Wetland as Carbon Sinks

MA Salam, Gunajit Oinam, Abdul Malik, Hemanta Pokhrel,  LP Mudoi, Rajdeep Datta, SK Bhagabati
Wetland is an “areas of marsh, fen, peatland or water, whether natural or artificial, permanent or temporary, with water that is static or flowing, fresh, brackish or salt, including areas of marine water the depth of which at low tide does not exceed six metres”. Wetlands are amongst the most productive ecosystems on the Earth and provide many important services to human society. However, they are also ecologically sensitive and adaptive systems. It exhibits enormous diversity according to their genesis, geographical location, water regime and chemistry, dominant species, and soil and sediment characteristics. Globally, the area extent of wetland ecosystems ranges from 917 million hectares to more than 1275m ha with an estimated economic value of about US $ 15 trillion a year. They provide a potential sink for atmospheric carbon but if not managed properly, they become a source of greenhouse gases. However, only limited studies have been conducted to assess the roles and potentials of wetlands in carbon sequestration. They are often termed as “Nature’s Kidneys” of landscape because of their ability to store, assimilation and transform contamination lost from the land before they reach waterways.
Wetlands are also referred to as “Biological Supermarkets” because they have extensive food webs that attract animals species, they possess unique habit and they are also rich in biodiversity. Wetland soils contain a disproportionate share of the earth’s total carbon. Although they occupy only between 5% and 8% of the earth’s total land surface, their soils hold 35% or more of the estimated 1500 gigatons (Gt, or billion metric tonnes) of organic carbon that is stored in soils. Despite their importance, wetland have been historically underappreciated, and an estimated 87% of global wetland area has been lost since 1700. They ae threatened by pollution, transformation, water extraction, and modification. Such disturbance can undermine a wetland’s ability to capture carbon, but critically, damage to wetlands can also release significant amounts of carbon that have already been stored.
CARBON SINKS
Carbon sinks absorb more carbon then they release acting like sponges that can soak up carbon compounds such as carbon dioxide. They are either a natural or artificial (man-made) reservoir that can store carbon for an indefinite period. The process through which carbon sinks can remove carbon dioxide from the atmosphere is called “carbon sequestration”. Natural carbon sinks are plants, soil, and oceans. Drainage and degradation of wetlands can release significant amount of this stored carbon back into the atmosphere in the form of methane and reduce the ability of wetlands to sequester additional carbon. Better management practices can help protect these stored of carbon and the ability of wetlands to sequester it.  Plants grab carbon dioxide from the atmosphere to use in photosynthesis; some of this carbon is transferred to soil as plants die and decompose. Combined the Earth’s land and ocean sinks absorb about half of all carbon dioxide emission from human activities.
WHY ARE CARBON SINK IMPORTANT
Climate change is an immense challenge. The earth’s climate is changing at an unprecedented rate. The effects of a changing climate are many and vary by location, with intensifying storm activity, rising sea levels and more frequent floods and droughts predicted. Internationally renowned experts have highlighted that to void the most serious impacts of climate change we need to limit global warming to 2 degree Celsius between now and 2100.     (To be contd)