Shading the Planet
If we could just shut off the Sun for half an hour a day the problem of climate warming would be solved (actually, it would take less than that) but of course it is not easy. However, as it is noted in the FTI’s report, in the coming years several techniques that have been developed in the past are likely to reach a point of fruition. They aim at shutting off the sunlight by placing something in between the Sun and the planet surface.
We are actually experiencing this (partial) blocking of sunlight when the sky is overcast, clouded. So the researchers have been looking for ways to create clouds on demand (and why not, also rain on demand).
Basically, given right mixture of humidity, temperature and “dust” infinitesimal water droplets aggregate to the point of becoming clouds (if the process continues you get rain/snow/hail depending on temperature).
Researchers, as an example, have noticed that ships sailing on the oceans live a plume of cloud behind them. This cloud, as shown in the picture, forms when the aerosolised sea water created by the movement of the ship mixes with the smoke produced by the diesel engines, smoke that contains a huge amount of tiny particles, fine dust, acting as magnet on the aerosolised water. The plume is shielding the water below from the sunlight. So, the researchers reasoned, can’t we do something like this and create a cloud blanket over the oceans? that would reduce the amount of sunlight, the water temperature, increase the adsorption of CO2 by the oceans…
Indeed, this is what researchers at NOAA are studying.They have received a 4M$ grant from the US Congress to look at how to use sea salt vapor to create clouds and at the university of Washington researchers are looking at how to use seawater to increase the whiteness of clouds, making them more light reflective.
At Harvard scientists are planning to take the idea of “clouding” to the stratosphere. Their idea, so far at the study level, is to use stratospheric balloons that can release fine dust of specific materials in the stratosphere. This fine dust would interact with high energy sun- rays altering the penetration of sunlight, basically creating a shield. The project, SCOPEX, Stratospheric Controlled Perturbation Experiment, is raising doubts and concerns (mostly on the “controlled” part) so for the time being it is taking place in small steps with the aim of increasing our understanding of the stratosphere. The goal is clear: be able to interfere with the amount of energy reaching the planet regulating it in time and location. If this would eventually become feasible, it would be possible to increase the energy reaching a certain spot whilst decreasing the one reaching a different spot. This unbalance would create winds and lead to rain. We would basically have a magic wand to create the kind of climate we want/need at the place we want it. As with any powerful technology (and this indeed would be the most powerful we have ever had!) there are plenty of risks and a lot of potential political turmoil, hence the concerns…
This is the birth of a new science, geo-engineering. Its proponents are claiming that even in the best scenario by 2050 we will reach a net zero carbon emission thus stopping the anthropic impact on the climate but this will not stop the climate change, since there are several other factors involved that are independent of human activities. Hence the need to develop a geo-engineering science that ultimately would all us to create the desired climate at the desired place at the desired time. Looks like an impossible dream, as it was an impossible dream to reach the Moon only a hundred years ago.
In between the control of climate by influencing the stratosphere and the creation of artificial clouds there are studies to place some reflectors up in the sky to divert sunlight so that it would not reach the planet surface.