Southeast Asia and its relationship…with floods (Part 1)

At a recent Asia-Europe Foundation (ASEF) Forum held in Hanoi, Vietnam, Tim Hill selects his favourite Sustainable Development Goal. (Image credit: Asia Europe Foundation)

By TimHill, Research Director, Eco-Business Research

Vsitors to Southeast Asia are always impressed by the intensity of the monsoon rainfall. They stand by and watch as the water courses through jungle interiors and makes its way through farmland, kampongs and cities to the sea, observing the imprint the water leaves on the culture of the people.

The waterways have defined many aspects of the region, elemental as much as it is integral. The territorial waters of the Association of Southeast Asian Nations (ASEAN) occupy about three times as large an area as the land coverage. Its rivers pour out into the Pacific Ocean, the Indian Ocean, and the South China Sea.

Over the centuries, the rivers, coastlines and wetlands of the region have provided the highways, harbours, and resources that have supported the region’s growth. And to this day, nomadic sea gypsies sail around the coastlines of different countries in the region making livings from their boats.  

Southeast Asia’s close affinity to water in earlier centuries

For hundreds of years, the region has attracted traders from other parts of Asia, searching for new commodities and markets, refilling their barrels at the many different ports of call. These sea traders brought merchandise, customs, religions and different cultures to the hunter gatherers who populated the region.

The predictable monsoon winds brought them from distant shores in regular seasons over the centuries, and with them came economic and population growth. The dense jungle that formed much of the interior of Southeast Asia meant that population settlements were concentrated along the shorelines and rivers of the region which formed the highways for trade. Ancient settlements expanded, and new settlements were formed, often around the low-lying paddy fields close to the rivers. 

The evolution of society’s interaction with water in Southeast Asia (Source: Eco-Business Research, interviews)

Transformation during the 20th Century

Over time, pressure on the region’s flora and fauna began to show. The old traditions of taking only what was needed to feed the family were replaced by the hunger for natural resources and the need to accommodate the arrival of new residents.

New harbours were cut out of the protective barriers of coral reefs and mangrove. Much of the ancient forests, particularly in lowland areas, were cut down for the timber trade and to clear the land for agriculture or new commodities such as tea and rubber.

The latter part of the 20th century saw a boom in population growth and urbanisation, further concentrating people in the overcrowded cities as they moved away from the farms. By the early stages of the current century, most Southeast Asian people lived in cities rather than the rural settlements of their parents and grandparents. 

Factory jobs replaced farm labour as the main source of work. The need to house thousands of new urban migrants took precedence over planning for adequate water and sewage supplies. Unpredictable weather patterns brought simultaneous floods and droughts to areas in close proximity. Rising sea levels started to encroach on arable land and city streets.

It suddenly became clear that the islands and archipelagos of Southeast Asia would suffer disproportionately from the effects of population growth and climate change.

Compared with the rest of the region, Southeast Asia has a very large concentration of big cities located in low-elevation coast zones. This factor alone, without any change in the climate, has made it susceptible to regular damage and loss of life from flooding.

As the economies of Southeast Asia grew, the interactions of their citizens with water evolved. The more affluent cities of Singapore and Kuala Lumpur, Malaysia, have reached the ‘post-industrialisation’ phase in which they are now looking to re-establish their relationship
with water and manage the
impact of high tides and heavy precipitation in a more sustainable and proactive way.

However, some of the less affluent countries and lower-tier cities are still struggling in the initial industrialisation phase and are being forced into focusing on flood management as they grapple with the effects of climate change. And yet, the region is still lacking in any overall system for addressing the water challenges that lie ahead.

Source: Eco-Business Research, ASEANUP, Butler, R., CIA, EastWest Centre, Kelly, P.F. & McGee, T.G., McKinsey, Szudy, M.,

Impact on rural and urban areas

Climate change, and in particular, rising global temperatures are estimated to impact both sea levels and precipitation intensity. A climate model study by the Massachusetts Institute of Technology (MIT) and researchers from the Swiss Federal Institute of Technology found that with every one degree Celsius rise in temperature, the moisture-carrying capacity of the air rises by seven per cent. This means that rainfall becomes heavier and potentially more damaging. 

Sea levels are also likely to rise with global temperatures further compounding the issue. UN-Habitat, a United Nations programme promoting sustainable human settlements, describes the direct effects of a sea-level rise to include storm flooding and damage, coastal erosion, increased salinity in estuaries and coastal aquifers, rising coastal water tables and obstructed drainage.

But it also points to a number of indirect impacts such as changes to coastal eco-systems and the distribution of bottom sediment on the seabed.

Studies indicate that increases in temperature would create severe problems for tropical regions such as Southeast Asia, and the expectation is for as much as a 25 per cent increase in the rate of catastrophic precipitation.

But with the region already suffering from very high rates of rainfall and flooding, an increase of this size would have devastating consequences if governments do not take early defensive measures. 

Moreover, in a report entitled Southeast Asia and the Economics of Global Climate Stabilisation, the Asian Development Bank (ADB) concluded that Southeast Asia is particularly vulnerable if no action is taken to address climate change, and may lose up to 11 per cent of gross domestic product (GDP) by 2100.

The Organisation for Economic Cooperation and Development (OECD) estimates that some of ASEAN’s most exposed cities stand to lose more than US$2 trillion in combined assets by the 2070s, mostly through floods and rising sea levels.

Considering the weather patterns and impact of flooding already felt, these figures actually seem conservative. After all, every year, ASEAN countries are battered by flooding either through monsoon rains or typhoons, with the more severe floods affecting multiple countries at the same time, causing issues for relief work.

This opinion piece came from the Eco-Business report Flood Controls in Southeast Asia. The report looks at trends as well as the economic impact of flooding in the region, and reflects on some of the solutions that ASEAN member states are using.