The global importance of wetlands

THE GLOBAL IMPORTANCE OF WETLANDS

A
AA wetland is any stretch of land where water sits on the surface, or lies just beneath it, for all or part of the year. Ecologically these are intricate systems, home to plants and animals found nowhere else. Yet the Global Wetlands Alliance (GWA) reports that close to a third of the world’s wetlands have vanished since 1980, drained or built over for farmland, urban growth and the digging out of peat* and minerals. Many that remain have been degraded too – by run-off from farm chemicals, by factory waste, and by construction. * peat: a brown deposit formed by the partial decomposition of vegetation in wet acidic conditions, often cut out and dried for use as fuel
B
BPeople have always settled near wetlands, and these fertile places have shaped human history; for countless communities they hold deep religious, historical and archaeological meaning. ‘The daily livelihoods and welfare of millions rest directly on wetlands,’ notes Dr Anneli Voss, senior hydrologist and lead researcher at the Freshwater Systems Institute (FSI). ‘Across much of the developing world, huge numbers of families depend on farming the wetlands to get by.’
C
CWetlands matter environmentally as well. ‘For softening the effects of a changing climate, wetlands are among our most valuable tools,’ says Joran Mikkelsen, who heads Coastal Resilience at the Global Wetlands Alliance. He points to how they shield low-lying coasts from rising seas and from violent weather – the storms, hurricanes and floods that batter such areas. Coastal wooded wetlands supply food and fresh water and blunt the force of storms, and several agencies, the GWA included, are now working to bring back the coastal forest that has been lost. ‘You can achieve a great deal just by putting a few trees in the ground on each hectare – enough shade to shift a whole microclimate,’ he says. ‘Making climate projects real is less about money than people assume.’
D
DAwkwardly, the world’s wetlands also hold rich reserves of sought-after commodities – palm oil and pulpwood among them – and peatlands, whose soil is a waterlogged layer of part-rotted plant matter, are singled out above all. Drain a peatland for crops and it flips from a store of carbon into a source of emissions; on Lorenzo Brandt’s estimate, this single practice is behind close to a tenth of all the carbon humanity releases. Clearing the forest that grows on peat also makes destructive wildfires far more likely, and those pour enormous volumes of CO₂ into the air. ‘We are watching peat forests that shelter extraordinary wildlife disappear,’ says Brandt, head of Sustainable Land-use at the GWA, ‘sold off for a few decades of palm-oil earnings.’
E
EThe trouble begins the moment logging crews move in to fell the trees. They cut channels through the swamp so boats can get in and float the trunks back out along the same routes; these cuts then draw the water off the peatland, clearing the ground for corn, oil palms or pulpwood. With the water gone, bacteria and fungi attack the carbon locked in the peat, giving off carbon dioxide together with methane. The solid remainder, meanwhile, begins to sink – a slow settling known as subsidence – and since peat is around nine-tenths water, this ranks among the most worrying results of draining it. ‘In the tropics the surface drops by roughly three centimetres a year, so within fifty years vast areas of the Congo Basin and coastal New Guinea will sit below the water and flood,’ Brandt warns. ‘A disaster is being assembled; some regions stand to lose as much as a third of their land.’
F
FThese industries do their damage in ways easy enough to record, but Dr Cormac Halloran of the Global Nature Trust (GNT) argues that the quieter harms may prove far worse. ‘Silt washing off the land, and fertiliser with it, can be all but impossible to see,’ Halloran says. ‘Taking out more water than a system can spare is just as hard to notice. Now and then a dramatic headline appears – a river turning red, or catching light – but a wetland is rarely destroyed by one obvious blow.’ Even so, he blames no one for harming wetlands on purpose. ‘Two decades on this, and I’ve yet to meet a soul who set out to ruin a wetland,’ he says. ‘People almost never intend it; more often the harm is simply a side effect of earning a living.’
G
GBrandt, too, accepts that people need to make a living. ‘Restoring the variety of life in a wetland is exactly what we want – but we can’t ignore that local communities have to earn something from it too.’ The FSI takes the same view. ‘In a developing country, people will look after a wetland only if it holds real value for them and pays its way,’ says Voss. ‘For this to last, local residents must share in the planning and the decisions, and hold clear rights to use the wetland.’
H
HWetlands would fare better, Brandt suggests, if more governments recognised their long-term worth. ‘Attitudes differ from one government to the next,’ he says, noting that while some nations now make wetland restoration a priority, others still deny there is any problem. Voss, though, allows herself a guarded hopefulness. ‘More and more, people are grasping how much wetlands matter,’ she says. ‘The degradation is still racing ahead, true, but my sense is that things are slowly starting to turn.’

Question 1 - 4

Which paragraph contains the following information?

the claim that the harms which are hardest to see may do the greatest damage

a mention of wetlands defending coastlines against severe weather

an estimate of how much of the world’s carbon output comes from draining peatland

an account of the way tree-felling draws water out of peatland

the claim that the harms which are hardest to see may do the greatest damage

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