There are other options available, like having people carpool and planting trees. If we work together, we can make it so there’s enough stuff to go around. Starting sooner means it’ll be easier. Besides, killing people wouldn’t solve any problems – our population would just grow again and we'd have to deal with it later.

If there were no other options available, then killing people would make it so we emit less carbon dioxide and thus reduce global warming.

According to the best scientific estimates out there, global warming will increase sea level by at most a few meters over the next century. Some sea walls will have to be built, some people will have to move, some extra effort will have to be made to preserve some species. But it's just not as big of a deal as Al Gore wants you to believe. It's not the end of the world, and it's certainly not nearly enough to justify killing ANYONE, let alone half the planet's population.