Babies! They use so much energy that the best thing you could do to save the human race from climate change might be to avoid having one altogether. But if you choose the reproductive path, at least the 6,000 poopy diapers that your offspring will produce in the course of his or her early years could have a second life as part of your house — specifically, as the shingles tiling your roof.
The diapers, thank goodness, are sterilized first. Then they’re separated out into their components. The, um, "organics" go to waste-to-electricity products, and the plastic part goes into roofing tiles. So it's not like you'd literally be living in your kid's waste. But close!