To become masters of this unpredictable thing that is weather is something that only sci-fi has been able to create.
Imagine a world where there wouldn’t be no more extended droughts, floods, blizzards, El Niño or hurricanes. Climate would be mild all year across (still allowing seasonal variations), with scheduled rains timed for maximized agriculture.
Perhaps more important than that, lands that fall now under the low precipitation zones could suddenly become productive and give rise to prosperous urban areas.
One important distinction that must me made is that there is climate and there is weather. Weather is the very unpredictable, short-term trends in atmospheric conditions. It’s ‘ruled’ by the same kind of rules of a lottery game. Climate refers to the (predictable) long term trends of those conditions in a region, averaged over a time frame.
Unfortunately, this distiction is often forgotten in those who denial climate change. A commonplace argument is that you can’t make statements about the climate because it’s unpredictable (but that would be weather). What is true indeed is that it’s not simple to make assessments about climate. It’s still one of the most poorly understood fields of science – as it should be with dealing with planet-scale complex systems.
Because it’s so poorly understood, you probably shouldn’t mess with climate. But we will ignore this advice for the fun of it.
If you had to choose one to have absolute control, you would pick climate. As much as you might want the rain not to ruin you sunday barbecue, you would want more to have enough food for the next generations.
Researching a climate modification system should be viewed as an investiment. Consider for a moment the material cost of hurricanes. According to one source, Katrina (2005) alone costed $ ~106bi in damage. Losses in agricultural production probably mount billions per year in the US alone. To prevent only a fraction of these losses with some investment could prove worthwhile.
The truth is that, as of now, there is no known technique that can deliver all that has been promised above. The best thing we could do is to prevent things from getting any worse, by compromising and making the damned lifestyle changes.
The closest I could find to a climate modification is called cloud seeding, a process to artificially create rain when desired, by seeding a cloud with selected chemicals. It’s controversial, and dangerously close to hocus pocus. Apparently China is one of the leading powers in this enterprise, and has been doing it for quite some time.
Another proposed solution for climate change is to install space mirrors, obstacles to sunlight, in space. They could be used to reflect some of the light and reduce warming. If we could have control over what areas would be shaded (what is considerably more challenging) we could in principle engineer the climate of Earth.
Let’s tackle a small part of the challenge here. Cloud seeding uses water that is already in the atmosphere. But that is not always the case.
Could we heat enough water to make a rain?
We will answer the question on the basis of whether the energy used, or power, is within what our civilization produces. There are technological or practical issues that are not covered here. We will also be making a number of guesses.
The energy is:
Suppose the rain falls over an area A in m2 with E millimeters. If we imagine a box with a m2 the height of the water collumn would be E mm. So the mass of water is
Plugging it into the other equation, and using the values:
The area used is not that big. It’s the area of Madison, Wisconsin. I picked it because it’s very dry but surrounded by water bodies.
That’s a lot of energy up there. Heating water is very energy consuming. To put this number into a perspective, lets say we are building a rain in a week, or 6.048E+5 s. The power required is then: 6.36E+8 W. Comparing to one of the huge hydro powerplants, it’s about 4.5% of it’s maximum output.
So it would seem, at first glance, that if we wanted to build ‘boilers’ to heat water into the atmosphere it would be within our grasp. Dedicated power plants (moved by renewable sources) built to boil water, on locations where the water would be carried into a desired target site by winds.
If the water would effectively go where it’s supposed to, or if it would disperse into the atmosphere is a whole other history. Probably not every location is suitable for this, as a deep understanding of the particular wind patterns is required. Ultimately, you could add an effective factor from 0 to 1 into these calculations. If this factor is too small (say <0.01) it renders this idea unpractical.
If you placed several boiler units at sea along a typical wind route, hoping to be more moisture left for the air masses inside the continent, you would probably end up with increased rainfall along the coast line too. That could or not be inconvenient, depending on case. These units are supposed to be central controlled and only turned on when necessary. It’s implied that they are, somehow, more efficient than natural evaporation.
Another alternative for heating water is a sun gun (remember Die Another Day?). How would you reposition a 10km2 mirror with ease I really can’t say.
Making not rain when desired, on the other hand, seems quite harder to imagine. That is unfortunate, all evidence points out to a general increase in precipitation with climate change.
[IMAGE: ‘Bad’ weather over a urban area, unkown location.]