Water scarcity is a growing concern worldwide. With the global population continuing to rise and climate change affecting weather patterns, many wonder if we’re headed towards a future where water resources become critically low or depleted in some regions. Here are some key points to understand about the global water supply and whether we’re likely to run out.
How much freshwater exists on Earth?
Earth’s total water supply is estimated at around 1.386 billion cubic kilometers. However, only about 2.5% of that is freshwater that is usable by humans and ecosystems. The majority, around 68.9%, exists as ice caps and glaciers while 30.8% is groundwater. Only 0.3% of freshwater on Earth is found in rivers and lakes.
Are we using freshwater faster than it replenishes?
In some parts of the world, yes. The rate at which groundwater and water in lakes/rivers is used is faster than rainfall and snowmelt can replenish those sources in certain regions. For example, in India’s agricultural regions, groundwater extraction for irrigation exceeds natural recharge rates by an estimated 25%. However, from a global perspective, our usage rate is still within the replenishment rate.
How is water usage changing over time?
Global freshwater usage has increased dramatically in the past 100 years. Usage increased by over 600% between 1900 and 2000. The table below shows how different sectors contribute to global water usage:
| Sector | Water Usage (%) |
|---|---|
| Agriculture | 69 |
| Industry | 19 |
| Municipal | 12 |
The agricultural sector is by far the largest consumer of water resources globally. However, municipal and industrial usage are increasing over time while agricultural use is stabilizing.
What regions are most water-stressed?
Some of the most water-stressed countries and regions include:
- India
- China
- Australia
- The Middle East and North Africa
- South Africa
- Western United States
These regions have high water usage coupled with hot climates that lead to more evaporation and loss of stored water. Climate change is likely to exacerbate water stress in already vulnerable regions.
Will climate change impact global water supplies?
Yes. Climate change can negatively impact water supplies in a few key ways:
- Higher temperatures causing more evaporation of surface water.
- Changes to precipitation patterns and more frequent/severe droughts in some regions.
- Faster melting of glaciers that feed rivers and reservoirs.
- Rising sea levels causing saltwater intrusion into coastal freshwater supplies.
Climate change models predict increased rainfall overall globally, but distributions will be uneven with some wet areas getting wetter and already dry regions getting drier.
Can desalination and water recycling help?
Seawater desalination and water recycling/reuse are growing sources of freshwater supply. However, they come with challenges:
- Desalination is energy-intensive and expensive.
- Recycling water requires advanced treatment to ensure safety.
These technologies don’t make economic sense for all regions but will likely grow as water supplies become more constrained. Desalination produces over 90 million cubic meters per day globally as of 2019.
Will we run out of usable freshwater in the future?
It’s unlikely the entire planet will run out of freshwater anytime soon. However, certain regions will continue to experience extreme scarcity and shortages, especially due to climate change. Constructing pipelines and canals to import water from other areas may help some regions. Overall, more efficient use and allocation of water will be needed along with expanded sources like desalination and recycling. The global population will also need to stabilize at some point to put less pressure on limited supplies.
Conclusion
While Earth’s total freshwater supply is abundant, water scarcity issues arise due to uneven distribution and high usage rates in certain regions. Climate change will exacerbate shortages in already water-stressed and arid regions. Expanded use of technology like desalination and efficient irrigation methods can help. But truly addressing the problem will require stabilization of population growth and major improvements in how water resources are managed, especially in the agricultural sector.
