Wetland restoration involves restoring a wetlands natural biological, geological, and chemical functions through re-establishment or rehabilitation. It has also been proposed as a potential climate change mitigation strategy. Wetland soil, particularly in coastal wetlands such as mangroves, sea grasses, and salt marshes, is an important carbon reservoir; 20–30% of the worlds soil carbon is found in wetlands, while only 5–8% of the world's land is composed of wetlands. Studies have shown that restored wetlands can become productive  sinks and many restoration projects have been enacted in the US and around the world. Aside from climate benefits, wetland restoration and conservation can help preserve biodiversity, improve water quality, and aid with flood control.
The plants that make up wetlands absorb carbon dioxide (CO) from the atmosphere and convert it into organic matter. The waterlogged nature of the soil slows down the decomposition of organic material, leading to the accumulation of carbon-rich peat, acting as a long-term carbon sink. Additionally, anaerobic conditions in waterlogged soils hinder the complete breakdown of organic matter, promoting the conversion of carbon into more stable forms.
As with forests, for the sequestration process to succeed, the wetland must remain undisturbed. If it is disturbed somehow, the carbon stored in the plants and sediments will be released back into the atmosphere and the ecosystem will no longer function as a carbon sink. Additionally, some wetlands can release non- greenhouse gases, such as methane and nitrous oxide which could offset potential climate benefits. The amounts of carbon sequestered via blue carbon by wetlands can also be difficult to measure.
Wetlands are created when water overflows into heavily vegetated soil causing plants to adapt to a flooded ecosystem. Wetlands can occur in three different regions. Marine wetlands are found in shallow coastal areas, tidal wetlands are also coastal but are found farther inland, and non-tidal wetlands are found inland and have no effects from tides. Wetland soil is an important carbon sink; 14.5% of the worlds soil carbon is found in wetlands, while only 5.5% of the worlds land is composed of wetlands. Not only are wetlands a great carbon sink, they have many other benefits like collecting floodwater, filtering air and water pollutants, and creating a home for numerous birds, fish, insects, and plants.
Climate change could alter soil carbon storage changing it from a sink to a source. With rising temperatures comes an increase in greenhouse gasses from wetlands especially locations with permafrost. When this permafrost melts it increases the available oxygen and water in the soil. Because of this, bacteria in the soil would create large amounts of carbon dioxide and methane to be released into the atmosphere.
The link between climate change and wetlands is still not fully known. It is also not clear how restored wetlands manage carbon while still being a contributing source of methane. However, preserving these areas would help prevent further release of carbon into the atmosphere.