Cambridge IELTS 19 Academic Reading Test 3 (Questions 18-22) (Online Test)

The global importance of wetlands

D

The world’s wetlands are, unfortunately, rich sources for in-demand commodities, such as palm oil and pulpwood. Peatlands – wetlands with a waterlogged organic soil layer – are particularly targeted. When peatlands are drained for cultivation, they become net carbon emitters instead of active carbon stores, and, according to Marcel Silvius, head of Climate-smart Land-use at WI, this practice causes six per cent of all global carbon emissions. The clearance of peatlands for planting also increases the risk of forest fires, which release huge amounts of CO₂. ‘We’re seeing huge peatland forests with extremely high biodiversity value being lost for a few decades of oil palm revenues,’ says Silvius.

E

The damage starts when logging companies arrive to clear the trees. They dig ditches to enter the peat swamps by boat and then float the logs out the same way. These are then used to drain water out of the peatlands to allow for the planting of corn, oil palms or pulpwood trees. Once the water has drained away, bacteria and fungi then break down the carbon in the peat and turn it into CO₂ and methane. Meanwhile, the remainder of the solid matter in the peat starts to move downwards, in a process known as subsidence. Peat comprises 90 per cent water, so this is one of the most alarming consequences of peatland clearances. ‘In the tropics, peat subsides at about four centimetres a year, so within half a century, very large landscapes on Sumatra and Borneo will become flooded as the peat drops below water level,’ says Silvius. ‘It’s a huge catastrophe that’s in preparation. Some provinces will lose 40 per cent of their landmass.’