The World Wetland’s Day was celebrated all around the world on the 2 nd of February under the theme “Protecting wetlands for our common future”, highlighting how our common future is closely correlated with wetlands. As a student coming from Colombo, it is with humble pride that I share the fact that Colombo is the one and only capital in the world with an urban wetland eco-system; hence bearing the title “Wetland Capital”. Yet, Colombo’s wetlands are not just patches of lush greenery, they are the unsung climate warriors of Colombo, controlling floods, reducing the urban heat while preserving biodiversity. However, these ecological wonders are under constant threat due to encroachment and inadequate conservation measures.
But how exactly do these wetlands help with climate resilience? And how does conservation of these wetlands determine Colombo’s future? This article explores how protecting wetlands is not a mere ecological conservation project but a strategic measure to combat the effects of climate change, given the global climate crisis.
Wetlands as climate warriors
As mentioned, wetlands are in the forefront of battling the effects of climate change in urban settings. As a result of the uneven conditions of the global climate, unexpected rainfalls as well as heatwaves are becoming more common at present. These ecosystems that are scattered across our capital are the reason for Colombo’s effective flood resilience. Moreover, they act as carbon sinks while reducing the excess heat in the environment. But how so?
Colombo’s Natural Flood barrier
It is not news to anyone that Colombo, due to its location in the wet zone, is at the heart of receiving rainfall in the island. Not only the South-west monsoons, but also North-eastern monsoons, cyclones and convectional rains provide the city with an immense amount of rainfall. Although it creates a positive environment for the farmers, the city faces massive flooding hazards. It is under these circumstances that our silent guardian Wetlands, comes to the scene. Wetlands act as a natural sponge that absorbs the excessive flood water and stores them in the wetland basins reducing the severe effects of it. This is known as the “Floodwater Retention”. Excessive floodwater from buildings, pavements and streets in urban areas are collected and slowly distributed to the outlets such as streams, trees and root systems, preventing a massive disturbance (U.S. Environmental Protection Agency, n.d.). Statistically, studies shows that 40% of Colombo’s floodwater are being absorbed by wetlands (BBC Future, 2024)
City’s Natural Air Conditioner
The Urban Heat Island (UHI) effect is a phenomenon where the cities become significantly warmer in comparison to its surrounding villages or natural environments due to its availability of roads, buildings and other infrastructure that absorbs heat. However, a person walking through the Beddagana wetland park or Diyasaru park might experience fresh air and a cool breeze though they are located in the middle of Colombo. This brings the focus to another wonderful task fulfilled by the wetland ecosystem in regard to climate resilience, which is bringing down the urban temperature levels and improving the air quality. Research conducted on wetlands and its effects on the atmosphere shows that wetlands help to cool the air by 1-3 0C, effectively bringing down the urban temperature levels (Zhang et al., 2022). Due to the high specific heat capacity of water, these urban wetlands absorb the surrounding heat during the daytime and release it moderately in urban areas. As I was conducting the research, the surrounding air of the wetland felt much cooler during the day while it was significantly warmer at night, furthermore, proving the functionality of wetlands as Colombo’s natural air conditioner.
Effective Carbon Sinks
It is a well-known fact that the presence of Green House Gases (GHG), especially carbon dioxide, is the major contributor towards global warming, hence being a catalyst towards climate change. Given the circumstances, wetlands play a key role in carbon sequestration by capturing and storing carbon dioxide from the atmosphere. According to the United Nation’s Environmental Program (UNEP), a single hectare of wetland can store as much carbon as an entire forest, making wetlands one of the forefront warriors in combatting climate change. Moreover, the RAMSAR convention states that wetlands store around 30% of land-based carbon which is double the amount stored by the world’s forests. It has been identified that Colombo’s freshwater wetlands in kolonnawa holds about 04 ± 14 tons of carbon per hectare, while the Thalawathugoda wetland park contains about 550 ± 23 tons of carbon per hectare up to a depth of 60 cm (Dayathilake et al., 2021).
Growing and Prevailing Threats to the Urban Wetlands
Although the wetland ecosystem voluntarily fights against climate resilience, these ecosystems are under constant threat of pollution, land reclamation, sewage and industrial waste disposal, invasive species and lack of awareness.
Nature’s Lifeline to Dumping Grounds
Despite being a fully functional ecosystem, urban wetlands also face the common enemy to any green space, pollution. This pollution is both solid waste as well as liquid waste from neighboring settlements and industrial buildings. For instance, one might get to witness enough plastic bottles and polythene wrappings scattered around these wetlands; especially in Beddagana wetland park. As for my observations, these pollutants are partly direct waste from the people who visit the wetland park and others have been floated in through various streams and canals. This brings out the critical vulnerability of wetlands due to both direct and indirect human intervention.
It must also be mentioned that a significant population of otters identifies these wetlands (especially Beddagana wetland park and Thalawathugoda wetlands) as their habitat. According to the conservationists, these otters only live in clean water and once the water is polluted, they immediately evacuate. Although the presence of otters acts as a natural indicator of wetland water quality, the park officials mentioned that there have been a significant less sighting of otters over the past few years, alarming a red light towards the wetland water quality. Additionally, the "Metro Colombo Urban Wetland Status Report" from May 2024 indicates that 64% of Colombo's wetland areas suffer from poor or very poor water quality, emphasizing the ongoing threat to these ecosystems.
Nature Against Nature
It should be noted that humans are not responsible for all the threats towards the wetlands. Invasive species and plants can be identified as nature’s own battle with itself for existence. A preliminary study published on Thalangama Wetlands identified several invasive plants threatening the biodiversity of wetlands. Notably, Annona glabra (pond apple), Salvinia spp., and Eichhornia crassipes (water hyacinth) were found to be prevalent (Rathnayake et al., 2025). One must argue that these plant species do no harm for the ecosystem as it appears lush and green by the look of it. But that itself is the problem. These invasive species (mostly aquatic plants) grow on water bodies forming a thick layer, blocking the sunlight and preventing other species such as birds from interacting with the water bodies. It is needless to mention that these plants not only destroy the biodiversity of such water bodies, but also disturbs the food chain and over time, turns the water bodies into lifeless basins of water.
Gaps In Public Awareness
Although Colombo ranks as the only wetland capital in the world, at least 2/3 of the population or more is unaware of it. Also, it is unfortunate to admit that not even a fraction of Colombo's or perhaps Sri Lanka’s population is aware of the existence of these urban wetland ecosystems. In such circumstances, the threats towards these green spaces progressively magnify, making them more and more vulnerable towards destruction. It can also be noted that school curriculum does not provide students with adequate knowledge regarding these urban wetland ecosystems and although it enlightens students with basics, it is surely not thought provoking enough for students to understand the importance of conserving these spaces. Therefore, such unawareness makes conserving urban wetlands a challenging task as people contribute towards destruction through pollution, encroachment and lack of their contribution towards conservation.
The Way Forward: How We Can Save Our Wetlands
Stronger Laws; Smarter Cities
Addressing the importance of stronger policies and laws in conservation of these ecosystems has become a timely requirement, especially in a situation where the National Wetland Policy and Strategy fulfils 20 years since its enactment. The policy has identified wetland sites of Sri Lanka, and they are protected under not only one particular law but a legal framework. In such a context, one might argue that Sri Lanka already has enough legal capacity to conserve and protect wetlands, which is not entirely a false assumption. However, there are always loopholes and overlooked aspects in the system, making it the high time to review the national policy on wetlands. As my focus is on Urban Wetland Ecosystems, it was to be noted that this specific aspect faces a lot of challenges. An Urban Development official from the Kotte municipal council stated in a panel discussion that the land of the wetland, the wildlife and the flora of the wetland region falls under three different institutions highlighting the challenge of having to work with multiple institutions in conservation needs. This brings out the lack of efficiency in the system in conservation efforts. Moreover, A renowned environmental lawyer stated that the institutions that should be taking actions towards conservation are not strong enough to do so as they lack resources for it. He furthermore stated that lack of human resources, lack of funds and moral issues of the officials have largely contributed to the loopholes in the conservation efforts and the enactment of law in necessity. Therefore, it can be suggested that the government and the relevant authorities should put their special focus into these areas.
Another important aspect that has been overlooked in the National Wetland Policy and Strategy of Sri Lanka is the climate resilient aspect of wetlands. It can be noted that all the wetlands have been protected under the conservation laws and policies that are mainly related to its biodiversity and the ecological value. However, it can be highlighted that through identification of wetlands as forefront warriors of climate resilience, not only can it be given much importance, but it can also strengthen the conservation needs and the conservation value of wetland ecosystems. Moreover, integrating these aspects into urban planning, especially acknowledging the urban wetland system in Colombo urban plan will ensure the sustainability of these invaluable ecosystems.
What Can You Do?
The Article 28(f) of the Constitution of Sri Lanka states that “every person in Sri Lanka also has the duty to protect nature and conserve its riches” ensuring your right to protect the natural environment (including wetlands) as a citizen of Sri Lanka. As it falls as not only a right but also a duty, there is indeed a lot you can do. As you have read this article so far and have gained enough knowledge about urban wetlands, you are already provided with enough knowledge and a constitutional right to protect these silent fighters of climate resilience. You can start by educating your family, friends and peers or you can start your own awareness initiatives with the help of relevant organizations and authorities. Moreover, you can support conservation projects, reduce waste and educate others about the importance of it. Therefore, next time you visit a wetland park, don’t just enjoy the view but remind yourself that you are also a proud protector of it.
Conclusion
Colombo’s urban wetlands are more than just ecosystems; they are nature’s frontline defence against climate change. As carbon sinks, natural flood barriers, and temperature regulators, they play a vital role in keeping the city habitable in an era of rising temperatures and extreme weather.
Protecting these ecosystems is not just an environmental necessity but a strategic move toward a climate-resilient future. Stronger policy enforcement, sustainable urban planning, and greater community awareness are essential to safeguarding these natural assets. Every individual, from policymakers to local residents, has a role to play in ensuring their survival.
If we fail to act now, Colombo risks losing not only its wetlands but also its natural shield against climate change. But if we choose conservation over destruction, these wetlands can continue to protect us, just as they always have. Therefore, it is high time to raise the question; will we let them disappear, or will we fight for their survival?
References
1. U.S. Environmental Protection Agency. (n.d.). Incorporating wetland restoration and protection into planning documents. U.S. Environmental Protection Agency. https://www.epa.gov/wetlands/incorporating-wetland-restoration-and-protection-planning-documents
2. BBC Future. (2024, September 17). How Sri Lanka is cleaning up wastelands and reviving Colombo’s wetlands. BBC Future. https://www.bbc.com/future/article/20240917-how-sri-lanka-is-cleaning-up-wastelands-and-reviving-colombos-wetlands
3. Zhang, Z., Chen, F., Barlage, M., Bortolotti, L. E., Famiglietti, J., Li, Z., Ma, X., & Li, Y. (2022). Cooling effects revealed by modelling of wetlands and land-atmosphere interactions. Water Resources Research, 58(2), e2021WR030573. https://doi.org/10.1029/2021WR030573
4. Dayathilake, D. D. T. L., Lokupitiya, E., & Wijeratne, V. P. I. S. (2021). Estimation of soil carbon stocks of urban freshwater wetlands in the Colombo Ramsar Wetland City and their potential role in climate change mitigation. Wetlands, 41(29). https://doi.org/10.1007/s13157-021-01424-7
5. Biodiversity Secretariat, Ministry of Environment and Wildlife Resources, Central Environment Authority, Department of Wildlife Conservation, Urban Development Authority, Sri Lanka Land Development Corporation, Field Ornithology Group of Sri Lanka, International Water Management Institute, & Cobra Collective. (2024). Colombo wetland management framework (draft).
6. Rathnayake, W., Disanayaka, H., & Batugedara, I. (2025). Preliminary study on community insights and participation dynamics in Thalangama Wetland, Colombo. ResearchGate. https://www.researchgate.net/publication/388556123_Preliminary_study_on_community_insights_and_participation_dynamics_in_Thalangama_Wetland_Colombo
7. Ministry of Environment & Central Environmental Authority. (2006, October). National wetland policy and strategy. Central Environmental Authority. 8. The Democratic Socialist Republic of Sri Lanka. (1978). The Constitution of the Democratic Socialist Republic of Sri Lanka. https://www.parliament.lk/files/pdf/constitution.pdf
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