Humans use water for everything from drinking and bathing to growing crops, supporting livestock and fish farms, shipping goods, generating electricity, and simply relaxing and having fun. Yet climate change is producing profound changes in this precious commodity, threatening water availability, access, and even quality.
See how global warming puts Lima, Peru's electricity supply at risk—and find other hot spots with water use impacts on the Climate Hot Map.
- Decline in drinking water—both quantity and quality—is expected for these reasons:
► Municipal sewer systems may overflow during extreme rainfall events, gushing untreated sewage into drinking water supplies.
► Loss of mountain snowpack and earlier spring snowmelt spurred by higher temperatures reduce the availability of drinking water downstream.
► The shrinking of mountain glaciers threatens drinking water supplies for millions of people.
► Sea-level rise can lead to saltwater intrusion into groundwater drinking supplies, especially in low-lying, gently sloping coastal areas.
- Decline in irrigation supplies. Loss of mountain snowpack reduces the amount of water available for irrigation downstream, while earlier spring snowmelt affects the timing. Saltwater intrusion may contaminate the supply from groundwater.
- Higher shipping costs. Lower lake and river levels may reduce the capacity of ships to carry freight safely due to the danger of their running aground or preclude the use of large ships altogether—both of which may increase shipping costs for food and other commodities.
- Disruptions to power supply. Lower lake and river levels may threaten the capacity of hydroelectric plants, while higher temperatures may mean that water is too warm to cool coal and nuclear power plants, leading to power brownouts. Shrinking mountain glaciers threaten electricity generation as well.
- Effects on recreation. Reduced snowpack and earlier spring snowmelt put traditional winter sports, such as skiing and snowmobiling, at risk, while lower water levels in lakes and rivers increase the costs of maintaining recreational amenities such as pleasure boat docks and even beaches.