A shaded sun-powered future for Earth

The huge decrease in sun-spot activity for the next few decades will be a big savior for us. See:

http://en.wikipedia.org/wiki/File:NOAAsourcebutnotofficialsunclimate_3b.gif

and

http://www.space.com/11960-fading-sunspots-slower-solar-activity-solar-cycle.html

Nice ! I guess good timing. 70 years would be more than enough (if it lasts that long) for humans to get rid of fossil fuel burning. But I wonder if we become a Type 1 civillization and convert most of the solar power on Earth's surface to heat, would that not be identical to reducing Earth's albedo, and thus cause global warming any way?

Well, it depends on whether the new panels' albedo is lower than the average albeldo of the area on which they are installed, which will surely be the case since they will be installed in a lot in sunny, sandy places.

I can see us having to setup some really serious cooling solution for Earth then. Basically if you are consuming 40% of sun's light as a Type 0.4 civillizaion, and those panels an albedo of 0.2, i.e. only reflecting back 20% of light, then you will cause an albedo to reduce to 0.2 from present 0.3.

However, the reduction will be bigger if all the areas getting replaced are bright deserty land which is the case.

As you can see here, the people who answered this very good question just were trying to be politically correct here: http://askville.amazon.com/solar-panels-Earth-retain-heat/AnswerViewer.do?requestId=5919445

True, for our current energy consumption, we will actually end up cooling Earth by using solar power as the alternatives heat up Earth even worse (every ounce of CO2 released by burning fuel stays in the atmosphere for millenia before plants and rain can scrub enough out). But I am talking about Type 1 civillization. Of course all energy in the galaxy comes directly or indirectly from stars and our solar system is no exception; all secondary sources such as nuclear, coal, hydel, wind are derived either from out Sun's solar energy, from from the star that came before (in case of Uranium for example). So a Type 1 civillization has nowhere to go but to become a solar power behemoth, consuming all of the energy it can coming down to Earth, plus some more in Space (on Mars, Moon, orbital stations, nearby stars etc.)

So getting back to how to fix this albedo problem for a Type 1 solar power civillization, which would be us in 100 years, if Earth ends up say absorbing 10% extra heat from all it gets, you would have to shade 10% of Earth to cancel that effect out.

There are several creative early 21st century ways to cancel this effect:

- Zero Albedo Reduction law (ZAR law- OK I coined it firt here on this blog!) for solar panel install: Require the land where solar panels are installed to have 0 overall albedo change. How it is achieved is left to the installer to pick from, e.g.:

- (a) a checker pattern of highly refelective white mirrors (albeo close to 1) alternating the solar panels, in proportion of the ground's albedo.

- (b) shine electromagnetic radiation vertically up in the night in a non-visual but transparent spectrum. This could be radio waves and source for free SETI transmitters back up :-) just kidding- pointing it back at the Moon's poles where the new colony sits would be fun too (again kidding but this could actually work), just kidding. Why would you just not produce less using (a)?

- (c) albeo trading: you could simply install new shiny rooftops in areas of the world where you don't need as much power for other areas where u reduce albedo. Of course this would still cause local climate changes- heating up areas of product, cooling down areas reflected- in fact (a) and (c) together can provide a way to engineer climate.

However, by the time we become a Type 1 civillization, by early 22nd century, we would have a more advanced non-early-21st century way of doing the above :-) A checker pattern robotic self-maintaining and producing asteriod material based solar sun-screen parked in an orbit 1 million or so km away from Earth towards the sun (one of the lagrangian points I believe), and reduce solar insolation to Earth as needed.


Cheers,
Gunjan