Desalination and Sea Level Impact
Scale of Water Removal:
- Desalination involves extracting seawater and converting it into freshwater for human consumption, irrigation, or industrial use.
- Current global desalination capacity is approximately 95 million cubic meters per day, which removes around 35 billion cubic meters of seawater annually.
- Even a tenfold increase in desalination would remove around 350 billion cubic meters of water per year, equating to a reduction of approximately 1 millimeter in sea level rise annually.
Global Sea Volume:
- The Earth's oceans contain around 1.332 billion cubic kilometers of water.
- The contribution of desalination, even at a large scale, is minuscule compared to the total volume of the oceans.
Water Returning to the Ocean:
- Most desalinated water eventually returns to the ocean through evaporation, wastewater, and runoff. This limits the long-term reduction in sea levels.
Desalination as a Mitigation Tool
While desalination cannot significantly lower sea levels, it can help mitigate the effects of rising seas by addressing water scarcity and providing solutions for coastal resilience:
- Irrigation and Land Retention:
- Desalinated water used for irrigation and land restoration can retain water on land longer, slowing its return to the ocean.
- Infrastructure and Adaptation:
- Desalination provides freshwater for communities at risk of saltwater intrusion and rising sea levels, helping them adapt to climate change.
Conclusion
Desalination is not a solution for significantly lowering sea levels, but it can play a role in mitigating the impacts of sea level rise by providing freshwater for human use, agriculture, and industrial applications. It is most effective when combined with strategies to reduce greenhouse gas emissions, manage water resources, and build coastal resilience.