Rising Tides, Falling Freshwater: The Saltwater Intrusion Crisis

In South Africa, saltwater contribution to groundwater percentages range from 0.01 to forty-three percent, while in places like Somalia, the percentages exist at high levels, with around fifty percent of the population exposed to unsafe salinity levels, the waters of for example the Lagos harbor in Nigeria having a salinity variation of thirty percent.

In Vietnam, saltwater intrusion in the Mekong Delta reached about 110 kilometers inland in 2019-2020, 10 kilometers deeper than average, while the Chao Phraya Estuary in central Thailand, home to Bangkok's 14 million people, shows vulnerability to saltwater intrusion, just like the Indian subcontinent, which has a coastline of about 7,500 kilometers.

In South America, saltwater intrusion affects the Valdivia river in Chile, while the average salinity of the Sao Francisco river in Brazil increased by about 20 percent with the construction of a dam, with a model of Partido de la Costa in Argentina showing that saltwater intrusion could take place over 25 to 40 meters.

Saltwater intrusion is not confined to these areas, since it has assumed a global dimension, with the average rate of sea level rise in northeast United States put at three millimeters per year, and more than 15 percent of the coastline in the contiguous United States having groundwater levels at sea level, while a study stated that 41 nations have at least one coastal segment at the risk of saltwater intrusion.

Since 1880, saltwater moved into low-lying areas due to among other factors global warming, with the rate of sea level rise having reached eight to nine inches, the rate of sea level rise in the twentieth century hitting 1.5 millimeters per year, and the rate of increase predicted to accelerate in the twenty-first century.

Since 2000, the number and duration of droughts have increased by 29 percent, large areas in Ethiopia, Kenya, and Somalia affected by the event, which displaced an estimated 2.4 million people in the Horn of Africa, with South Africa experiencing the phenomenon from for sometime.

Since 2021, central Asia have been experiencing one of the most severe droughts in the past 40 years, about 42.57 percent of the region challenged by record-breaking water scarcity conditions, while nearly 30 percent of mainland southeast Asia suffers from a drought that lasted five months, Cambodia's average duration at the period reaching almost six months.

In 2023, the world recorded 45 hurricanes, up from 40 in the year before, with 72 percent of storms forming in the northern hemisphere, 28 percent of them forming in the southern hemisphere, 1992 and 2018 tied as the most active years, each recording 59 hurricanes.

Unfortunately, with sea level rise, saltwater makes an incursion into groundwater, the same thing happening with hurricanes, while land rises through drought allow for the entrance of saltwater.

Saltwater intrusion into groundwater can change the situation with coastal ecosystems, as it leads to the loss of biodiversity, a critical condition, with 75 percent of the world's species slated to go extinct by 2050, one million species facing extinction, including 40 percent of amphibian species, 33 percent of reef-building corals, and 30 percent conifer trees.

Saltwater intrusion into groundwater can change the dynamics with coastal communities, as it accelerates the contamination of freshwater sources, a critical situation today, seen within the context of 16 species having been declared extinct in 2020, 80 of the world’s freshwater fish species having already been declared extinct, and the number of mega-fish having declined by 94 percent since 1970.

Saltwater intrusion into groundwater can change the situation with freshwater plants, leading to the shrinkage or death of species, a critical situation in some parts of the world today, seen within the context of 571 plant species having gone extinct in the last 250 years, and the fact that 39.4 percent of the world's plants face the threat of extinction.

In other words, since saltwater intrusion worsens the situation with plants, fish species, and animals, it could worsen climate change, as animal and plant species play a major part in ensuring balance in the ecosystem.

To prevent a worsening of the situation, nations must learn to maintain natural vegetation and dunes along coastlines to act as barriers against saltwater intrusion, as well as restore wetlands and mangroves, which can help filter out saltwater and maintain groundwater quality.

What to Eat

Vegan food from Vietnam, Credit, Holidify.com.