QCOSTARICA – Costa Rica is going through one of the worst droughts in history. Much less rain that normal has fallen in the Central Valley this year, in Liberia, Guancaste, it is going through the driest period since 1937.
Despite the rain of the last couple of days over the Central Valley, the national weather service – the Institutio Metereologico Nacional (IMN) – assures us that it will be short lived, back to little rain by the middle of September.
Maybe Costa Rica can take some lessons from the United Arab Emirates (UAE) which has one of the 10 driest climates in the world. It hopes the controversial technique of cloud seeding could help to increase its meagre annual rainfall, trying to squeeze every last drop of rain from its clouds by launching salt missiles into them from planes.
According to cloud seeders the process doesn’t actually create the weather it can only increase the chances of a producing raining and possibly increase the amount of rain that falls from the cloud. The way it’s done is by looking at local cloud formations and choosing the ones with the best chances of precipitation. They shoot missiles containing silver iodide and calcium chloride into the base of the forming cloud and depending on the amount of updraft present they select the amount of missiles to fire. If the updraft is mild only 1 or 2 salt missiles can be taken up by the cloud but if it’s a good updraft they will fire up to 6 missiles. Cloud seeding often makes it rain but it’s never guaranteed.
Desalination is the process of removing salt from sea water but it’s expensive and time consuming so cloud seeding is being considered as a less expensive and more productive option. Even with 33 desalination plants in the Arab Emirates only 42% of their water needs are being met. Cloud seeding creates anywhere from a 5-70% increase in falling rain compared to just letting Mother Nature do her thing.Cloud seeding produces in days what desalination would take years to produce according to the National Centre of Meteorology and Seismology (NCMS). The cloud seeding goal of the UAE is to select clouds directly over the aquifers in an effort to catch every single last drop.