Half of the countries in the world have at least one type of freshwater ecosystem in a state of degradation, following impacts on lakes and mangroves, UN bodies said on Wednesday.
River flow has decreased, surface water bodies are shrinking, and water management is off-track, said UN-Water and UN Environment Programme (UNEP) in three reports on international progress on freshwater.
“The degradation of freshwater ecosystems, characterised by changes in the quantity and quality of water and/or loss of ecosystem area, directly impacts opportunities to develop sustainably and for nature to survive and thrive,” one of the reports said.
“The number of countries with degraded freshwater ecosystems is concerning because healthy and functioning freshwater ecosystems are essential for ensuring water and food security, mitigating climate impacts, and preserving biodiversity.”
The 50% figure follows the UN assessing countries against indicators – such as river flow, water quality, and mangrove area – for progress towards its Sustainable Development Goal for conserving water-related ecosystems over the five-year period up to 2021.
Some 90 of the assessed countries, mostly in Africa, Central and Southeast Asia, have degraded freshwater ecosystems, the UN said.
River flow has decreased in 402 basins worldwide, marking a fivefold increase since 2000, the papers said.
Human activities like aquaculture and agriculture have hit mangroves, posing a risk to coastal communities, freshwater, biodiversity, and the climate.
Lakes and surface waters are shrinking in 364 basins globally, with high nutrient levels causing algal blooms and low oxygen, driven by land clearance, urbanisation, and weather events.
However, reservoir construction has globally increased the amount of water that is present in one place throughout the year, mainly in the US, Europe, and Asia.
Degradation has been primarily driven by pollution, dams, land conversion, over-abstraction, and climate change, the paper said.
“For nature, freshwater ecosystem degradation can be catastrophic and, for example, has resulted in enormous decline in freshwater species populations globally – 83% since 1970 (WWF 2022).”
The poorest half of the world provides less than 3% of global water quality data, with only 4,500 lake measurements out of 250,000, highlighting the urgent need to boost monitoring capacity, the reports said.
“Lack of data on this scale means that by 2030, over half of humanity will live in countries that have inadequate water quality data to inform management decisions related to addressing drought, floods, impacts from wastewater effluents and agricultural runoff.”
The UN called for countries to use its “system-wide” water strategy, launched in July, while taking policy action.
By Thomas Cox – t.cox@carbon-pulse.com
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