We neglect swamps and bogs at our own peril.

The ongoing loss of wetlands throughout the world is undermining water quality, worsening the impact of natural disasters, and reducing biological diversity according to researchers at the Worldwatch Institute.

Wetlands are areas that are saturated with water for part of the year--freshwater sites such as swamps, bogs, and marshes, and saltwater systems that include mangroves and coral reefs. Intact wetlands provide essential services, including the recharging of groundwater supplies on which drinking water depends. They also shield ecosystems from pollutants such as the nitrogen and phosphorus contamination that results from crop field drainage.

Wetlands are often drained or filled when dam construction projects alter the frequency of water flows; deltas and coastal ecosystems far downstream can also be harmed. Draining wetlands can cause water tables to fall and increase the likelihood of salinization of soils, water shortages, and flood-related disasters.

Water disruptions in South Africa led to extreme flooding in neighboring Mozambique in 2000. About half of South Africa's wetlands have been drained for agriculture; this loss of the wetlands' flood control capacity, along with high runoff resulting from overgrazed grasslands in South Africa's portion of the Limpopo River watershed, made the flooding in Mozambique especially severe. Wetlands loss in the U.S. Mississippi River basin also disrupted natural flood control, resulting in $19 billion in property damage during floods in 1993.

Analysts estimate that the earth lost about 50% of its wetlands in the twentieth century, due to a variety of factors: conversion of wetlands to agriculture, the spread of forest plantations, urban and rural development, pollution, and dam construction and other water projects. Because of the numerous essential services they provide, wetlands are estimated to be the most valuable ecosystem on earth: They contribute "$4.9 trillion of the $33.3 trillion estimated value of the biosphere each year," reports Worldwatch.

The prospects for restoring wetlands in the future are dim because their functions (and the services they offer) are complex and interconnected. Further degradation is a likely scenario, according to the Hadley Centre for Climate Prediction and Research, which estimates a minimum loss of 40% to 50% of coastal wetlands by 2080.

Source: Vital Signs 2001 by the Worldwatch Institute. W.W. Norton. 2001. 192 pages. Paperback. Available from the Futurist Bookstore for $13.95 ($12.95 for Society members), cat. no. B-2383.

Global Deaths by Disaster
Earthquake/Volcano  30%
Windstorm           15%
Flood               49%
Others               6%
Source: Munich Reinsurance Company
Floods account for nearly one-half of the human
deaths caused by natural disasters. Without the
protection afforded by functioning wetlands, the
impact of floods on societies throughout the world
would be even more severe.
Note: Table made from pie chart