The point is not only about over-population but about the extortion that passes for office collections. I really get tired of being asked to contribute to the baby showers of women at work I hardly know. I don't see the need to contribute to their lifestyle decision unless maybe they want to contribute to mine when I decide to adopt a new kitty.
This being a Dilbert comic strip, I think the coercion to pay for other people's personal choices in the office place is the main message.
Before health-care (and arguably modern farming* ), you needed six more children because only two out of six survive and often you are providing replacements for your brothers and sisters. With better standard-of-living and education couples tend to go for quality, not quantity with their children - they don't need their children for labour and income. Society needs young people, hence children to pay for the old people.
* Adequate food is as affective (more so) as good medical/medicine, to a populations health.
Whether you believe in global worming or not, it's an amusing strip about keeping things in perspective. That's an incredibly hard thing in this topic. What's objective to you is biased to someone else.
Dilbert is just being sarcastic. As an intelligent engineer [I guess that's tautology] he knows that human activity has a minisule effect on global climate, whereas the general public, including Kim, are usually "informed" by the MSM. Taking care of the environment is another matter (being "light green"); hopefully we can all agree on that. Scott Adams apparently does - see http://online.wsj.com/article/SB10001424052748704868604575433620189923744.html?
PS To categorise CO2 as a pollutant (as some do) is a stretch - unless O2 is also a pollutant.
I never smile when dilbert is on a "Liberal Day"
I smile less when he makes fun of the family
Dilbert as a character is also inable to make political decisions, he looks at everything through science. I always view Dilbert as far smarter than anyone alive, but even I see that man-made global warming does not have much hard science in it. Either dilbert just made a decision based on emotional response, or he blew past the scientific method...