1. Most of the water used by humans is for agriculture
Agriculture consumes a significant amount of the world’s fresh water resources – it accounts for almost 70% of all water withdrawals. This number can rise to over 90% in countries such as Pakistan where agriculture is most prevalent. Unless significant efforts are made to reduce food waste and increase agricultural water productivity, water demand in the agricultural sector is projected to continue to increase in the coming years.
Growing food for livestock endangers the world’s ecosystems, which are at risk of degradation and pollution. Estuaries of rivers and lakes are experiencing blooms of environmentally unfavorable algae caused by the growing use of fertilizers. Accumulations of toxic algae kill fish and contaminate drinking water.
Large lakes and river deltas have shrunk markedly after decades of water withdrawals. Important wetland ecosystems are drying up. It is estimated that half of the world’s wetlands have already been affected, and the rate of loss has increased in recent decades.
2. Adaptation to climate change involves responding to changes in the distribution of water resources and their quality
Climate change affects the availability and quality of water resources. As global temperatures rise, extreme and irregular weather events such as floods and droughts have become more frequent. One reason is that a warmer atmosphere holds more moisture. The current rainfall pattern is expected to continue, resulting in dry regions becoming drier and wet regions wetter.
Water quality is also changing. Higher water temperatures in rivers and lakes reduce the amount of dissolved oxygen and make the habitat more dangerous for fish. Warm waters are also more suitable conditions for the growth of harmful algae, which are toxic to aquatic organisms and humans.
The artificial systems that collect, store, move and treat water have not been designed to accommodate these changes. Adapting to a changing climate means investing in more sustainable water infrastructure, from urban drainage systems to water storage.
3. Water is increasingly a source of conflict
From conflicts in the Middle East to protests in Africa and Asia, water plays an increasing role in civil unrest and armed conflict. More often than not, countries and regions compromise to resolve complex disputes in the field of water management. The Indus Waters Treaty, which divides tributaries of the Indus River between India and Pakistan, is one notable example that has been in place for nearly six decades.
But these old norms of cooperation are being increasingly tested by the unpredictable nature of climate change, population growth and subnational conflicts. Widespread fluctuations in seasonal water supplies – an issue often ignored until a crisis breaks out – threaten regional, local and global stability by affecting agricultural production, migration and human well-being.
4. Billions of people are deprived of safe and affordable water and sanitation services
, about 2,1 billion people do not have safe access to clean drinking water, and more than 4,5 billion people do not have sewer systems. Every year, millions of people fall ill and die from diarrhea and other waterborne diseases.
Many pollutants dissolve readily in water, and aquifers, rivers, and tap water can carry chemical and bacterial markers of their environment—lead from pipes, industrial solvents from manufacturing plants, mercury from unlicensed gold mines, viruses from animal waste, and also nitrates and pesticides from agricultural fields.
5. Groundwater is the world’s largest source of fresh water
The amount of water in aquifers, also called groundwater, is more than 25 times the amount of water in the rivers and lakes of the entire planet.
Approximately 2 billion people rely on groundwater as their main source of drinking water, and almost half of the water used to irrigate crops comes from underground.
Despite this, too little is known about the quality and quantity of available groundwater. This ignorance in many cases leads to overuse, and many aquifers in countries that produce large amounts of wheat and grain are being depleted. Indian officials, for example, say the country is facing an even worse water crisis, in large part due to a shrinking water table that has sunk hundreds of meters below ground level.