A new scientific assessment by the Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES) links five major challenges facing the planet: biodiversity loss, water scarcity, food insecurity, public health risks, and climate change.
The Nexus Report reveals that these problems are interdependent. Handling them separately can lead to counterproductive outcomes. It also explains response options to tackle these issues in a more coordinated and cost-effective way.
The IPBES Nexus Report is the result of three years of work by 165 experts from 57 countries. It was approved by 147 member governments during the 11th session of the IPBES Plenary in Windhoek, Namibia.
More than 70 policy measures, referred to as “response options,” were assessed. The options are aimed at delivering co-benefits across what the report calls “nexus elements”—biodiversity, water, food, health, and climate change.
According to the report, the cost of ignoring these interlinked crises is enormous. Unaccounted-for economic costs are estimated at US$10–25 trillion per year. These costs come from biodiversity destruction, pollution, climate change, unsustainable food systems, and more.
Current strategies often focus on isolated issues. This fragmented approach leads to inconsistent governance. It also tends to concentrate on short-term financial gains at the expense of long-term ecological and social well-being.
“We have to move decisions and actions beyond single issue silos to better manage, govern, and improve the impact of actions in one nexus element on other elements,” said Professor Paula Harrison, a co-chair of the assessment.
Local observations of how an effort to boost agriculture in one region can sometimes lead to heavy fertilizer use, which pollutes water sources in a neighboring community.
Personal experience in a rural area informs my perspective. “ Several years ago, I volunteered at a community-based water monitoring program. We found that water bodies downstream from large farms had elevated nitrates” Paula said.
This affected local fish species, harming biodiversity. It also caused health issues when the water was not properly treated, especially among children.
The problem was not limited to water pollution. It extended to health costs, climate concerns, and food security—exactly what the Nexus Report stated
Biodiversity declines—between 2–6% per decade—were found across multiple indicators. This affects food supply, water quality, and the resilience needed to adapt to climate change. More than 50% of the global population now lives in areas facing severe impacts from biodiversity loss, water stress, and health burdens.
Consumption patterns and waste generation exacerbate these problems. Overconsumption in higher-income regions can drive pollution and resource depletion elsewhere.
Population growth in certain areas puts additional stress on water, food, and health systems. The report notes that 12 out of the 12 indirect drivers—such as GDP growth and overall food demand—have risen since 2001, intensifying direct drivers of biodiversity loss.
“Another key message from the report is that the increasingly negative effects of intertwined global crises have very unequal impacts, disproportionately affecting some more than others,” said Professor Harrison. This is especially true in low-income regions, small island developing states, and Indigenous communities.
Forty-one percent of people live in areas with severe biodiversity declines, nine percent face high health burdens, and five percent face chronic malnutrition.
These statistics show that people experience these crises differently. Small island communities, such as those in the Pacific, often endure intense storms and rising seas that threaten both water supplies and local crop systems.
When I visited a coastal community in the Philippines as part of a local non-governmental organization project, residents shared their struggles with saltwater intrusion affecting freshwater wells.
They also reported reduced fish stocks and declining tourism due to coral reef damage. This direct testimony is an example of how multiple challenges converge to create serious hardships, especially for communities with limited resources.
The Nexus Report stresses that inclusive decision-making processes can yield better outcomes. Engaging Indigenous Peoples, women, youth, and local stakeholders helps ensure diverse viewpoints.
It also improves accountability. When communities participate in co-managing natural areas, such as marine protected zones, research in the report shows fish stocks improve, water quality rises, and economic benefits like ecotourism increase.
The assessment examined 186 scenarios from 52 studies, extending to 2050 and 2100. It found that “business as usual” leads to “extremely poor” results for biodiversity, water, health, and the climate.
Problems can multiply if governments choose to prioritize a single goal—for example, expanding food production—without considering broader effects on ecosystems.
Professor Harrison explained: “The future scenarios with the widest nexus benefits are those with actions that focus on sustainable production and consumption…” This includes reducing pollution, conserving forests, restoring degraded lands, and curbing greenhouse gas emissions.
A personal encounter in a community near a restored wetland area explained these benefits. After a local government financed a mangrove replanting project, local families reported fewer flood events and greater fish catches.
They also developed small businesses around eco-tourism. It was a modest but noticeable case of how integrated approaches can work.
The report identifies more than 70 response options in 10 broad categories. Many are straightforward.
Restoring carbon-rich ecosystems, such as peatlands, soils, and mangroves, can reduce carbon emissions, preserve biodiversity, improve water quality, and stabilize local food sources.
These holistic solutions sometimes require upfront financing. However, the Nexus Report revealed that delaying action could double future costs.
For instance, failing to address biodiversity targets now could result in a surge of species extinctions and irreversible damage later.
For large-scale changes, the estimated annual financing gap for biodiversity alone can reach up to US$1 trillion.
Meeting the Sustainable Development Goals (SDGs) demands an additional US$4 trillion each year.
Yet, the cost of inaction is higher in the long term. Private financial flows damaging to biodiversity are around US$5.3 trillion annually, with US$1.7 trillion spent in subsidies that incentivize harmful practices.
Governments can reallocate these funds toward nature-friendly initiatives. For example, the city of Paris invested €47 million to help farmers switch to eco-friendly methods.
This reduced water pollution while preserving habitats. Another effective strategy is “One Health” integration, where health specialists, veterinarians, and environmental experts collaborate. Brazil’s Unified Health System illustrates this approach by designing joint responses to zoonotic diseases, malnutrition, and biodiversity threats.
Integrated governance is essential. Professor Pamela McElwee, another co-chair, said: “Our current governance structures and approaches are not responsive enough to meet the interconnected challenges…This can be addressed by moving towards ‘nexus governance approaches’: more integrated, inclusive, equitable, coordinated, and adaptive approaches.”
Such governance might include cross-sectoral committees that align agriculture, health, and environmental policies. It might also involve revising trade agreements to discourage resource exploitation.
Another solution is water-sensitive urban design, which uses wetlands or green spaces to manage floods, improve water quality, and provide recreational benefits.
From personal observation in my hometown, converting abandoned lots into small urban farms offered multiple benefits.
It improved local diets, reduced heat in the summer, and provided pollinator habitats. It also fostered community cohesion. These small examples shows the larger message: coordinated efforts can yield widespread improvements.
By the numbers – Key statistics from the report
- 2–6% biodiversity decline per decade across assessed indicators.
- >50% of the global population living in high-impact areas.
- US$10–25 trillion per year in unaccounted-for costs.
- US$5.3 trillion in private-sector flows damaging biodiversity.
- US$1.7 trillion in public subsidies with negative environmental effects.
- 21–37% of global greenhouse gas emissions attributable to the food system.
- 9 million premature deaths in 2019 linked to air and water pollution.
12,000–19,000 child deaths in Africa (2011–2020) contributed to by climate change.
