Recent Loss of Freshwater Wetlands Worldwide Valued at $2.7 Trillion per Year
By Sandra Postel of National Geographic’s Freshwater Initiative in Water Currents on June 24, 2014
Nova Scotia’s wetlands provide billions of dollars worth of benefits in ecosystem services to Nova Scotians annually. Thus the economic consequences of wetland loss can be substantial. Estimates are that wetland loss to development in Nova Scotia equates to about $2 billion annually in lost ecological services like water purification, recharging drinking waters and enhancing fishery productivity. Photo source Gov. of Nova Scotia.
[dropcap]T[/dropcap]he question of whether to drain a wetland to make way for a shopping mall or a cornfield, or to instead leave the wetland intact, often seems like a no-brainer: the “development” options have a clear dollar value, but the wetlands themselves do not.
But therein lies a big problem.
Wetlands do vital work. They recharge groundwater, keep rivers and lakes clean by filtering out pollutants, and provide habitat for birds and wildlife. About half of North America’s bird species depend in some way on wetlands.
Wetlands also mitigate the impacts of droughts and floods, a function increasingly important as the world experiences more weather extremes under a changing climate. They act like a sponge, absorbing and holding heavy rains, and then release that water more gradually to surrounding streams and aquifers. In this way they can lessen damage from both floods and droughts.
In the Mississippi River Basin, for example, the loss over many decades of 35 million acres of wetlands (an area the size of Illinois) in the upper watershed likely contributed to the impacts of the epic flooding in 2011, as well as of the extreme low flows during the drought the following year, when ship navigation between St. Louis and Cairo was at risk of shutting down.
The problem is that most of the time no one pays for the services wetlands provide. Lacking tangible, market or “dollar” value, they are drained, filled and lost to other uses.
According to a new study in the journal Global Environmental Change, the global area of freshwater wetlands and floodplains shrank by nearly two-thirds between 1997 and 2011, from an estimated 165 million hectares (408 million acres) to 60 million hectares (148 million acres).
