4 December 2015: The UN Environment Programme – World Conservation Monitoring Centre (UNEP-WCMC) has created an indicator for measuring change in wetlands. Called the Wetland Extent Trends (WET) index, the tool shows that the global extent of natural wetlands declined by 30% between 1970 and 2008.

The index also shows that marine and coastal wetlands are declining more quickly than inland wetlands and that regional differences can be identified, with figures varying from about 50% in Europe to about 17% in Oceania.

The WET index compiles time-series records from around the world to assess changes in the extent of natural wetlands at a global and sub-global scale. It is based on the Living Planet Index, which is used to measure global trends in wild vertebrate species abundance. Drawing on over 1,000 different time-series records, the WET index makes use of both ground-based and remotely sensed data and can be updated as more records become available.

Matthew Dixon, creator of the WET database, noted that the WET index is useful for evaluating progress on wetland-related policy objectives including those adopted under the Ramsar Convention and the Convention on Biological Diversity (CBD). Matt Walpole, leader of the study, explained that given wetlands’ importance for water security, food security and human health, the WET index could have an important role as an indicator for the Sustainable Development Goals (SDGs).

The WET index is published online in the journal Biological Conservation. [UNEP-WCMC Press Release]