Warming world “drying wetlands”

[Karl]

Tehran Times – July 24, 2008

Rising temperatures are not only accelerating evaporation rates, but also reducing rainfall levels and the volume of meltwater from glaciers. Although only covering 6% of the Earth's land surface, they store up to an estimated 20% of terrestrial carbon. Co-organized by the UN University and Brazil's Universidade Federal de Mato Grosso, the five-day Intecol International Wetlands Conference in Cuiaba, Brazil, will examine the links between wetlands and climate change.

"Humanity in many parts of the world needs a wake-up call to fully appreciate the vital environmental, social and economic services wetlands provide," said conference co-chairman Paulo Teixeira. These included absorbing and holding carbon, regulating water levels and supporting biodiversity, he added. Konrad Osterwalder, rector of the UN University, said that people in the past had viewed the habitats as a problem, which led to many being drained. "Yet wetlands are essential to the planet's health," he explained. "With hindsight, the problems in reality have turned out to be the draining of wetlands and other 'solutions' we humans devised."

Scientists warn that if the decline of the world's wetlands continued, it could result in vast amounts of carbon being released into the atmosphere and "compound the global warming problem significantly". Wetlands act as sponges and their role as sources, reservoirs and regulators of water is largely underappreciated. Max Planck Institute It is estimated that drained tropical swamp forests release 40 tons of carbon per hectare each year, while drained peat bogs emit between 2.5 to 10 tons. Data shows that about 60% of wetlands have been destroyed in the past century, primarily as a result of drainage for agriculture.

"Lessening the stress on wetlands caused by pollution and other human assaults will improve their resilience and represents an important climate change adaption strategy," explained Wolfgang Junk from the Max Planck Institute for Evolutionary Biology, Germany. "Wetlands act as sponges and their role as sources, reservoirs and regulators of water is largely underappreciated," Professor Junk added. "They also cleanse water of organic pollutants, prevent downstream flood inundations, protect river banks and seashores from erosion, recycle nutrients and capture sediment." The conference organizers said the ecosystems, many of which have biodiversity that rivals rainforests and coral reefs, were in need of complex long-term management plans. They hope the scientific meeting, which ends on Friday, will highlight the range of measures needed, such as agreements that covered the entire catchment areas of the wetlands.

Source: tehran times : Warming world 'drying wetlands'

[prowberr]

I am confused about the claim that greater evaporation is accompanied by lower rainfall. This seems counter-intuitive to me, especially as I am in the UK suffering a "heatwave" in July on the back of the wettest June on record.

There is a serious ecological issue related to desertification and the loss of wetlands, but much of this could be totally independent of climate change, IMHO. Most wetlands have been lost as a result of building in floodplains and draining marshes, not simply climate change. I do not argue with the premsie that wetlands may be an under-rated asset. However, in an imperfect world, they do get some of the highest levels of environmental protection available, with International treaties such as the RAMSAR convention offering a high level of protection.

[natureguy]

20-25% of food (fish, meat & rice) consumed globally is produced in Wetlands.