Explained | Why wetlands are so important for environmental sustainability, climate resilience, and human wellbeing

By Dr. Partha Jyoti Das

’Crucially, it is time to acknowledge wetlands’ critical role for biodiversity – and the solutions they provide on climate change and sustainable development. It is time to fulfill commitments to stop the loss of the world’s wetlands” – Martha Rojas Urrego, Secretary General of the Ramsar Convention on Wetlands

What is a wetland?

Scientists have defined wetlands in various ways and words. Considering all quintessential features, wetlands can be described as land areas submerged by or saturated with water which must have a land-water interface and a distinct ecosystem of themselves. They can be natural or human-made, inland or coastal, permanent or temporary, static or flowing, vegetated or non-vegetated.

Globally, wetlands can be categorized into three classes: Inland wetlands (swamps, marshes, lakes, rivers, underground aquifers, floodplains, peatlands, and wet grasslands); Coastal wetlands (saltwater marshes, estuaries, deltas and tidal flats, mangroves, lagoons, and coral reefs) and human-made wetlands (household ponds, tanks, fish/farm ponds, rice or paddy fields, and salt pan).  In the Indian context, the variety of water bodies that are seen everywhere including plains, hills, and mountains, and are called a variety of names like the marsh, swamp, pit, pond, tank, etc. are considered wetlands.

Wetlands are formed because of the interaction of natural hydrological, geomorphological, and geological factors and processes. They are vital components of the earth’s surface environment as well as the biosphere because they support exceptionally high biological diversity which places them among the most valuable ecosystems on the planet.  Wetlands play a crucial role in the hydrological cycle and facilitate the exchange of water and sediment with associated rivers and floodplains through hydrological connectivity.

Why are wetlands important for human beings?

Wetlands contribute to human well-being in many ways.  For example, wetlands provide a wide range of ecosystem services that are vital for the existence of a large variety of flora, fauna and also for the survival and subsistence of human beings.  About 40 percent of all plant and animal species live or breed in wetlands. Wetlands contain more biodiversity than forests, holding 40% of the planet’s species on just 7% of the land. Over 140,000 species of the world including 55% of all fishes – rely on wetlands and associated freshwater habitats for their survival. About 12 percent of the globally threatened bird species depend on wetlands as habitats.

Wetlands provide food, fiber, and raw materials for many different human uses, support the rich biological diversity of aquatic plants and organisms, and add recreational and educational value to the landscapes they belong to. Wetlands deliver food to poor and marginalized communities for consumption and resources for eking out various livelihoods, especially in rural areas.

Wetlands moderate extreme climate events like flooding and drought, facilitate clean water supply, help in groundwater recharging, and control the micro-climate of their surrounding areas. Wetlands also act as carbon sinks and climate stabilizers on a global scale thus helping in the mitigation of global warming and climate change. Wetlands play an important role in the nature-based solution, especially for climate change mitigation and adaptation.

Wetlands cover seven percent of the earth’s total surface area, and they yield 45 percent of the total natural productivity and ecological services of all natural ecosystems on the planet. Globally, the aerial extent of wetland ecosystems ranges from 1.5 to 1.6 billion hectares with an estimated economic value of the benefits accrued to humankind of about US$20 trillion a year.

What is the status of wetlands in India?

The landmass of India possesses, supports, and sustains diverse and unique wetland Habitats. The high mean annual rainfall of over 1150 mm, varied topography, and suitable climatic regimes, that the country is endowed with make it a rich repository of myriads of wetlands.  The natural wetlands found in the country usually range from the high-altitude Himalayan lakes, floodplain wetlands of the major river systems, saline and temporary wetlands of the arid and semi-arid regions, coastal wetlands such as lagoons, backwaters, estuaries, mangrove swamps coral, reefs, to the marine wetlands.

According to the most recent estimation done in 2017-18 by the Space Application Center, Ahmedabad, Government of India, India has a total wetland area of about 15.98 million hectares (mha) which is approximately 4.86% of the total geographic area of the country. A total of 2,31,195 wetlands (with an area larger than 2.25 ha) were mapped in this study. The major wetland types in terms of area coverage are river & stream, reservoir, intertidal mudflat, and tank/pond.  More than one-third (35.2%) of the total wetland area is covered by rivers and around 43% wetland area is covered combinedly by reservoirs (17.1%), intertidal mudflat (14.4%), and tank/ponds (11.4%). Out of the human-made wetlands, number of reservoirs in the country are 12,802 (5.5% of the total number of wetlands) covering 11.81 mha area, whereas tank/ponds are 1,51,815(65.7% of the total wetland numbers) covering 1.81 mha area. India has 75 ‘wetlands of international importance’ (also called Ramsar sites as explained later in this article). 

According to the study, there has been an increase in the number of wetlands by 18810 as well as in the area of wetlands by 0.64 mha compared to the figures obtained during the survey done in the year 2006-07. However, most of this increase is observed in the case of inland human-made and coastal human-made wetlands. Various other sources and media reports have, however, indicated a sorry state of affairs so far as natural wetlands are concerned.

What are the threats to wetlands?

Wetlands are the most threatened and maximally damaged natural ecosystem on the earth. All over the world wetlands are facing widespread degradation due to encroachment, landfilling and conversion to other land use (such as agriculture, settlement, and business areas), rapid urbanization, pollution (e.g., solid waste, industrial effluent), hydrological(flow) alterations including flow fragmentation, overexploitation of aquatic resources (e.g., overfishing), excessive siltation on the bed and banks and consequent reduction in water carrying capacity, eutrophication, invasive species, degradation and loss of connectivity to nearby channels, geomorphological changes and structural intervention on upstream rivers and climate change, etc.

Globally, wetlands are vanishing three times faster than forests and their rate of disappearance is increasing. About 90% of wetlands have been degraded or lost since the 1700s and 35% have disappeared since the 1970s, at a rate that is the fastest rate in comparison to other major ecosystems.

In India, many ecologically, socio-economically, and culturally important wetlands, especially smaller ones, have disappeared or degraded of late succumbing to pressures of growth in the settlement, agriculture, urbanization, and other development activities. However, there is no proper enumeration of such frequent loss of wetlands or of the degraded status of wetlands.

Climate change and wetlands

Climate change affects wetlands in various ways, while wetlands provide means for mitigation and adaptation to climate change. Rising atmospheric temperatures, extreme heat, fires, and droughts, afflict harm to the wetland ecosystems and cause their degradation. Degradation and loss of wetlands can amplify global warming and climate change by releasing large amounts of greenhouse gases. A degraded wetland can emit more methane than a healthy wetland.

The fact that wetlands are the most effective carbon sink in nature enables them to play an important role in reducing the volume of carbon dioxide in the atmosphere and thereby help in limiting global warming. For example, peatlands that cover just three percent of the planet, store nearly a third of all land-based carbon, which is twice as much as all the world’s forests. Coastal wetlands such as salt marshes, mangroves, and seagrass beds also have carbon-sequestering properties. This is how wetlands help in the mitigation of climate change.

Coral reefs and mangroves can moderate the impact of storm surges and tsunamis in coastal areas. Similarly, inland wetlands can soak up rain, reduce flooding, pacify wildfires, and delay the onset of droughts. Thus, wetlands can help in disaster risk reduction, climatic adaptation, and resilience building of nearby communities. Therefore, the protection, restoration, and sustainable management of wetlands is an efficient means of climate change mitigation and adaptation, for which wetlands are considered to provide some of the best nature-based solutions to climate change.

Why should we conserve wetlands?

Once we come to realize the real values of the wetlands as mentioned above and understand the importance of the ecological goods and services provided by them for human survival and sustenance, it hardly needs any explanation as to why we should strive our best to conserve our wetland and associated aquatic ecosystems and use their resource sustainably. Recent scientific investigation has revealed many more subtle aspects of the myriads of functions performed that were hitherto unknown to us, through which wetlands are providing us a natural environment for biodiversity to thrive and for human societies to flourish.

Protecting, restoring and wise use of wetlands can help us directly in the achievement of 10 out of the 17 Sustainable Development Goals, that the UN has envisaged being achieved in all countries to ensure poverty eradication, inclusive human welfare, and sustainable development. These are SDG 1(No poverty), 2(Zero hunger), 5(Gender equality), 6(Clean water and sanitation), 8(Decent work and economic growth), 9(Industry, innovation, and infrastructure), 11(Sustainable cities and communities), 13(Climate action), 14(Life below water), 15(Life on land).

International and National Initiatives

World Wetlands Day (WWD) is celebrated every year on 2nd February to commemorate the anniversary of the Convention on Wetlands, which was an international treaty signed by some countries of the world on February 2, 1971, in Ramsar, Iran. This convention (More well known as the Ramsar Convention) is an intergovernmental mechanism that provides the framework for the conservation and wise use of wetlands and their resources through national action and international cooperation. The convention at present has 172 member countries. It has designated 2471 Wetlands of International Importance (also known as Ramsar Wetlands or Ramsar Sites) all over the world with a total surface area of about 256 mha) covered by them. Wetlands can be designated as Ramsar Sites if they fulfill one or more of the nine specific criteria suggested by the convention which are related to mainly the ecohydrological character and biodiversity richness of the wetland.

The main objective of the WWD is to raise awareness about the value of wetlands, and the need to reverse their rapid loss and encourage actions to conserve and restore them.  The theme for the WWD treaty signed about 50 years back this year (2023), ‘It’s ‘Time for Wetland Restoration’ has been conceived in tune with the urgent need to rejuvenate the degraded wetlands all over the world as well as conforming to the UN Decade on Ecosystem Restoration being observed over the present decade (2021-2030).

India has many laws and policies that address various management needs of wetlands and their ecosystems. Examples are Wildlife (Protection) Act, 1972; the Water (Prevention and Control of Pollution) Act, 1974(Amended in 1978 and 1988), the Forest (Conservation) Act, 1980; the Environmental (Protection) Act, 1986; the National Environment Policy, 2006; National Water Policy, 2012; National Plan for Conservation of Aquatic Ecosystems (NPCA), 2013; and Wetland (Conservation & Management) Rules, 2017(under EPA, 1986).

Preserving water bodies and associated wet ecosystems has remained a common practice throughout history among communities in India.  However, in recent times we have lost sense of this synergy between nature and human societies. We need to strengthen this connection and initiate sincere endeavors to protect, conserve, restore, and wisely use wetland resources through proper implementation of our national policies and programs. 

(Dr Partha Jyoti Das is the inhouse Expert of Climate Fact Checks and Head of ‘Water, Climate and Hazard Division’, Aaranyak)