Wetlands and Climate Change - Impacts and Importance

Wetlands offer essential ecosystem services that support the environment. They hold about 125,000 freshwater species. Wetlands are critical to successfully maintaining the earth, especially against climate change. They can help us change the tides of climate change worldwide. We often underestimate the role of nature in taking care of itself, especially when it is free from human interference. 

Healthy wetlands can sequester carbon in their soils and biomass. Healthy wetlands also support coastal communities and serve as nesting grounds for biodiversity. This article explores four facts about wetlands' potential to reduce and control climate change. 

Related read: Facts About the Role of Soil Health in Climate Change Mitigation. 

What are wetlands? 

Wetlands are areas that are totally or partially covered with water. They are transitional between permanently flooded deep water areas and areas with their water tables near the surface. Sometimes, shallow water covers the surface of the land. Examples of wetlands are:

• brackish marsh,
• fresh marshes,
• salt marshes,
• swamps,
• wet prairies,
• bogs,
• forested wetlands,
• and vernal pools. 

You can also refer to wetlands as areas with dominant natural water saturation levels, determining the soil development processes and the plants and animals inhabiting them. The covering of water in some wetlands could be permanent or seasonal.

Types of wetlands 

There are two types of wetlands. They are: 

Coastal Wetland 

A coastal wetland is an area of land connected to estuaries where natural freshwater mixes with the ocean's salt water, creating a new environment with varying salt levels. The constant sea level rise and saltwater make a coastal wetland difficult for plant species. 

Therefore, you will barely find vegetation in many coastal wetlands. However, some plants can withstand the conditions of a coastal wetland. There are various sub-groups of coastal wetlands. They are: 

• Coral reefs
• Marine subtidal aquatic beds, i.e., seagrass beds
• Estuarine waters
• Intertidal marshes
• Coastal freshwater lagoons
• Coastal brackish/saline lagoons
• Intertidal forested wetlands

Inland wetland

Inland wetlands develop in isolated depressions surrounded by dry land. An inland wetland's soil is very poorly drained, often found in floodplains or other areas prone to flooding. The various inland wetlands are:

• Permanent rivers/streams/creeks
• Permanent inland deltas
• Permanent freshwater lakes over 8 ha
• Permanent freshwater marshes
• Alpine wetlands
• Tundra wetlands
• Forested peatlands

4 Facts about coastal wetlands' contribution to mitigating climate change

1. Wetlands regulate, capture, and store greenhouse gases more than other natural ecosystems. 

Inland and coastal wetlands can remove carbon and other greenhouse gases from the atmosphere and transfer them into the wetlands’ soil as organic soil matter. Wetland producers remove carbon dioxide through photosynthesis². Then, they convert it into cellulose and other carbon compounds before it becomes soil organic matter. 

Wetlands are very productive ecosystems. Their plants capture carbon easily from the atmosphere and store it in their fauna. There are three steps involved in the process of a wetland’s climate change adaptation process. They are photosynthesis, sedimentation, and nutrient enrichment through external factors. Photosynthesis by the wetland plants adds organic matter to the wetland’s floor.

The sedimentation process is the process of the particles in water settling down. The native plants in wetlands do this by slowing down the water velocity and providing a surface for the suspended particles to bind, thus preventing the possibility of the particles from suspending again. 

Wetlands’ ability to capture carbon from the atmosphere also depends on the input and output of carbon. 

Carbon inputs comprise carbon dissolved and suspended in inflowing and runoff water. It also includes carbon in aging plants in wetlands. Carbon outputs include dissolved and suspended carbon in outflowing waters. Carbon outputs also include the inorganic forms of carbon released as CO₂ and CH₄ through mineralization during the decomposition of organic matter.

2. Prioritizing the protection and restoration of natural wetlands enhances carbon sequestration.

We are losing natural wetlands faster than forests in the environment. According to the Global Center on Climate Adaptation, wetlands disappear three times faster than forests. Earth has lost over a third of its wetlands since 1970. Also, about 83% of the world's wetlands plant and animal species are threatened with extinction.

Losing most of the world's wetlands is an environmental disaster because it contributes to and speeds up climate change. Draining wetlands makes them susceptible to high temperatures, fires, and drought. These extreme weather events on wetlands release carbon emissions into the atmosphere. The effects of climate change on wetlands are terrifying. 

Wetlands are biodiversity hotspots, holding up to 40% of the earth's biodiversity species. Wetland wildlife species risk extinction as their habitat becomes next to non-existent. Without wetlands, we remove their significant contribution to greenhouse gas reduction. So, what destroys wetlands and their biodiverse ecosystems? 

Human activities like farming, construction, and general human urbanization contribute to the rapid loss of wetlands. Similarly, the coastal wetland is more prone to destruction caused by natural climate events. Extreme weather events could be erosion or rising sea levels. Also, we drain coastal wetlands for agricultural activities. We mostly drain coastal wetlands for aquaculture. 

However, converting wetlands does more harm than good. For example, converting mangrove forests to shrimp ponds in Southeast Asia releases over 6 to 14 million tonnes of greenhouse gas emissions yearly. The international world must protect the surviving wetlands and restore the destroyed ones.

Restoring wetlands increases the possibility and potentiality of wetland carbon storage. The more wetlands we restore, the more we increase our chances of fighting climate change. 

3. Protecting and restoring wetlands to create effective carbon sinks offers many more benefits.

Wetlands are one of the most productive ecosystems in the environment compared to other ecosystems like rainforests and coral reefs. Wetland restoration has many other benefits besides its potential to reduce climate change. Wetland offers a variety of services for humans and wildlife.
These services are: 

• Improve water quality
• Provide wildlife habitat
• Improve water supply
• Offer flood protection 
• Reduce the damage of storm surges
• Maintain the productivity of the ecosystem

The presence of wetlands improves water quality, reducing the number of polluted water bodies in the environment. Wetlands filter sediments and absorb pollutants in surface waters. The plants growing on wetlands also cleanse the water by removing excess nutrients. This filtering function improves the groundwater quality in some urban areas.

Wetlands are home to many species of living organisms like reptiles, amphibians, birds, and mammals. 

Wetlands play an important role in the survival of migratory bird species, as they usually use wetlands as settling spots. For example, sand-hill cranes and wood ducks use marshes in the Southern U.S. during winter. Deer, bears, and elk also use wetlands for food and shelter. In addition, wetlands support fisheries.

Several freshwater and marine aquatic animals depend on wetlands for survival. Aquatic animals like trout, sunfish, crab, shrimp, croaker, striped bass, and oysters use wetlands for shelter, feeding, and breeding activities. Also, wetlands, especially coastal wetlands, offer flood protection to local communities and many species.

Weather and water

Furthermore, wetlands support storm surges and high sea levels by functioning as natural sponges. Wetland soils soak up and trap water, then slowly release surface water, groundwater, snowmelt, rain, and flood waters. In addition, trees, vegetation, and roots slow down the speed of the floodwaters and distribute them. Slowing down, redistributing, and storing floodwaters helps reduce flood heights and erosion¹.

Another benefit of wetlands is the provision of fresh water supply. Some wetlands provide a clean and bountiful supply of water. An example of this is the wetlands in Florida. The wetlands in Florida's Everglades help recharge the sole source of drinking water, the Biscayne Aquifer. The Aquifer is the sole water supply for the Miami metropolitan area.

4. Wetlands can also release carbon into the atmosphere. 

Although wetlands are important in slowing our changing climate, they can also largely contribute. The destruction caused by the loss and drainage of wetlands releases high quantities of carbon emissions. 

Draining a wetland gives way for oxygen to reach flooded organic matter. This oxidizing interaction produces tons of carbon dioxide. Wetland drainage is also dangerous because of the potential disturbance of acid-sulfate soils. Once exposed to air, these soils release large amounts of greenhouse gas emissions. 

A study on Australian melaleuca and mangrove wetlands showed that drainage turns them from carbon sinks to carbon emitters.

12 Wetlands Around the World

Wetlands are everywhere around the world except Antarctica. Some of them are:

1. The Amazon River
2. The Llanos
3. Coastal Marshes of Northern Europe
4. Nile Delta
5. Okavango Delta
6. Congo River Swamps
7. The Orinoco River delta of Venezuela   
8. The Pantonal  
9. The Rhone River Delta 
10. Everglades National Park
11. Orinoco Delta 
12. Mekong Delta 

Conclusion 

As individuals, the facts mentioned in this article give us every reason to protect wetlands. The effects of climate change are damaging to the environment at large, and wetlands are highly susceptible to its effects. However, they also have a great potential to reduce and restore the climate conditions to a better state. 

Wetlands capture and store carbon easily in high quantities. However, we have already lost a high percentage of the earth's wetlands to human activities (i.e., the construction of urban areas). Clearly, promoting the conservation and restoration of wetlands is in our best interest.