Since 1700, wetland areas worldwide have shrunk by 20%. This roughly corresponds to the area of all of India, according to a study by a group of scientists from the US, Canada, China, Switzerland and other countries.
Until now, it was not known how many wetlands have been destroyed on Earth over the past 300 years.
Estimates ranged from 28% to 87%. For the first time, researchers have combined global historical records with maps of today’s swamps.
The analysis showed that the scale of losses amounted to a fifth of the indicators at the beginning of the 18th century.
According to scientists, Ireland has lost more than 90% of wetlands, Germany, Lithuania and Hungary – more than 80%, Great Britain, the Netherlands and Italy – more than 75%. In total, 50% of wetlands have disappeared in Europe over the past three centuries.
For thousands of years, people have perceived swamps as places that need to be drained and turned into agricultural fields.
Combined with the climate crisis, groundwater extraction, fires and rising sea levels, this has made wetlands one of the most vulnerable ecosystems in the world, the study says.
Globally, more than 60% of losses were caused by drainage for upland crops, followed by conversion to rice fields (18%) and urbanization (8%), according to a scientific article.
Swamp destruction peaked in the 1950s when farmers were given government subsidies to drain land in North America, Europe and China.
Less than 1% was lost during peat extraction. Globally, peatlands store twice as much carbon as all forests, so these ecosystems are vital to conservation if the world is to meet climate goals, the scientists write.
Determining the exact figure is important because it can help conservation efforts.
The agreement on the Convention on Biological Diversity, signed at Cop15 in December 2022, states that 30% of land, sea and inland waters must be protected.
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