The ongoing destruction of world wetlands could cause them to exhale a massive amount of greenhouse gases, scientists have warned.
Meeting on July 21-25 in the city of Cuiaba on the edge of South America's vast Pantanal, the largest wetland of its kind, some 700 experts from 28 nations at the 8th INTECOL International Wetlands Conference will prescribe measures urgently needed to better understand and manage these vibrant ecosystems, ranked among the planet's most threatened, and slow their decline and loss.
Warming world temperatures are speeding both rates of decomposition of trapped organic material and evaporation, while threatening critical sources of wetlands recharge by melting glaciers and reducing precipitation.
Covering just 6% of Earth's land surface, wetlands (including marshes, peat bogs, swamps, river deltas, mangroves, tundra, lagoons and river floodplains) store 10-20% of its terrestrial carbon.
Wetlands slow the decay of organic material trapped and locked away over the ages in low oxygen conditions.
These waterlogged (either seasonally or year-round) areas contain an estimated 771 gigatonnes (771 billion tonnes) of greenhouse gases - both CO2 and more potent methane - an amount in CO2 equivalent comparable to the carbon content of today's atmosphere.
"Humanity in many parts of the world needs a wake-up call to fully appreciate the vital environmental, social and economic services wetlands provide - absorbing and holding carbon, moderating water levels, supporting biodiversity and countless others," said conference co-chair Paulo Teixeira, Co-ordinator of the Cuiaba-based Pantanal Regional Environmental Programme.
According to UN Under Secretary-General Konrad Osterwalder, "Too often in the past, people have unwittingly considered wetlands to be problems in need of a solution. Yet wetlands are essential to the planet's health - and with hindsight, the problems in reality have turned out to be the draining of wetlands and other 'solutions' we humans devised."
If the decline of wetlands continues through human and climate change-related causes, scientists fear the release of carbon from these traditional sinks could compound the global warming problem significantly.
Drained tropical swamp forests release an estimated 40 tonnes of carbon per hectare per year. Drained peat bogs release some 2.5 to 10 tonnes of carbon per hectare per year.
According to German expert Wolfgang Junk, the impact of climate change on wetlands is small so far compared to the damage caused by poor management at the local level.
"Lessening the stress on wetlands caused by pollution and other human assaults will improve their resiliency and represents an important climate change adaptation strategy," he said.