Should There Be A Blackout For One Year To Help Stop Global Warming?

Bad idea. Too many people would die- and if you're saying something along the lines of "oh, well, they're just PEOPLE, it's not like they're dolphins or something important", then congratulations: This is why you will never be allowed into a position of authority over the lives and deaths of people.

lets put it this way: The harvest, in most at least partially developed countries, has been mechanized. With a blackout, there's no way to get the harvest done in time (not even if you pull all the people available in and make them do it), and so the food rots, the people starve.  Even in countries where the harvest is *not* mechanized, there is not enough variety of local produce that can be transported, and so you end up with food shortages there anyway, because they ship the durable produce off to different areas in exchange for other goods or services (basic economics) but the other goods have to be durable as well, or they won't survive the journey.  This is just between cities, I'm not even going to get into what has to happen for inter-continental trade to happen. What do you want to happen? Sailboats? Triremes? Viking long ships, full of potatoes, rowing across the pacific ocean to bring potatoes to hawaii, or japan?

or you could look at the medical equipment necessary to keep lots of people alive.  Forget people on life support- just think of aspirin. With a global blackout, there would be no medicine produced (homeopathic medicine doesn't count- because it isn't medicine- and most of chinese medicine and indian medicine are a joke. Some of it works, yes, but a lot of it does a lot more harm than good) means people who would otherwise take a pill and heal from a cold will possibly die from that cold.  I know you think that there's a lot of extra medicine, but think about this: Most medicine has an expiration date of within 18 months, and the manufacturers of this medicine don't make a lot at a time, because they wouldn't be able to sell it all and it would go bad and cost them money. It's a very fine-tuned system based on years of observation of different trends. If you suddenly pull the plug on this, the machine is off, all the medicine that exists is all that there is, period, and in a world *full* of people competing for this, it's going to get very expensive just at the start and by the end will probably be violently fought for- resulting in more loss of life.  This is exacerbated by the fact that some drugs are kept in deliberately short supply to keep the price up.