The worldwide degradation of natural resources is one of the major societal challenges. Water is one of the most important resources for humankind. It is a prerequisite for life on our planet and cuts across many social, economic and environmental activities.
Composition of water on earth
Source: Shiklomanov, 1993
Only 2.5% of the water on earth is fresh water; about 70% of which is stored in ice, 30.8% in groundwater systems, and 0.3% is directly available in rivers and lakes.
Water security is related to three water-related challenges: water scarcity (too little water), water pollution (dirty water) and flood risk (too much water). In the coming decades, these challenges and their impact on people’s daily lives are expected to increase due to population growth, economic development, increased agricultural production and climate change, in turn affecting water availability, sea-level rise and weather patterns.
Average annual number of people affected and killed, and economic damage (in USD)
Source: CRED, Prüss-Ustün et al. 2014
Each year, water-related disasters, such as drought and flooding, affect approximately 160 million people. Flooding affects most of these people: 106 million, annually.
Fortunately, due to improved early warning systems and increased disaster management capacity, the number of people killed by weather-related disasters has decreased over the last decades. Far more people are killed by other types of natural disasters, such as earthquakes and tsunamis, as well as by violent conflict. Compared with these numbers, the annual number of people that die from inadequate water and sanitation is extremely high, however.
Flooding causes the largest economic damage: USD 31 billion, annually.
Annual deaths from diarrhoea (2012) and cholera (2008-2012) (in thousands)
Source: Prüss-Ustün et al., 2014, Ali et al., 2015
Because of unsafe drinking water and lack of adequate sanitation, each year, millions of children under the age of 5 become ill, and almost 800,000 people perish from diarrhoea and cholera. Africa has the highest annual deaths, but numbers are also high in Southeast Asia.
People annually affected by drought 1996-2015
Droughts lead to water scarcity for people, severe agricultural production loss, local food shortages, and wildfires. On average, 55 million people are affected by droughts, annually.
Number of people annually affected by flooding 1996–2015
Flooding occurs all over the world, but the majority of the people affected live in Southeast Asia. On average, 106 million people are affected by flooding, annually.
Climate change involves both slow and gradual changes, such as in temperature, precipitation patterns and sea-level rise, as well as changes in weather extremes, such as drought, flooding and storm surges.
Average weather conditions will shift.
Along with this shift, cold weather extremes will occur less frequently, and hot weather extremes more frequently.
Besides, hot weather extremes are becoming more extreme.
Global average temperature is projected to increase by around 2 °C by 2050, with large regional differences. The northern regions face relatively high temperature increases.
In general, the net result of changing temperature, precipitation patterns and evaporation is that most dry areas will become dryer and wet areas wetter.
In the urbanising world, cities will increasingly become centres of population growth and economic development.
Population in cities in 2010 and 2050
By 2050, 70% of the world population is projected to live in an urban environment, on 0.5% of the global land area. This urban area is expected to expand by more than 70%, not only in riparian and coastal areas and in deltas, but also in water-stressed regions, such as drylands.
In 2015, the world agreed on a complex set of global goals in the Paris Climate Agreement and the Sustainable Development Goals. Water is linked to these global commitments in many ways.
In the Paris Climate Agreement, adaptation to climate change is on the level of national commitments to mitigate or combat climate change itself by reducing greenhouse gases. Major climate adaptation challenges include water security issues with respect to increases in water scarcity, drought and flood risk, and increasing water temperatures affecting water quality and biodiversity.
Water is also linked to the Sustainable Development Goals. This link is particularly strong for a number of these Sustainable Development Goals,
less strong for most of the other Goals,
and indirect for a few of them.
What the future holds is uncertain, but projections can be made. To explore the future, the scientific community has developed scenarios that broadly outline characteristics of a possible global future, in terms of population growth, economic and technological development, global collaboration and urbanisation.
One of these scenarios is the so-called ‘Business-as-usual scenario’. Our narratives on future hotspots are generally based on this scenario towards 2050. This scenario combines moderate population and economic growth with high climate change that results in 3.7 °C temperature increase by 2100.