CAN THO CITY, Vietnam – Even before the first lights flicker across the river, the day has already begun for Le Hung who sets out early in his motorised boat and fishes in one of the canals on the Mekong. By the time the father of two toddlers makes it back home with the day’s catch, it is already eight a.m.
But there is more for him to do. After breakfast, Le Hung is off to work on his family’s one-hectare rice farm on which he has planted the year’s second crop. Hung, 35, is hoping to get a good yield from his land in the flood-prone village of Khu Voc Thanh Phu. Yet while that used to be almost guaranteed in the past, that’s no longer the case these days.
Le Hung’s remote village is at the edge of a tributary in Can Tho, which lies at the centre of the Mekong Delta. Can Tho has inter-connecting rivers and canals. Yearly floods deposit large quantities of alluvia on its rice fields, helping Can Tho acquire the label ‘the green lungs of the Mekong Delta’.
The Delta itself is Vietnam’s rice bowl, an agricultural wonder that churns out nearly 40 percent of the country’s entire agricultural production from just 10 percent of its total land mass. Farmers wearing wide conical hats while bent in the fields are among the most enduring images in this part of the country that is home to about 20 million people or about a quarter of Vietnam’s population.
Farming has been the backbone of Vietnam’s economic growth and stability over the last couple of decades and the Mekong Delta is an important plank in its food programme. Rice, meanwhile, is a top crop in Vietnam, which is the second largest exporter of the commodity in the world, next only to Thailand.
But climate change is threatening Vietnam’s agricultural output, as well as all other economic activities in the country. Here at the Delta, floods during the rainy season from June to November seem to have become more devastating every year while seawater intrusion during the dry months from December to May have worsened.
Le Hung says that with Nature suddenly getting “crueler” by the year, farmers like him are sometimes left with little or no rice yield at all, which is why they have turned to fishing to augment their ever-shrinking income. Some also peddle goods in the river canals or use their boats to ferry foreign tourists who frequent the Mekong Delta to observe the people’s traditional way of life or take a tour around the picturesque canals.
There is a bigger impact, however. Anthony Oliver-Smith, author of a study on sea- level rise and the vulnerability of coastal populations, notes, “Since the Mekong Delta is the principal rice-growing area in the country, producing half of the staple food for the nation, any significant alteration in the status of these lands will have serious implications for the economy, health, and nutrition of the people of Vietnam.”
Lair of the ‘Nine Dragons’
The Mekong Delta is a flat plain with an area of more than four million hectares, of which 2.7 million or almost 70 percent are cultivated agricultural land. Formed from eroded sediments from upstream, the Delta is located in southwestern Vietnam where the Mekong River, the longest in Southeast Asia, approaches and empties into the sea through a network of tributaries. In Vietnam, it is called ‘Cuu Long’ or ‘Nine Dragons’, in honour of the nine “mouths” that it used to have.
Originating from the Tibetan highland plateau 4,200 kilometres away, the mighty river makes its way through China, Burma, Laos, Thailand, Cambodia, and southern Vietnam before flowing out into the South China Sea. Its waters begin to rise around the end of May and reach their highest point in September. Its flow ranges from 1,900 to 38,000 cubic metres per second depending on the season. Almost 500 cubic kilometers of water are discharged from the Mekong into the sea each year.
Any development upstream, such as damming and other infrastructure, affects the course or behaviour of the river as it flows downstream. In fact, experts say that upstream development and climate change have already exacerbated saltwater intrusion in the Delta during the dry season, when the flow to Tonle Sap Lake in western Cambodia reverses towards the Mekong River.
Tonle Sap in Cambodia is a shallow lake and is part of the Mekong River system. Fed by numerous streams, it is the largest lake of Southeast Asia. During the dry season, it drains by the Tonle Sap River southeast to the Mekong River. And during the wet monsoon season from June to November, the high waters of the Mekong River reverse the flow of the Tonle Sap River and increase the size of the lake from 2,600 square kilometres to 10,400 square kilometres.
When the Mekong’s high waters recede, the flow reverses. This natural phenomenon provides a unique and important balance to the Mekong River downstream of the lake, and ensures a flow of fresh water during dry season into the Mekong Delta, buffering the intrusion of salt water from the South China Sea.
In most coastal areas, salinity is high in both soil and water during the dry season. It then decreases over time after the monsoon rains have started. But the salinity comes back during the dry season when most of the fields are left barren. Only when freshwater resources are available can salt-tolerant and short-maturing crops be grown in these areas.
For wet-season rice, the main problems are encountered at the beginning of the season during crop establishment in the months from June to July, when soil salinity is still high. Because rice is highly sensitive to salt stress in its early growth stage, this poses a major problem to rice farmers because transplanted seedlings can all die, and establishing a sufficient crop stand becomes very difficult.
Salt in the earth
Both salinity and alkalinity are also encountered in some inland areas. Salt accumulation in these areas is mostly caused by improper irrigation, where oftentimes excess water is used without proper drainage.
In these areas, the challenges are even greater where salt stress persists throughout the season. Proper reclamation measures are needed to bring the soil back to productivity. This normally involves enormous investment to amend the soil and involves adding gypsum or other chemicals to free salt from alkaline and sodic soil, followed by proper flushing with fresh water and drainage.
According to a recent study by Vo Thanh Danh, dean of School of Economics and Business Administration of Can Tho University and head of Dragon Mekong Institute for Climate Change Studies, approximately 1.7 million hectares of the Vietnam Mekong Delta have already become “salinised”.
“Salinity is getting critical because of sea-level rise,” says Dr. Ngo Dang Phong, the Australian Centre for International Agricultural Research (ACIAR) project head for Climate Change Affecting Land Use in the Mekong Delta Adaptation of Rice-based Cropping Systems (CLUES) programme. At the same time, he says severe saltwater intrusion is taking place because “the window of fresh water in Vietnam is getting shorter” due to climate change, which has seen alterations in rainfall patterns and aggravates climate extremes such as drought, water scarcity, and flooding.
Annually, flooding inundates two million hectares and affects more than 11 million people in the Delta. According to Professor Danh’s study, the Delta’s terrain has limitations that results in the inundation of between 1.4 million and 1.9 million hectares of land in upstream areas, and the salination of between 1.2 and 1.6 million hectares of land along coastal areas.
“Whenever there is heavy flooding, our farm turns into a lake,” says farmer Le Hung as he tries to relax after a long day of almost-nonstop toil. “Any flood occurrence is not good to rice plantation because it reduces our production and income. That’s why I need to do many jobs to get extra money for my family.”
He puts the impact of climate change on farmers like him this way: “Our harvest is affected and reduced when the weather is bad, like when there is drought or too much rainfall.”
From bad to worse
He and other Mekong Delta farmers are in for worse, however. Observes Dr. Mukand Babel of the Asian Institute of Technology: “The Tibetan plateau has been identified as a climate system that is likely to change rapidly because of global warming. There might be less rainfall in some parts of the (Mekong Delta) basin and thus less flooding. (But) a modest 20-centimetre rise in sea levels would see salt water going 60 kilometres to 70 kilometres upstream during the dry season, affecting water and land along the riverbanks.”
“The impacts of climate change,” Babel concludes, “could be devastating for the millions of people who depend on the Mekong for their livelihoods.”
A March 2012 study by the Singapore-based Economy and Environment Programme for Southeast Asia (EEPSEA) meanwhile affirms earlier findings that Vietnam is among the top five countries most affected by climate change. It also warns that if the sea level rises by between 0.2 and 0.6 metre, up to 200,000 hectares of the country’s plains will be submerged. A metre rise means 90 percent of the Mekong Delta will be flooded.
Another EEPSEA research, “Hotspots! Mapping Climate Change Vulnerability in Southeast Asia”, meanwhile says that eight out of 10 of the provinces in Vietnam that are most vulnerable to the impacts of climate change are around the Mekong Delta.
Ben Tre province, east of Can Tho, is the most at risk, according to the mapping assessment report released in 2010. Under the worst-case scenario, 51 percent of Ben Tre’s total land area could be submerged because of rising sea levels.
This early, farmers are already losing their rice lands to the sea. In Dat Islet, which is part of Ben Tre, 53-year-old farmer Thao Le estimates that some 100 hectares have been engulfed by seawater over the years.
He also says that salination has become a serious problem in Dat Islet. Indeed, he says that he can no longer plant more than one rice crop per year on his land of less than two hectares.
Anthony Davis, an Australian married to a Vietnamese, says the rice lands in Ca Mau province are suffering the effects of saltwater intrusion as well. Ca Mau is located at the tip of the lower Mekong Delta, where fresh and seawaters meet or fuse, and it seems salinity is at its worst there.
“About 95 percent of farmers in Ca Mau gave up rice farming due to massive salt intrusion and opted to sell their lands because of salinity,” says Davis, who has a 28-hectare farm in the lower Mekong Delta. “Majority of the poor farmers lost their livelihood and rice land to seawater intrusion prompting them to shift from rice cropping to shrimp industry. This is the real situation now in Ca Mau province.”
Saved by shrimps?
He says that in order to recoup their losses in rice farming, more and more farmers in Ca Mau province are making adjustments in their traditional way of life. From rice cultivation, they are shifting to a combination of fish-shrimp-and-seaweeds husbandry where income is more rewarding. Those whose farms are beyond fixing have turned to salt production.
On average, Vietnamese rice farmers had a high yield of 7.77 tonnes per hectare. In a few cases an even higher yield of 11.5 tonnes per hectare was achieved in farmlands unaffected by salinity.
Today Davis says, “The salinity problem has reduced rice production by 20 to 30 percent per hectare but shrimp farming has doubled or even tripled the income of farmers who are (financially) capable of implementing new adaptation measures.”
But the rice farmers’ venture into shrimp farming does not seem to please government officials in Ca Mau and the military are reported to be keeping an eye on farmers moving away from rice planting.
“Shifting from rice farming to shrimp farming will cause us big trouble and even put us behind bars because the government does not allow this method as rice production is considered as (the backbone of) political and economic security of Vietnam,” says Davis.
“We could resume rice cropping during wet season as the rains and flooding help flush out salt and the seawater from our farmlands,” he adds. “But with the increasing temperature due to global warming we’re afraid that salinisation will worsen and we’re expecting less rice production in the next few years or decade.’
Yet while many see shrimp farming as a convenient fallback for families unable to use their land for rice cultivation, scientists are urging farmers to go slow in adopting the rice-shrimp system because its long-term sustainability is still unknown.
Dr. Phong, who is working on a project with the International Rice Research Institute (IRRI), for one says that the rice-shrimp system may lead to even more drastic environmental change consequences on the entire coastal belt. “Widespread adoption of shrimp farming will also change the socio-economic structure of the rural communities,” he says.
Flood- and salinity-resilient rice
To address the impact of sea-level rise and salinity on food sufficiency in Vietnam, a pool of scientists from IRRI, the premiere rice institute based in the Philippines, embarked on a study to improve resilience in rice production. Funded by the Australian Centre for International Agricultural Research, the project hopes to develop and propagate rice varieties suitable for areas that are prone to salinity and submergence.
The project, hosted in Vietnam by Can Tho University, aims to develop integrated soil, crop, nutrient and water management options that will mitigate the effects of salinity and identify factors that determine the capacity of farmers in the Mekong Delta to adapt to climate change. It is currently being implemented in An Giang, Hau Giang, and Bac Lieu provinces and in Can Tho City. Begun in March 2011, it will run until February 2014.
Project Head Dr. Phong says new rice varieties that are highly tolerant to salinity have been introduced in Vietnam, adding that these varieties can be harvested after 100 to 120 days.
Still, the Vietnamese scientist believes that even with what looks to be a success in producing saltwater-resilient grains, there is need for other adaptation measures, like setting up the proper infrastructure, to protect vulnerable areas in the delta from salinity. For Phong, the situation calls for the construction of sluice infrastructure and dykes.
As luck would have it, these are already among the interventions the Vietnamese government is resorting to in its bid to lessen the impact of sea level rise, salinity, and flooding in the delta.
To safeguard its agriculture-based economy, the government in 2009 launched a $1.0 billion, 10-year sea dike upgrade and sluice construction programme. Primarily designed to prevent saltwater intrusion into farming lands, the three-phase programme calls for the planting of mangrove forests parallel to the sea dyke system, the upgrade and construction of a dyke system alongside the road network, and the building of a sluice system.
Professor Vo Thanh Danh’s study, though, says the government’s plan to construct a concrete sea dike system in the Mekong Delta is the subject of an ongoing policy debate. Among other things, critics are wary about the effectiveness of the project, even as they complain about what they say is its hefty price tag.
Growing mangrove forests for protection
Still on track, however, is the mangrove-forest component of the project. Dr Klaus Schmitt, chief technical advisor of a German government-funded mangrove rehabilitation project in Soc Trang province, says mangroves have proven useful in protecting Vietnam’s coastline against storm surges and floods. Research has shown that a 1.5 km-wide belt of six-year-old mangroves reduced the height of incoming waves from one metre to five centimetres at the coastline.
Mangroves protect beaches and coastlines from waves and floods, reduce soil erosion, stabilise soil by trapping sediments, and absorb carbon dioxide, Schmitt says. “Mangrove forests can act as bio-shields for the protection of people and assets from erosion and storms,” he continues.
But Schmitt says that the lack of an integrated approach to sustainable management, utilisation, and protection of coastal zones has led to the unsustainable use of natural resources in those areas, thus threatening the protection function of the mangrove forest belts. The rush towards shrimp farming has also contributed to mangroves loss.
Quoting a study by the Ho Chi Minh City’s Southern Institute of Forest Inventory, the German expert says the mangrove area in Vietnam has declined to 155,290 hectares in 2000 from 408,500 hectares in 1948. But thanks to the massive rehabilitation efforts initiated by the German Federal Ministry of Economic Cooperation and Development, the area planted to mangroves has increased to 209,740 hectares in 2010.
Schmitt says the German government-funded project in Soc Trang hopes to provide solutions to address the conflict between economic development and sustainable management of natural resources and put in place strategies that can increase the viability of mangroves by enhancing their resilience to climate change.
But he stresses, “In addition to these, it is also important to understand the complex and dynamic nature of natural processes that influence the coast of the Mekong Delta and use them rather than fight them when looking for solutions of environmental problems.”
“Things which happen far away do also influence the coast of the Mekong Delta,” points out Schmitt. “For example hydropower dams in the catchment area of the Mekong River change the sediment load of the Mekong, which in turn will influence accretion and erosion along the coast of the Mekong Delta. The future of the coast of the Mekong Delta depends on how man deals with challenges this area is facing.”
[Rhaydz B. Barcia is a correspondent for the Manila Times newspaper. She is based in Albay province, which is in southern part of the Philippines’ main island, Luzon.]