The Ramsar Convention on Wetlands (a global treaty ratified by 170 countries) recently published a report about the dramatic disappearance of wetlands, one of the most important ecosystems on Earth, and the most economically valuable according to environmental economists.
Wetlands, which comprise different types of ecosystems such as lakes, rivers, swamps, marshes, peatlands, mangroves and other coastal ecosystems, not only play a major role in the biosphere, but are also one of the most biodiverse biotopes on Earth.
Thirteen years ago, the Millenium Ecosystem Assessment warned that wetlands were extensively degraded compared to other natural ecosystems. Ramsar Convention’s recent report indicates that the situation continues to deteriorate: wetlands are disappearing three times faster than forests, according to the authors; a third of the world’s wetlands have been lost over the past 45 years (one half for Mediterranean natural wetlands), with annual rates of loss accelerating from 2000. There are many causes of deterioration. One of them is direct land-use change, specifically urbanization in coastal zones and river deltas led by population increase and development. Other factors include pollution, nutrient loading from fertilizers (leading to oxygen starvation), unsustainable use, invasive species, disrupted flows from dams, soil erosion and climate change. The graph below illustrates this deterioration for the world’s different regions.
Wetlands historical decline (from the Global Wetland Outlook 2018)
Wetlands cover more than 12 million km² globally. At some point, they are all inundated by water, either temporarily or permanently. These biotopes have a number of ecological functions, from water storage and purification to carbon storage, nutrient processing and disaster risk reduction. They provide almost all of the world’s consumed freshwater. They host an extensive number of species (about 40% of global biodiversity) that are often specific to these environments. Of over 19,500 wetland-dependent species assessed globally, one quarter are threatened with extinction. Wetlands also provide crucial ecosystem services to many local economies: about one billion people depend on wetlands for livelihood. Besides its visible consequences on the natural world, wetland deterioration constitutes as of now a major risk for global and local ecosystem stability, with direct economic implications.
The Global Wetland Outlook 2018 stresses the urgent necessity of developing effective wetland management plans and integrating wetlands into the planning and implementation of national plans on sustainable development, climate change and other key global commitments. Key steps stressed by the report include enhancing the network of Ramsar Sites (the Contracting Parties’ most significant wetlands) and strengthening legal and policy arrangements to conserve all wetlands. In many cases, these protective measures would directly come up against economic development planning, as deterioration most of the time directly ensues from it, for example infrastructure and agricultural development (about 70% of extracted water is dedicated to agriculture) and the construction of dams. On the latter, the report highlights damage that could be incurred by renewable energy policies and targets, which may call for dam multiplication around the world to replace non-renewable energy sources. As it can be seen, the issue is not only related to an “ancient” development approach and will remain still highly topical in a post-carbon perspective.
Hadrien Lantremange, Natural Capital Analyst - Sources: Millennium Ecosystem Assessment, Global Wetland Outlook 2018, Beyond Ratings