To celebrate Earth Day, we'll be running some environmentally-themed pieces. I got excited when the topic came up because it meant I could talk about one of my favorite sci-fi flicks, 1972's Soylent Green. I think it's safe to say that everyone knows what the secret ingredient in Soylent Green is at this point, but this glimpse into the future (it's set in 2022) turned out to be amazingly prescient in some regards, highlighting many of the environmental issues we're currently facing. Charlton Heston stars (sporting some killer duds) as Robert Thorn, a cop who becomes embroiled in a case much larger than it first appears. What looks like a simple death transforms into something bigger and more ominous. As events progress, Heston's character morphs into a futuristic version of Al Gore, Ralph Nader, and Morgan Spurlock -- with a badge. Sure, the technology looks dated, but the story is reminiscent of the best sci-fi, presenting fantastical ideas and concepts that have a direct link to our everyday lives. You can learn a lot from Soylent Green. Jump past the break and I'll share five things the film has taught me.