Cloud reflectivity enhancement - a technology that might just save our planet after all

From the start of this decade, scientists have started working seriously and investors have been putting handsome money towards alternative research techniques that will help the current Gloabal Warming scenario on Planet Earth. A number of techniques or solutions are being proposed. One of them, which basically attempts to increase the "albedo", or "reflectivity" of the clouds surrounding us, really caught my attention. The beauty of the concept lies in its simple yet effective nature. And if data has to be believed, its pretty cost effective too!


So what is this technique we are talking about here? To understand the theory, lets first try to understand a little bit of science involving the clouds. We all know that water from oceans and streams and rivers evaporate and rise up and finally form clouds. As the water content in these clouds reach a certain limit, they come down back to earth as rain. What not all of us know is that for the transition the vapour state to liquid state (the clouds are nothing but water droplets), water requires a non-gaseous surface. In the earths's atmosphere, this required surface is present in what the scientists refer to as Cloud Condensation Nuclei, or CCN. A typical cloud droplet is about 2 mm is diameter, whereas a typical CCN is about 0.02 mm in diameter.

Without the presence of CCN, the water vapor needs to be supercooled below 0 °C for cloud droplets to form. And on temperatures above 0 °C, the air needs to be supersaturated to above 400% humidty for the water droplets to form.

As you can understand, the higher the presence of CCN in the atmosphere, the more congenial it is for the formation of clouds. Usually, sea salt from the ocean, dust, soot and black carbon emitted from emitted from forest fire act as CCN. In regions where air pollution levels are high due to the presence of dust, soot or carbon particles in the air, the phenomenon results in dense haze. People in Delhi for example, experience that abundantly.

This concept of CCN are being used these days in a technique called Cloud Seeding, where scientists try to encourage rainfall by increasing the CCN concentration of the atmosphere, thereby encouraging cloud formation. The technique is also used these days by geo-engineers to increase the reflective capability of the clouds. Usually in the oceans,lower levels of dust and pollution results in a CCN concentration which is much lesser compared to land. The idea is to have small vessels spray sea water to the atmosphere . As the water evaporates, they form salt particles which acts as CCN.


It has been estimated that around 1.4 billion tonnes of sea water is required to be sprayed each year to raise our planets reflectivity to a level which will be able to compensate the current global warming.
Stephen Salter, professor of engineering design at the University Edinburgh, and Professor John Latham, from the National Centre for Atmospheric Research in Colorado are the minds behind the salt water spray strategy. According to Prof Salter, we need to raise the refelectivity level by atleast 10%. Small vessels like the one shown alongside are being proposed for the purpose of spraying salt water across the oceans of the World.


There are, however, much more tests and experiments needs to conducted for everyone to be convinced about the effectiveness of this geo-engineering technique. Not every one is convinced that this is a fool proof technique to combat or even reverse the effects of the high level of Carbon emissions on our planet. There are concerns that by artificially altering the clouds, we may create harmfull effects on our planet's delicate eco system. Lastly, it is not clear that the land areas of our planet will experience the cooling effect.

Whatever may be the concerns, most geo-engineers are sure that Cloud Reflectivity Enhancement will definitely slow down the severe global warming our Mother Earth is facing.