Climate Change Affecting Cambodia's Tonle Sap Lake

Tonle Sap Lake is the biggest freshwater lake in Southeast Asia. Around four million Cambodians inhabit the lake’s floodplain and rely on its natural resources for their living. The region is extremely biodiverse and harbors abundant ecosystems. During monsoon season, the waters from the Mekong River and other tributaries feed the lake. This annual flood pulse is crucial for agricultural practices as well as wildlife within the basin. Yet, the Tonle Sap Lake has come under increasing pressure. Extended droughts, destructive flash floods and rapid species loss are threatening the lake’s ecosystems. Therefore, the Rosa-Luxemburg-Stiftung (RLS) and the NGO Forum on Cambodia (NGOFC) teamed up to research and address the issues impacting Tonle Sap Lake, the livelihoods of its people and its biodiversity.

Between 2021 and 2023, NGOFC and RLS funded three independent studies focusing on the effects of the climate crisis, the changes in Tonle Sap Lake tributaries as well as their influence on migration patterns. Hundreds of respondents were interviewed. The researchers conducted case studies in water- and land-based communities. Results showed that a host of factors contributed to the lake’s distress, including climate change induced heat and irregular rainfall patterns, deforestation, overfishing, urban expansion and upstream hydropower dam construction. From 2010 to 2023 the flood pulse system weakened significantly, leading to a 40 to 50 percent decrease in the lake’s volume. Income and sustenance of people living along the shores dropped dramatically as well. Many households were forced to go into debt and give up their way of life. They increasingly sent family members to urban centers to work in precarious environments, like the garment or construction industry.

NGOFC used these studies as basis for extensive advocacy work. Policy recommendation reports highlighted critical factors, such as the necessity of regrowing forest cover or integrating ecosystem services into the cost-benefit analysis of future hydropower projects. Additionally, NGOFC has organized workshops for affected communities and key stakeholders on how to mitigate and adapt to the changes affecting Tonle Sap Lake. Through launch events and social media campaigns NGOFC was able to heighten public awareness on these issues. Although much greater steps need to be taken to ensure a just socio-ecological transformation of the Tonle Sap region, this partnership between RLS and NGOFC laid a pivotal foundation for future efforts.