If I = PAT, then what can we do about P?

October 27, 2014 3:32 PM

Human population reduction is not a quick fix for environmental problems, at least according to Professors Bradshaw and Brook in the latest PNAS, arguing from a population biology perspective that we are guaranteed a very large total human population for centuries, even inclusive of radical fertility changes. Pr Bradshaw provides more informal/accessible commentary on the paper on his blog.
posted by wilful (11 comments total)

I wonder what their model would look like with a natural mass extinction event, like a meteor impact similar to what triggered extinction of the dinosaurs. A quick scan of the 'net seems to suggest that it took 33k years after impact (along with the long-term temperature swings that followed — perhaps more extreme than the climate change scenario described in the PNAS paper) before the dinosaurs were effectively gone.

Perhaps a technology-augmented species like humans might indeed be able to survive and recover from such a catastrophe, let alone modeled scenarios of lesser scales, which are largely or entirely man-made (climate change, pandemics, global wars, etc.).
posted by a lungful of dragon at 3:56 PM on October 27, 2014

From the abstract:

However, society’s only real policy lever to reduce the human population humanely is to encourage lower per capita fertility. [...] Even a catastrophic mass mortality event of 2 billion deaths over a hypothetical 5-y window in the mid-21st century would still yield around 8.5 billion people by 2100.

(Emphasis mine.) There's the problem; the author is concerned with issues of humaneness, and also thinking too small. How about a mass mortality event of 6.5 billion? Would that do the trick?
posted by Faint of Butt at 3:58 PM on October 27, 2014

Sterility plague?
posted by BrotherCaine at 4:19 PM on October 27, 2014 [1 favorite]

The trouble with catastrophic mass mortality events is how many times you have to try them to get one to start in Madagascar.
posted by delfin at 4:19 PM on October 27, 2014 [1 favorite]

Yes, since when do we want scientists that consider things humanely? With such lily-livered thinking Aperture Laboratories would have never gotten off the ground. (Actually, Figure 1 does model a mass mortality of 6 billion people, which leaves about 5 billion in 2100.)

The most interesting thing to me here is the "no unintended pregnancies" line. A nice slight peak mid-century, then curving down. Yet another strong argument for easy access to birth control and for education for women.

The framing of the situation is a bit odd, i'm not sure that population reduction is viewed as much of a quick fix as an eventuality that reduce human impact. And even though there's no quick humane way for overall population reduction, the alternative is somewhat shocking. As in the blog post, if impact is populations times affluence times choices, then that's not a reason to avoid it. Better to keep population constant and work improve the choices we make so that environmental efficiency improves by 30%, then to get that same improvement and then increase the population.
posted by Llama-Lime at 4:26 PM on October 27, 2014

A note on the authors (both of whom I have worked with in the past) - Brook is a bit of a utopian techno-ecologist, who advocates a transition to intensive dense human settlement, with energy provided by nuclear power, and a retreat from extant "natural environments" in order to give nature its own undisturbed place. Which is, to say the least, a fairly controversial opinion.
posted by Jimbob at 4:28 PM on October 27, 2014 [4 favorites]

What's funny is you need to do a whole bunch of paperwork to get a licence for a gun, but it's okay to fire out kids left and right (and own pets, for that matter). A child born into a relatively affluent country like Australia is going to do more damage to the planet than a child born in, say, Chad, especially if it is a gun-faced child, that shoots bullets when it cries. Anyway, my point is, we need child licencing, and you should have to do some kind of years-long course and get a Degree in Raising Children, and another good idea is to ban $2 shops, because Jesus.
posted by turbid dahlia at 4:42 PM on October 27, 2014

Anyway, my point is, we need child licencing, and you should have to do some kind of years-long course and get a Degree in Raising Children

What I want to know is, what are the assessment criteria? What do you need to do to pass the course and get your kid licence? Tigercopter parents need not apply?
posted by Jimbob at 4:48 PM on October 27, 2014 [1 favorite]

Well that's easy then.... breeding licenses will work SOOOOOO well across all cultures and nations /babyburger
posted by lalochezia at 4:49 PM on October 27, 2014

What I want to know is, what are the assessment criteria? What do you need to do to pass the course and get your kid licence? Tigercopter parents need not apply?

Not that I'm advocating it, but it wouldn't be that hard to develop an objectively assessable "are you competent to look after the basic physical needs of a baby" test. And a very basic bit of psychological guidance/counselling.
posted by wilful at 4:54 PM on October 27, 2014

Not that I'm advocating it, but it wouldn't be that hard to develop an objectively assessable "are you competent to look after the basic physical needs of a baby" test. And a very basic bit of psychological guidance/counselling.

If you pretend it would be easy, you're advocating it.
posted by michaelh at 4:59 PM on October 27, 2014