Background As global demand for food and water grows, there is increasing pressure on the world’s freshwater supplies. Climate change is responsible for some surface water loss, as weather patterns become hotter and dryer in some regions, prolonging droughts and accelerating evaporation. Although climate change has significantly affected water supplies, to place exclusive blame for global water shortages on that factor alone, risks ignoring other anthropogenic sources of water crises. World freshwater supplies are abundant and technically enough to sustain society, but they are not uniformly distributed. Supplies are often lacking in areas where they are most needed. The problem is made worse as those same areas intensively use the few water resources that exist, diminishing available water supplies. The problem is unlikely to abate any time soon, as populations continue to grow bringing a need for increased food and energy supplies. The ability to meet those demands, while maintaining economic growth, continues to be tied to freshwater consumption. Comment As consumption of freshwater has increased, the effects have become increasingly visible. Worldwide, up to four billion people endure water scarcity for at least one month each year. Water crises have been ranked among the top global systemic risks. As the situation has continued to develop, freshwater sources in dry areas have started to run out, including a significant number of major rivers. The Colorado River, which runs through the United States and Mexico, has been dammed, diverted and used to supply 30 million people with drinking water. In addition to this, 70 per cent of the river is used to irrigate cropland. So much pressure on one source of water has caused the river to drop to alarmingly low levels and now it no longer reliably reaches the sea. The climate in the region is predicted to become increasingly warm, which is likely to lead to further reductions of between 5 and 40 per cent in flows over the next 40 years. A similar situation is playing out in rivers and lakes around the world, particularly in places such as India, the Middle East and Australia. These areas were identified by a study as water risk ‘hotspots’, where overuse of freshwater has created shortages. India, for instance, has four per cent of global freshwater, but has the second-highest levels of farm output, in part due to to a wide-ranging irrigation network. Eighty per cent of India’s fresh water is used for irrigation. India’s population is projected to reach 1.6 billion by 2050, but climate change is expected to negatively impact its agricultural yields. By investing in better water management and irrigation policies now, India may be able to avoid further water insecurity. A lack of access to water is not only a problem in its own right, but also has significant negative impacts on food security and the economy. According to a report by the World Bank, water shortages in certain regions could reduce GDP by up to six per cent. If those losses occur, they will be particularly damaging in developing countries such as Ethiopia, where rapid economic growth has been facilitated, in part, due to heavy water use and poor water management. Even advanced economies face economic risks as water resources become scarce. Low water levels in the Rhine, which flows through the industrial heartland of Germany, last year contributed to billions of dollars of lost revenue among farmers and factories. Climate change is very likely to continue to exacerbate water shortages, especially in already dry regions. In the absence of comprehensive and sincere international efforts to mitigate climate change, however, local, national and regional initiatives will become more important than ever in reducing water consumption and mismanagement. By doing so, it will be possible to reduce the frequency and effects of future water crises.