The inevitable is happening: The ocean is rising — and its pace is increasing. The most recent State of the Ocean Report from the United Nations Economic, Social and Economic Organization (UNESCO) verifies that the global mean sea level has increased by an average of 3.4 mm annually over the last 31 years.
The oceans, which are essential for maintaining the global climatic equilibrium, face significant threats from global warming. The State of the Ocean Report 2024 presents alarming statistics: over the past two decades, the rate at which the oceans are warming has doubled.
The Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA), which is responsible for monitoring weather, climate, and astronomical conditions in the country, reported that between now and 2100, sea level rise in the country would be at an average of 0.2 meter by the end of the 21st century.
The rise in sea levels poses a threat of displacing millions of Filipinos residing along the coastline. The country encompasses a total land area of 30 million hectares, distributed across 7,641 islands.
By the year 2050, it is projected that at least 13.6 million Filipinos will be at risk of displacement, as reported by Addressing Climate Change and Migration in Asia and the Pacific.
The report, released by the Manila-based Asian Development Bank (ADB), identifies the Philippines as “one of the most vulnerable countries to climate change.” It ranks the country fifth in terms of the number of individuals impacted by rising sea levels.
The rise in sea levels, a clear consequence of climate change, significantly affects agriculture. Its primary effect is simple: it results in the flooding of low-lying agricultural lands.
“As sea levels rise, coastlines recede, and arable land is lost to the advancing ocean,” states the climatesustainability-directory.com. “This is not just about losing space; it’s about losing generations of agricultural heritage, livelihoods, and food production capacity.”
This poses a significant challenge in the Philippines, an archipelago comprising 7,641 islands, as reported by the National Mapping and Resource Information Authority. Certain low-lying islands, whose lands are utilized for crop cultivation, may entirely disappear due to rising sea levels.
Another immediate consequence of rising sea levels in agriculture is saline intrusion, which refers to the encroachment of saline water into freshwater aquifers or surface water bodies.
As Joaquimma Anna explains in her blog: “As seawater infiltrates freshwater supplies, particularly in coastal areas, it compromises the soil and groundwater that farmers rely on for irrigation. Salinity can alter the chemical composition of the soil, disrupting nutrient uptake in crops and thereby reducing agricultural yield.”
Beans, onions, radishes, celery, and young carrots exhibit a high sensitivity to saline water. Citrus fruits such as lemons and oranges, along with apples, are also notably sensitive. Soybeans show a significant sensitivity to low salt concentrations, whereas rice, corn, potatoes, and certain grains are particularly sensitive, especially during their early growth stages.
“These crops face significant risks, while farmers may need to resort to more expensive and less sustainable practices to mitigate the implications of saline soils,” Anna points out.
This situation is quite concerning, as the Philippines ranks among the leading rice producers globally, yielding between 19 to 20 million metric tons of palay each year. Rice serves as the primary food source for Filipinos, with an average individual consuming roughly 110 to 119 kilograms of rice annually.
The level of rice consumption is one of the highest in Asia, with rice constituting approximately 34.6% of a typical Filipinos daily dietary intake, often consumed three times a day. When rice is the sole food item, an individual can consume at least 300 grams.
“We have 110 million Filipinos eating rice and at least 2,400,000 small farmers planting rice,” wrote Jose Ma. Montelibano in his Inquirer column.
In addition to their sensitivity to saline water, rice requires a substantial amount of water for optimal growth. “Water has contributed most to the growth in rice production for the past 30 years,” said the Laguna-based International Rice Research Institute (IRRI). Irrigation-farmed rice relies heavily on this vital resource.
In his book, Water: The International Crisis, author Robin Clark states that the water required to produce one ton of rice could fill between two and three Olympic-sized swimming pools. IRRI further asserts that cultivating one kilogram of rice using traditional irrigation methods consumes enough freshwater to fill 25 oil drums.
“Rising sea levels do not only threaten crops through salinity; they also disrupt freshwater resources critical for irrigation,” Anna claims. “As coastal aquifers become contaminated, farmers may find their access to freshwater dwindling.”
If this happens, most farmers will resort to monoculture, the agricultural practice of growing a single crop or plant over a large area, year after year. “Monoculture farming undermines soil health, posing long-term risks to sustainability,” Anna says. “As the pressure mounts to produce food for a growing population, the focus on short-term solutions may further jeopardize the very systems that support agriculture.”
But that’s not all. Sea-level rise amplifies the risk of coastal flooding, especially during storm surges and high tides. “This leads to waterlogging of agricultural lands, depriving plant roots of oxygen and causing crop damage or failure,” states the climatesustainability-directory.com.
The rise in sea levels poses a significant threat to mangrove ecosystems, resulting in heightened inundation, increased salinity stress, and soil erosion, which can ultimately lead to tree death and the loss of habitat.
Mangroves generate substantial quantities of organic material (leaves/detritus) that, when decomposed by microbes, nourish bacteria, fungi, and detritus-feeding invertebrates. These smaller organisms then serve as a food source for fish and crustaceans.
Among the important fish found in mangrove ecosystems are mangrove red snapper, milkfish or bangus, lapu-lapu, siganids, barracudas, sea bass, mullets, trevally, scats, slip mouth, and mudskippers.
The increase in sea levels also adversely affects coral reefs, mainly by submerging them—placing corals at depths where sunlight cannot reach, which is essential for their photosynthesis and growth.
Coral reefs and fish maintain a symbiotic relationship. Certain fish rely on coral reef ecosystems for food, shelter, nurseries, and spawning grounds. In exchange, the presence of fish benefits the coral reefs. Fish help eliminate algae from the corals, provide vital nutrients for coral development, and assist in managing pest populations.
The average diet of Filipinos consists of a combination of rice, vegetables, and fish, with fish serving as the primary source of protein.
“Fish and seafoods are the main source of good quality protein for Filipinos, thus, availability and accessibility must be ensured. If the situation persists and left unattended, this may result in higher medical costs for the management of illnesses as a resultant factor of nutrient inadequacy,” said Dr. Imelda Angeles-Agdeppa, director of Food and Nutrition Research Institute.
An estimated 10% to 15% of the total fisheries in the Philippines come from coral reefs. The fish caught from healthy reef areas range from 20-25 metric tons per square kilometer per year. About 80% to 90% of the income of small island communities come from fisheries.
There is no way the world can stop the sea level from rising. “The crux of the sea level issue is that it starts very slowly but once it gets going it is practically unstoppable,’’ said Dr. Stefan Rahmstorf, a widely recognized sea level expert from Germany. “There is no way I can see to stop this rise, even if we have gone to zero emissions.’’
By zero emissions, he was referring to greenhouse gases (GHGs) or those gases that have the property of absorbing infrared radiation emitted from Earth’s surface and reradiating it back to Earth’s surface. Examples of GHGs are carbon dioxide, methane, and surface level ozone.
“Climate change is for real,” said Rajendra K. Pachauri, the 2002 to 2015 chairman of the Intergovernmental Panel on Climate Change (IPCC) during the fourth and fifth assessment cycles. “We have just a small window of opportunity and it is closing rather rapidly. There is not a moment to lose.”
