Freshwater biodiversity is degrading faster than terrestrial due to anthropogenic causes, according to the latest report by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES).
The Interlinkages Among Biodiversity, Water, Food and Health paper, also known as Nexus Assessment, was released December 17, 2024. It identified ‘nexus elements’: Biodiversity, water, food, health, and climate change, which are interlinked, influencing each other and producing consequences when combined.
Freshwater and marine coastal species are especially sensitive as they accumulate anthropogenic stressors such as pollutants and sediments across various ecosystems and watershed areas, the report said.
Water for food production accounts for about 80 per cent of human water needs and is regulated by ecosystems and geophysical processes that support biodiversity and provide ecosystem services essential for human well-being and health.
Wetlands and inland waterbodies, which comprise only 2.6 per cent of the land surface, play a crucial role in water regulation and mitigating climate change. However, they are the most affected and stand degraded due to anthropogenic activities and climate change, the assessment stated.
Forests, which capture, filter, and regulate water flow through vegetation and soil, provide freshwater to about 75 per cent of the world’s population (as of 2005). However, the decrease in forest area has negatively impacted water availability and quality, the paper highlighted.
“At least 50 diseases are attributable to poor water supply, water quality and sanitation,” the report noted.
Regarding marine ecosystems, the Nexus report stated that coral reefs face multiple threats, such as unsustainable fishing, climate change, ocean acidification and land-based pollution. It observed that about a third of reef-building coral species are endangered and may be wiped out globally in the next 10-50 years.
The disappearance of coral reefs directly affects about a billion people – roughly 13 per cent of the global population – who live within 100 km of coral reefs and benefit in terms of food, protection from extreme weather such as coastal storms and erosion, medicine, tourism, recreation, and livelihoods.
The assessment also observed that illegal resource extraction activities, including wildlife, timber, and fish trade, are valued at between $100-300 billion annually.
“In contrast, expenditure aimed at improving the status of biodiversity amounts to significantly less than 1 per cent of global gross domestic product (these positive flows are estimated at $200 billion per year),” it said.
Current policies and international agreements have seen limited success in controlling the impacts of economic pressures on these nexus elements, which collectively generate $58 trillion of economic activity, as per 2023 figures.
“For example, negative externalities across the fossil fuel, agriculture and fisheries sectors are currently estimated in the range of $10–25 trillion per year, reflecting the negative impacts of production and consumption in these sectors on biodiversity, climate change, water and health,” it said.
Despite these challenges, the report highlighted some successful examples of area-based conservation across the globe that align with the targets of the Kunming-Montreal Global Biodiversity Framework to effectively conserve 30 per cent of terrestrial, inland water, and coastal and marine areas by 2030.
These examples include the creation of public and private natural reserves, national parks, and other effective area-based conservation measures of special interest, the paper said.
“For example, marine protected areas in Chile and Australia have led to increases in biodiversity, greater abundance of fish for human consumption, and improved incomes for local communities and, in the case of Australia, increased tourism revenues,” it stated.
It also emphasised that indirect actions, such as improving the sustainable production and consumption of certain foods and increasing resource-use efficiency, supported ecosystem conservation and adaptation. Such actions helped to reduce pressure on land and water resources.
In some cases, commodity-wide and private industry commitments, such as Brazil’s Amazon Soy Moratorium, have reduced pressures on critical ecosystems through improved monitoring and more transparent efforts, the report noted.
Nexus-wide benefits emerged from integrating the conservation of marine and terrestrial biodiversity, which improved water quality in freshwater and coastal areas, said the assessment. It also strengthened natural infrastructure, such as riverside forests and mangroves, which serve as buffers against climate extremes.
Other measures, such as improving groundwater governance through cooperation and community water management, reduced the risks of floods and other hazards while enhancing food production and supporting climate change mitigation and adaptation.
Integrating disease management within landscapes, including inland waterbodies and seascapes, can reduce the risks of waterborne and other diseases while providing wider benefits from protecting water quality and biodiversity, the paper said.