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Part 2 - Mapping hotspots

Ecological quality of aquatic ecosystems

Further biodiversity loss towards 2050

Overall, natural biodiversity will be preserved in less than 60% of the world’s fresh water ecosystems, under the Business-as-usual scenario.

Projected quality of fresh water ecosystems: further decline by 2050 except for northern regions

This world map shows the projected decline in the quality of fresh water ecosystems, between 2010 and 2050.
This decline is particularly strong in Sub-Saharan Africa and parts of Latin America and Asia. The map also shows that most of the original fresh water biodiversity will be gone by 2050, in large parts of the world, but not in sparsely populated northern regions.
This world map shows the projected decline in the quality of fresh water ecosystems, between 2010 and 2050.
This decline is particularly strong in Sub-Saharan Africa and parts of Latin America and Asia. The map also shows that most of the original fresh water biodiversity will be gone by 2050, in large parts of the world, but not in sparsely populated northern regions.

Source: PBL

High-quality ecosystems in tropical regions, including the most biodiverse river basins, are already severely affected. Quality decline will continue, especially in Sub-Saharan Africa and parts of Latin America and Asia.

Also in Europe, the United States and Japan/Oceania, most of the decline in quality has already occurred. In the sparsely populated northern regions, the quality of fresh water ecosystems will be least affected.

Fresh water ecosystems

The higher water temperatures due to global warming, in combination with higher nutrient emission levels, will affect the ecological quality of fresh water ecosystems.

Causes of fresh water biodiversity loss

Causal contribution to loss (in %)

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Source: PBL

The main drivers of biodiversity loss are population growth and unsustainable economic development; their impact will be reinforced by climate change. Cities with poor wastewater treatment will continue to grow, and the number of dams in rivers is projected to increase.

Marine ecosystems

The increase in nutrient emissions, towards 2050, will also result in an increase in nutrient loading to coastal waters, especially in the Asian region. This will increase the risk of toxic algal blooms and oxygen depletion in those waters, and will negatively affect biodiversity.

Quality of coastal seas threatened by increased nutrient loading

x billion kg N/year

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Source: PBL

Solutions

Preserving aquatic ecosystems requires an integrated ecosystem-based approach, on landscape scale, which acknowledges the diversity and quality of aquatic ecosystems.

Several solutions may contribute to preserving aquatic ecosystems

This illustration summarises five solutions to preserve aquatic ecosystems.
The five solutions to preserve aquatic ecosystems are: utilising ecosystems for flood protection, wetlands restoration, reuse of nutrients and improved wastewater treatment in cities, more efficient use of water and nutrients in agriculture, and the application of ecological criteria in hydropower.