Measuring the impact of ecological threats.

The map in Figure 1.1 highlights the severity of ecological threats faced by 3,125 subnational areas, with areas in red having an overall ETR score higher than 3.8 out of 5, indicating a very high level of threat. Of these subnational areas, 13.7 per cent face a very high overall level of ecological threat. These areas are home to an estimated 926 million people, or 13 per cent of the global population. By 2050, this figure is projected to rise to 1.4 billion people. There is considerable variation in levels of ecological threat both within and across regions. Europe and North America are the only two continents where no subnational areas face a high or very high level of ecological threat. Even in sub-Saharan Africa, the region with the highest overall average threat level, there are some subnational areas facing only a medium level of threat. While not all of the people in these areas will suffer from the direct impacts of adverse ecological conditions, the indirect impacts will be widely felt. This is especially true of the areas which are in countries facing conflict, civil unrest, or poor governance. In contrast, societies characterised by higher levels of per capita income, institutional resilience, and more abundant material resources are better equipped to withstand and adapt to shocks. The relationship between ecological degradation, conflict, and population pressures is highly systemic; when multiple stressors converge, they can amplify one another and drive instability. But countries with stronger institutions and more equitable resource distribution are better able to buffer these impacts. In such contexts, ecological threats may still generate hardship, but they are less likely to escalate into conflict or systemic breakdown, as resilience mechanisms help limit primary impacts and speed recovery. Countries with high levels of societal resilience can withstand higher systemic shocks, such as floods, droughts or pandemics, and in the aftermath, they can become more resilient to future shocks. However, once a shock overpowers a societal system, then it degrades the system, making it less resilient to future shocks. This is especially evident when multiple shocks occur simultaneously or in quick succession, such as conflict, governance failures, and drought. As further illustrated in Figure 1.2, the most vulnerable countries are clustered in certain geographical regions: sub-Saharan Africa, South Asia, and the Middle East and North Africa. These regions are also the least peaceful, as measured by the Global Peace Index (GPI). 

Sub-Saharan Africa has the worst average ETR score, with 25 of the 45 countries in the region facing very high levels of ecological threat. The region has the highest average scores across all four ETR indicators. As shown in Table 1.1, nine of the ten countries with the highest ETR scores are in sub-Saharan Africa. Moreover, the number of people living in highly threatened countries is projected to rise significantly over the next several decades. While no country in sub-Saharan Africa records better than a medium level of overall ecological threat, there are a few that perform well in certain indicators. Despite recent upticks in food insecurity, Botswana recorded the region’s best ETR score in 2024, supported by its low demographic pressure and impact of natural events scores. Elsewhere in the developing world, there are certain countries with ETR scores near the top of the rankings. In Latin America, for example, Costa Rica, Uruguay, Chile, and Argentina all registered low levels of ecological threat last year.

By 2050, sub-Saharan Africa's population is predicted to rise to more than two billion, an increase of nearly 70 per cent, placing greater pressure on existing food and water supplies. Most countries across sub-Saharan Africa are dependent on rain-fed agriculture, making the region particularly vulnerable to changes in climatic conditions, such as prolonged droughts and seasonal floods.3 Agriculture is the mainstay of most economies in the region, accounting for just over 17 per cent of value-added GDP, higher than in any other region South Asia has the second worst overall ETR score. The region has the second highest scores in three out of the four ETR indicators: water risk, food insecurity, and the impact of natural events. Natural disasters – such as floods, hurricanes, and other sudden shocks – are comparatively common in the region and can exacerbate other ecological threats, particularly resource scarcity.

This edition of the ETR is the first to include time series data. Covering 2019 and 2024, it demonstrates medium-term changes in levels of ecological threat around the world. The steepest increases in ecological threat since 2019 cluster across a belt running from northwestern Africa to coastal West Africa. The deteriorations in North Africa are closely tied to surging water risk. Tunisia, Algeria, and Morocco all moved sharply upward due to a mix of prolonged drought, extreme heat, and increasingly erratic rainfall, which weakened communities’ ability to store and access freshwater. However, the scale of the deteriorations in these three countries can in part be attributed to unusually favourable rainfall conditions in 2019, which set a baseline against which later deteriorations appeared more severe. Effective water capture and storage remain a persistent challenge globally. For example, data from the Food and Agriculture Organization (FAO) shows that the average amount of countrylevel dam capacity has risen by more than 15 per cent since 1990. However, these gains have not kept pace with population growth, and average dam capacity per person has fallen by around 35 per cent in the same period. Moreover, around the world, most people do not get their water from dams, and groundwater supplies at least part of the drinking water for up to half of the world’s population and makes up about 43 per cent of global irrigation use. In the world’s poorest regions, population growth and climatic changes are expected to intensify water insecurity. Investment in small-scale water capture projects, such as sand dams, could be transformative: for example, large sand dams can hold more than 70,000 cubic metres of water, enough to fully irrigate between six and nine hectares of land.5 Of the thousands of sand dams in the world, most are in sub-Saharan Africa, especially East Africa, though examples also exist in southern Africa, South Asia, and parts of Latin America. However, precise global figures are lacking, as sand dams are typically built at the community level and are often poorly recorded. Filling the many knowledge gaps about the prevalence, performance, and hydrological impacts of various forms of water capture will be critical to evaluating their potential as a scalable adaptation strategy. Tunisia recorded the largest increase in ecological threat levels of any country in the ETR, driven by marked increases in water risk and exposure to natural events. Of the 20 subnational areas that deteriorated the most between 2019 and 2024, nine were in Tunisia. Leading these was the city of Manouba, part of the Tunis metropolitan area. Deteriorations of this kind contributed to the Middle East and North Africa recording the greatest overall increase in ecological risk of any region between 2019 and 2024, as shown in Figure 1.4. In contrast, Western and Central Europe showed by far the largest improvement, and this was also driven by water issues. However, in the inverse of the case of northwestern Africa, this reflected a reversion to long-term norms. Europe experienced anomalous dryness across much of the continent in the late 2010s, which set uncharacteristically poor baseline scores.

Figure 1.5 tracks the indexed global trend and shows that the overall level of ecological threat has risen by 0.8 per cent since 2019, a significant shift given the slow-moving nature of environmental systems. This was driven by a 2.9 per cent increase in the impact of natural events indicator, particularly in the form of floods, storms, and heatwaves – with 2024 declared the hottest year on record by the World Meteorological Organization. Demographic pressure is the only ETR indicator not shown in the figure, as this indicator is forward-looking and does not include time-series data. The indexed trends demonstrate the relatively high volatility of specific indicators. Water risk and the impact of natural events, which are tied to highly variable weather systems and climatic conditions, swing from improvements to deteriorations from year to year. In contrast, food insecurity, shows a more consistent trendline. In the context of the first years of the COVID-19 pandemic, food insecurity spiked as food systems, markets, and supply chains were disrupted. But in the past few years, food insecurity has gradually reduced, though it still remains worse than its pre-pandemic levels.