2025 Ecological Threat Report (ETR).

The 2025 Ecological Threat Report (ETR) is a comprehensive, data-driven global assessment of ecological risks. It covers 3,125 sub-national areas in 172 countries and territories, representing more than 99 per cent of the world’s population. It measures four interlocking threats: water risk, food insecurity, the impact of natural events, and demographic pressure.

The main finding of this year’s report is the unexpected and sometimes divergent relationships between water and conflict. On the one hand, it finds that conflict death rates are 50 per cent higher in places where water stress is rising owing to heightened rainfall seasonality. On the other, it highlights how there have been no interstate wars fought over water in the modern era. In this regard, the hundreds of active freshwater treaties around the world demonstrate that strategic cooperation is effective when the downside risks are well-known, similar to nuclear non-proliferation treaties.

Precipitation patterns are shifting, and the seasonality of rainfall is increasing. Seasonality refers to the concentration of rainfall into fewer months within the year, resulting in wet seasons becoming wetter and dry seasons becoming drier, even though total annual rainfall may not change. This is occurring in over 60 per cent of the areas covered in the report, with the remainder recording a more even spread of rain throughout the year. In areas experiencing severe increases in rainfall seasonality, there are on average four times as many conflict deaths as in places where it is relatively stable or has notably decreased.

Analysis finds that rainfall seasonality tends to act as a risk multiplier rather than a core driver of conflict. These heightened risks are particularly acute where ecological fragility overlaps with rapid population growth and already-low rates of freshwater access. Sub-Saharan Africa is the most critically affected area, with per capita water usage having fallen from 113 cubic metres per person in 2000 to 89 as of 2022, less than one-fifth the global consumption rate.

When populations expand quickly, governance is weak, and there is a history of conflict and group grievances, rainfall shocks are more likely to generate competition over land, water, and food – and therefore violence. Modelling finds that when population growth exceeds roughly two to three per cent annually, heightened seasonality can add as many as six additional conflict deaths per year for every 100,000 people.

There are 263 international river basins globally with billions of people dependent on them for their freshwater. Their stability is paramount for both food security and international peace. Popular narratives have warned of looming “water wars”, especially in transboundary river and lake basins. The ETR’s review f inds a more positive reality: outright interstate wars fought exclusively over water have not occurred in the modern era. The importance of these systems is underscored by the 157 international freshwater treaties signed between countries in the second half of the 20th century, highlighting that countries understand the cataclysmic consequences of mass disruption to freshwater and food supplies.