Part 1

Setting the scene

Water, essential for life

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.

Fresh water: a precious resource

Composition of water on earth

A map showing that ...

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.

The scale of water-related disasters

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.

Large impacts of water-related disasters compared with other disasters and conflict

Average annual number of people affected and killed, and economic damage (in USD)

This graph shows the number of people affected, killed, and the economic damage for water-related disasters. These numbers are compared with numbers for earthquakes, epidemics, and conflict. It shows that the number of people annually affected and the annual damage are highest for floods, while the number of people killed annually is highest due to inadequate water and sanitation.

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.

The impact of water that is too dirty is highest in Africa and Asia

Annual deaths from diarrhoea (2012) and cholera (2008-2012) (in thousands)

A map showing that ...

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.

The impact of too little water especially affects the people in India,
China, and countries in the eastern part of Africa

People annually affected by drought 1996-2015

A map showing that ...

Source: CRED

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.

The impact of too much water is mainly concentrated in Southeast Asia

Number of people annually affected by flooding 1996–2015

A map showing that ...

Source: CRED

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 and weather extremes

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.

Shift in mean conditions, strong impact on extremes

This graph illustrates how a shift in mean temperature under global warming affects the probability of occurrence of cold and hot weather extremes. Compared with the past we will experience less cold weather events and more hot weather events in future decades. Also, record-high hot weather events will become more likely.

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.

Change in temperature 2010-2050

This world map shows the change in air temperature between 2010 and 2050. Global average temperature is projected to increase by around 2 °C by 2050. The northern regions face relatively high temperature increases.

Source: PBL

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.

Change in net precipitation, 2010-2050

This world map shows the change in average daily precipitation between 2010 and 2050. Most dry areas will become dryer and wet areas wetter.

Source: PBL

In general, the net result of changing temperature, precipitation patterns and evaporation is that most dry areas will become dryer and wet areas wetter.

Urbanisation changes global vulnerability

In the urbanising world, cities will increasingly become centres of population growth and economic development.

Cities with millions of inhabitants will continue to grow between now and 2050

Population in cities in 2010 and 2050

A map showing that ...

Source: PBL

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.

Strong links with Sustainable Development Goals

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.

Most of the Sustainable Development Goals are related to water

This graphs shows all the 17 Sustainable Development Goals. Almost all of these goals are related to water. Six of these goals have a very strong relation with water, such as good health and well-being, clean water and sanitation, and biodiversity.

Source: PBL

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.

Scenarios of increasing pressures

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.