Geoengineering clouds: a hazy proposition? (Part 1)

With cloud seeding one of the few geoengineering techniques that is currently utilised, I thought it would be interesting to explore cloud geoengineering in greater depth. Approximately 52 countries are actively involved in cloud seeding (Figure 1).

Figure 1: Countries involved in weather modification programmes (Source: World Meteorological Organisation, 2014).  

In the rain-shadow state of Andhra Pradesh in India, 17% of total rainfall in 2008 was attributed to cloud seeding. In a monsoon-dependent country, agricultural livelihoods are closely intertwined with rainfall (Samaddar et al, 2013). Droughts resulting in crop failure have led to the suicide of over 300,000 farmers in the past 20 years in India (BBC News, 2015). 

The following video outlines the science behind weather modification.

It is interesting to note that countries involved in precipitation enhancement are also generally arid/water stressed regions. Key examples are North Africa, Central & South Asia, Middle East, Australia, China and Mexico (Figure 2). 

Figure 2: The number of months per year in which blue water scarcity exceeds 1.0 (Source: Mekonnen and Hoekstra, 2016)

Furthermore, water stressed regions are particularly located in areas of high population density. Approximately 4 billion people live under severe water scarcity for at least 1 month of the year. Populations who experience frequent water scarcity are significantly located in India (1 billion people), China (0.9 billion people), Bangladesh (130 million), US (130 million – primarily in Western and Southern states), Pakistan (120 million), Nigeria (110 million) and Mexico (90 million) (Mekonnen and Hoekstra, 2016). 

I think it's great that cloud seeding could potentially maintain water security in a warming world - however I feel sustainable water management is also required to achieve this. Integrating climate change, with both water demand & supply management, can help to increase resilience of water systems under changing conditions (Wang et al, 2014).

Stay tuned for Part 2 which will explore how clouds can be used in solar radiation management techniques.