[dmritard96]

"Population growth has been slowing since the late 60's, it peaked in 1968."

Misleading phrasing...

"World population projected to reach 9.7 billion by 2050. The current world population of 7.3 billion is expected to reach 8.5 billion by 2030, 9.7 billion in 2050 and 11.2 billion in 2100, according to a new UN DESA report, “World Population Prospects: The 2015 Revision”, launched today."

http://www.un.org/en/development/desa/news/population/2015-r...

[throwaway5752]

Yeah, comp sci 101 alone is sufficient to know that logarithmic growth's second derivative is negative for all x > 0, and ln(x) is still unbounded. "Growth is slowing" can be a very effective sleight of hand.

[overcast]

Slowing does not equal stopped.

[Retric]

It also does not mean it's going to stay under a limit making it a poor yardstick. As throwaway5752 said, the limit of log(x) -> infinity is still infinity even if it starts growing really slowly.

Really though we don't need to kill / sterilize all humans, getting off the planet could work just fine.

[overcast]

Sorry, when did anyone talk about a limit? If the slowing growth continues, then eventually it will cross zero into the negative. Look at the relative growth, by 2100 it's predicted to get close.

[Retric]

> If the slowing growth continues, then eventually it will cross zero into the negative.

Err, no. The growth of log(x) is always decreasing and yet it always stays positive. This is true for a huge range of functions and one of the reasons limits are important.

Now, you can argue that the way human growth is slowing suggests it might possibly go negative at some point. But, that's less obvious.

[overcast]

You're trying to impress us with the maths. I already took all of the statistics, and differential equation classes twenty years ago. I get it. However, there are already countries experiencing negative population growth, and the trend is continuing in other Western countries.

[Retric]

I am not trying to impress with high school math, I defending someone that got down voted for an accurate statement.

At best we are predicting a peak human population 30+ years from now and those kind of predictions are never very accurate. Further, even if that's one peak it says very little about human population 100's or 1,000's of years from now.