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This article was co-written by Frédéric Thomas (CNRS, laboratoire MIVEGEC), Thi Phuong Linh Huynh (IRD), Toan Thuy Le (CESBIO), Thi Thu Ha Nguyen (LASTA), Truong Toan Nguyen (University of Queensland), Tu Anh Nguyen (IMHEN), Frédéric Thomas (IRD), Chi Quang Truong (CTU), Quoc Thanh Vo (CTU), and Canh Toan Vu (ISET).
Vietnam is often listed as one of those countries most at risk from climate change. What would the economic and social impacts be if the global average temperature rises by? 1.5°C, 2°C or even more in the coming decades?Are local drivers of environmental change worsening these impacts? What policy and other levers could be used to adapt?
Recent temperature data for Vietnam show an accelerating warming trend in the recent decades, with an average value of ~0.2°C/decade over the last 40 years and the highest increase in the last decade. The average annual rainfall increased by 5.5% over the same period. However, there were contrasting trends depending upon where you live. In addition, sea level is rising, with an average trend of 3.6 mm/year over 1993–2018. This report has a new climate dataset that allows for more detailed evaluation. Recent climatic Trends across the Country.
Regarding future climate projections, at the end of the century, temperature is projected to increase from ~1.3°C under a scenario of low greenhouse gases global emissions (scenario RCP2.6) and to ~4.2°C under a high emissions scenario (scenario RCP8.5), with faster increases on the North of the country than in the South. The annual rainfall is also projected to rise in most regions, with a different seasonal distribution. This is due to a bias correction downscaling technique that we used for improving the spatial resolution of global climate models’ projections. This new downscaled data allows everyone to quantify changes in climate variables like temperature and precipitation over the country’s different regions.
Even though it is more difficult to reconstruct long-term climate data for Vietnam prior to the early 20th centuries, one can still use proxies or historical archives that have their own bias. But This is the embryonic environmental historyAlready, evidence shows that Vietnamese society has been living in the middle of climate change for many years. The Vietnam climate history’s early development of political structures that reflect the constant need to adapt and control natural events is especially interesting. Even if the climate issue was not the same as it is today, there were already political responses to climatic hazards that can highlight today’s climate actions as well.
At the forefront of global and local pressures
The Mekong River delta is one of the largest deltas in the world, currently home to 17 million people and supplying more than half of Vietnam’s rice production. The region is Faced with multiple threatsSome are caused by climate change, while others are the result of human activities upstream or in the delta. Global climate change will lead to rising temperatures and precipitation in the delta, just like in other regions in Vietnam. However, the delta’s very low elevation makes it a hotspot of rising sea level. The delta’s average altitude is only about 80cm above sea level. Based on the climate scenario, projections of future sea-level increases for the century range from +24 cm to +84cm. This means that large portions of the delta could sink below sea-level by 2025, or even earlier, if the worst-case scenario of polar ice-sheet collapse becomes a reality.
Laurent Weyl/Collectif argos, Fourni par l’auteur
However, the delta may drop to sea-level in the near- and mid-term due to human activities, not climate change. The delta is actually Losing elevationGlobal sea-level rise is increasing at a much faster rate than the global average. Subsidence, also known as the gradual lowering or disappearance of the land’s surface due to sediment compaction, is being driven by groundwater overextraction. In some areas, subsidence rates can exceed several centimeters per annum. The current rate of sea-level rise is about 3.6 mm/year while the rate of subsidence reaches up to 5 cm/year.
Aside from that, the delta faces Increased saline intrusionsIt is most common in the dry season and can cause problems for aquaculture and agriculture. This phenomenon is primarily driven by riverbed level erosionRiverbed erosion is caused by sediment starvation due to upstream dams and sand mines. Riverbed erosion will continue to increase in the coming decades. Greatest factorThis could lead to large increases in saline intrusions. Worst-case scenario: Salt intrusion could lead to an increase in salt intrusion of up to 40% by midcentury. This could result in a decrease in fresh water availability and a reduction of rice cropping areas during dry seasons. We found that approximately 140,000 ha (10%) would be inaccessible for rice cultivation under these extreme circumstances.
Groundwater extraction and mining are therefore the most effective mitigation measures to limit elevation loss, saline water intrusions, and other impacts in the future. On the ground however, farmers can partly adjust their techniques, but they would also face the dire necessity to switch crop or even migrate when yields become too low… In the end, adaptation strategies always combine a mix of endogenous decisions and governmental decisions that Interact and influence each others.
National socio-economic impacts
It is possible to assess the impact of climate variability at the national level on key economic and social sectors. We can see strong evidence for the effects of extreme temperatures, particularly cold and heat waves, on mortality rates over the 2000-2018 period. Climate change could also impact the incidence of many infectious diseases. But the most severe aspect of the possible impact of climate change upon Vietnamese society is the health.
It is possible that households may also be affected by the changes in their daily lives at work. We found that a day with temperatures higher than 33 Celsius degrees results in a decline of income. This was also accompanied by an increase in inequality. The Vietnam Household Living Standards Survey showed that low-income families suffered a 1.51% decrease in their income than other groups. Using the Labor Force Survey, we find that a 1°C rise in temperature leads to a 0.5% expansion in gender hourly wages gap. On the demand side of the labor market, using the Vietnam Enterprise Survey, our research shows that an increase in temperature would reduce firms’ revenue, total factor productivity, output, and size.
As the temperature rises, so does the demand for electricity in the energy sector. An increase of 1 degree Celcius would result in a rise in residential electricity consumption of about 5% and firm electricity consumption of 4%, respectively. Additionally, fossil fuels produce more pollutants. Our study examines the supply side of the equation, focusing on the hydropower industry and water flow in major river basins in Vietnam. Most climate forecasts predict that hydropower production will rise with increased precipitation. To store hydropower generation water, there will be more variability in rainfall over the year. This will require greater investment in larger water reservoirs.
These impacts on some key economic sectors of the Vietnamese economy build up an aggregate direct damage over Vietnam of ~4.5% for a 1.5°C increase in global average temperatures, and ~6.7% GDP loss for a 2°C increase in global average temperature. Economic sectors are interconnected with the rest of the world and each other, but they are not independent from one another. They interact through intermediate consumes, exports, imports, and also through financial interlinkages to the rest of world and more broadly, the decisions of financial sector. The direct damages can be plugged into a macroeconomic model (i.e. We estimated that the macroeconomic damages were 30% higher than the direct damage by plugging the direct damages into a macroeconomic model, i.e. This results shows how important it’s to not only stop at the level of the sector, but also to understand how macroeconomic connections might increase the climate impacts.
Adaptation strategies as development strategies
Local adaptation decisions are insufficient at the level of the Mekong Region. Cooperation in the management of water is crucial to regional adaptation and mitigation. Transboundary governance is essential to achieving a just transition. It must also be consistent with the general principle of water as a fundamental need and right for every Mekong citizen. The recent Mekong River Commission initiative called “proactive regional planning” could play an integrative role, via joint mitigation investment projects and adaptation measures between countries, actors, and sectors.
For decades, Vietnam has been working to improve the country’s adaptation policy framework. Significant progress has been made to increase community resilience and adaptive ability, reduce natural catastrophe risks, and limit the impact of climate change. The lack of decision-support tools and appropriate evaluations has meant that vulnerability and risk issues are not adequately addressed in climate change adaptation strategies and disaster prevention strategies. As a result, funding and international assistance are still behind.
It is important to remember that financing cannot solve all major problems. Some adaptation projects and policies don’t clearly reduce vulnerabilities or risk. As adaptation is the result complex interactions between individual choices and planned policies, so too is the complex interplay of these two factors. Climate change finance and local social dynamicsThat structure is what determines adaptation funding. People in a region such the Mekong delta have been adapting for centuries to changing conditions. This is evident in the major land-use change that has taken place over two decades.
It is therefore important to consider models and approaches that take into consideration both. Adaptation planned and spontaneousBoth can bring about major changes in system dynamics or innovation. Also, it is imperative to develop and implement comprehensive monitoring and evaluation systems for adaption and, more generally, to integrate adaptation in the entire development planning and budgeting process of the country.
Vietnam’s development strategy should include adaptation to the inevitable consequences of climate change. This is in addition to its ambitious contribution at COP26 to reducing emissions.
