Wetlands as game-changers for climate change mitigation and adaptation

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This article was co-written by members of MYRIAD-EU from CICERO (Anne Sophie Daloz, Lin Ma and Miriam Stackpole Dahl) and Wetlands International Europe (Michelle Zheng and Lea Appulo).

Climate change, multi-hazard and degradation of ecosystems are interdependent and interconnected. Fighting against environmental hazards and restoring ecosystems require increased coherency between research framework, policy agenda and local implementation. 2023 bears witness to multiple extreme hazard events around the world (e.g., extreme heat waves followed by wildfire in Southern Europe, unprecedented floods followed by a period of drought in Northern Italy, etc.). These events have disastrous consequences and highlight the need for a systemic approach to multi-risk reduction.

This article will focus on the role of ecosystems in Climate Change Adaptation (CCA) and Disaster Risk Reduction (DRR), highlighting the potential of Nature-based Solutions (NbS) to reduce the severity of multi-hazard events. The International Union for Conservation of Nature defines NbS as “actions to protect, sustainably manage and restore natural or modified ecosystems that address societal challenges effectively and adaptively, simultaneously providing human wellbeing and biodiversity benefits” (IUCN, 2023).

Employing wetlands as natural solutions for DRR alone or integrating them with traditional “hard” infrastructure can mitigate hazards (e.g., droughts, floods and storm surges) and increase the resilience of local communities and populations living in proximity to the coastal zones or river basins (Ramsar Convention on Wetlands, 2017). Despite their key role in DRR, wetlands, the most economically valuable and among the most biodiverse ecosystems in the world, are disappearing three times faster than forests. The decline and degradation of wetlands have severe consequences for our future, unless urgent actions are taken to ensure their survival (Ramsar Convention on Wetlands, 2018).

Wetlands are natural water ecosystems, which can help to mitigate the physical impacts of multi-hazard. The functions healthy wetlands provide include improving absorption capacity of floodplains during peak flows, managing runoffs and bank flows and enhancing the hydrological connectivity between river channel and floodplains. Figure 1 illustrates how wetlands can address drivers of multi-hazard risks. For example, inland wetlands (e.g., lakes, ponds and marshes) retain water during floods and release it gradually, regulating water flows and maintaining water level to prevent drought Coastal wetlands such as mangroves provide spawning and feeding grounds for fish, providing food and livelihoods; they also act as buffers against storm surges. Healthy peatlands store carbon and thereby mitigate the impacts of climate change. However, the value of wetlands in countering disasters is seldom understood, and they are too rarely considered in CCA and DRR policies and programmes.

Figure 1. Potential functions provided by healthy wetlands. Source: Wetlands International, 2018

Despite the high potential of wetlands, these ecosystems have been overlooked and continue to degrade across the world. For instance, drained peatlands, a type of terrestrial wetland ecosystem, are fire prone; large-scale drainage of peatlands can result in multiple wildfire events, consequently destroying millions of hectares of land and impacting the health of people and the local economy. Drained peatlands lose their capacity to accumulate and store water and consequently reduce flood and drought resistance of large areas, ecosystems, communities and species. Loss of peat soil due to oxidation and fire results in subsidence of the peatland surface. In coastal lowlands, this loss brings the land surface down to sea or river level, leading to frequent or even permanent flooding and loss of productivity. As shown in Figure 2, 20% of the world’s wetlands have been destroyed since 1700. Urgent actions are needed to restore and rewet wetlands. 

Figure 2: Spatial map showing the percentage of Wetlands being destroyed globally since 1700. Source: Peatland Atlas, 2023

Fully rewetted peatlands have the potential to act as natural carbon sinks, saving peat carbon stocks and reducing GHG emissions from large-scale peat extraction. Rewetted peatlands can also introduce sustainable and productive agricultural practices, such as paludiculture, which improves regional water availability and creates a new alternative business model for farmers (Wetlands International Europe, 2022). At COP26, the Nordic Council of Ministers also highlighted best practices of natural carbon sinks, such as peatlands, and their contributions to climate change mitigation and biodiversity preservation (Nordic Co-operation, 2021).

While the sustainable management and restoration of wetlands can build resilience against multi-hazard, healthy wetlands should complement other DRR measures such as early warning system, evacuation and contingency planning.

Recommendations for decision-makers:

  • Accounting for the delimitation of an ecosystem’s hydrological and ecological functioning in terms of DRR challenges;
  • Setting goals for wetland protection and restoration with relevant stakeholders/actors;
  • Recognising wetland ecosystem functions to protect against multi-hazard events in local and regional legislative framework;
  • Bridging the policy-practice-science gap to understand and reinforce NbS as adaptive solutions.
Case study: Natural sponges to reduce drought and flood risk, Germany

In mid-July 2021, close to the German-Belgian border, normally tranquil streams transformed into violent torrents due to record rainfall. The destruction left more than 220 people dead. It was one of Germany’s worst flood disasters ever and the most expensive natural disaster to date estimated at €35 billion. One year later it’s clear that land use played a significant role in the severity and investing upstream in nature-based solutions can help defend against future floods.

Most analyses of the event have focused on the unprecedented amount of rain, blaming climate change and the failure of the early warning system. While the downpour was unprecedented and climate change is likely to make such events more frequent, our decade of research with partners WWF Netherlands and Bureau Stroming in the region shows that land use was the overlooked contributor to the severity of the floods.

This region of the German Middle Mountains normally receives relatively large amounts of precipitation, making it important for water retention. But changes in land use have destroyed the natural water retention features of the landscape. We found that drainage channels, hard surfaces and bare soils that moved water quickly downstream were major contributors to the floods. Solutions therefore need to focus on restoring the absorptive capacity of these upstream sponges to store more water and slow down the release – rather than pouring more concrete to channel water or focusing on downstream measures. (Wetlands International Europe, 2022).


Conclusion: Need for a systemic approach towards DRR

The capacity of wetlands to help mitigate multi-hazard events and reduce disaster risk can depend on local geographical conditions and socio-political contexts. Policy-makers and decision-makers should consider a systemic approach to DRR, which is a part of the work in MYRIAD-EU. Through the MYRIAD-EU project new methods and approaches are explored that focus on incorporating NbS and addressing multi-hazard risks in tandem with each other. MYRIAD-EU contributes to the improvement of CCA and DRR plans by working on Dynamic Policy Adaptive Pathways (DAPP-MR, 2023) where we review existing and new adaptation solutions across hazards and sectors in five pilot studies (MYRIAD-EU, 2023).