"WETLAND AND CLIMATE CHANGE"
Wetlands are broadly deﬁned as a ‘variety of shallow water bodies and high groundwater environments that are characterized by permanent or temporary inundation, soils with hydric properties, and plants and animals that have adapted to life in saturated conditions’ (Lewis, 1995). Generally, two types of wetland deﬁnitions are in vogue, one which looks wetlands as ecotones, i.e. transition zone between terrestrial and aquatic ecosystems and the other which treats whole water body as a wetland keeping in view management perspectives.
Two of the most commonly used deﬁnitions are as under:
- US Fish and Wildlife Service (Cowardin et al.,1979)
“Wetlands are lands transitional between terrestrial and aquatic systems where the water table is usually at or near the surface or the land is covered by shallow water level. For purposes of this classiﬁcation, wetlands must have one or more of the following three attributes: 1) at least periodically, the land supports predominantly hydrophytes; 2) the substrate is predominantly undrained hydric soil; and 3) the substrate is nonsoil and is saturated with water or covered by shallow water level at some time during the growing season of each year”.
- Ramsar Convention (1971, 2013)
“Submerged or water saturated lands, both natural and man made,permanentortemporary,withwaterthatisstaticor ﬂowing, fresh, brackish or salt, including areas of marinewater the depth of which at low tide does not exceed 6 meters”.(www.ramsar.org).
Article 2.1 further provides that wetlands ‘may incorporate riparian and coastal zones adjacent to the wetlands, and islands or bodies of marine water deeper than six meters at low tide lying within the wetlands’.
Wetland and Climate Change
Wetlands help to combat Climate Change. But if these ecosystems are not protected, they could release huge amounts of greenhouse gases into the atmosphere.
Wetlands provide resilience to the harmful effects of climate change.
Wetlands lessen the impact of extreme weather events due to climate change:
- Wetlands are crucial freshwater reservoirs in regions where climate change increases drought. These responses are very often more sustainable and cost-effective than traditional engineering approaches.
- Healthy wetlands absorb floods, decreasing the incidence and severity of catastrophic flooding.
Improved wetlands management is a means of naturally combating the climate change. Rehabilitation of wetlands can significantly mitigate CO2 emissions from existing degraded wetlands. Interesting facts about wetlands and carbon storage: Wetlands only cover about 6 % of the Earth´s surface, but contain about 35 % of global terrestrial carbon. Investments in reducing carbon emissions from wetlands can be up to 100 times more cost effective than for other mitigation options.
Impacts of Climate Change on Wetland
The main climatic drivers in the development of wetlands are precipitation and temperature, both of which are predicted to change significantly in response to climate change. There is unanimous agreement among climate models that atmospheric temperatures will increase, and that precipitation may increase or decrease, depending on location. As a result, the impacts of a changing climate on wetlands will be diverse and include:
- Small wetlands will dry up and disappear.
- Permanent wetlands will become seasonal and subject to greater variation in water levels.
- Biodiversity of plants and animals will decrease as habitat for wetland-dependent species and many plants and mosses, will be reduced or lost.
- The water retention and purifying ability of many wetlands will be impaired, resulting in increased flooding and lower water quality.
“The conservation, sustainable use and restoration of wetlands can contribute significantly to the achievement of the Paris ambitions as efficient and effective nature-based solutions for mitigation of climate change and adaptation to its impacts.”