a transition to clean energy, with ambitious renewable energy targets, a green hydrogen initiative for clean fuel production, and programs encouraging citizens to adopt more sustainable lifestyles.
However, transitioning to sustainable behavior will take time. In the meantime, rising sea levels, changing ocean patterns, extreme storms, overuse of wells, and overdevelopment are all exacerbating the salinity problem in coastal regions like Kochi.
This challenge is particularly severe in a country where access to freshwater is already limited. According to UNICEF, less than half of India’s population has access to clean drinking water.