Loss of wetlands smaller than assumed so far
The global loss of wetlands is smaller than hitherto assumed, according to the study Extensive global wetland loss over the last three centuries, published by an international research team headed by Stanford University/USA in February 2023. According to their research, since 1700, just 21 to 35 per cent of the world’s wetlands have been lost, rather than the 50 to 87 per cent presumed so far.
“This study bears out what we have always said about moors. In area terms, global loss is not as great as frequently claimed. But what appears to be good news at first glance must not deceive us. World-wide, around four million square kilometres of wetlands have been lost, including half a million square kilometres of wet moorland,” explains Hans Joosten, an expert on moors, co-author of the study and retired professor from the University of Greifswald/Germany. “However, the drained moors are responsible for four to five per cent of greenhouse gas emissions world-wide. They are relatively small areas, but have huge impacts! Wetlands, and moors in particular, continue to be threatened world-wide, with grave consequences for the climate, biodiversity and our livelihoods.”
For their study, which has now been published, the scientists scoured thousands of reports on draining and changes in land use in 154 countries in order to compare them with today’s distribution of drained and modified wetlands and thus gain an impression of the situation since 1700. This historical overview depicts how wetlands have turned into one of the most threatened ecosystems world-wide. The reasons have been draining for farming and peat digging as well as fires and groundwater extraction.
Today, moors are regarded as important water filters and stores, and also as carbon stores. They are seen as essential to livelihoods and health. The study enables a better quantification of changes in carbon storage by wetlands and in methane emissions. It also allows conclusions to be drawn on the impacts the loss of wetlands is having and how the planning of restoring wetlands can be improved.
(University of Greifswald/ile)