Macroeconomist Jeff Sachs, Director of the Earth Institute Columbia University and Assistant Director to the United Nations Attorney General, has been saying for at least eight years that there is a dirty little secret among many of the well-off that “Yes, high mortality rates are awful, but they do help keep the population explosion in check.”

His response has been that while it may be counterintuitive this idea is totally incorrect and that very high infant mortality helps accelerate the population explosion since the extreme poor way over-compensate with very high fertility rates in the hopes that they will somehow survive in their very difficult and unstable world. It is only until they become very secure in their world such as through considerable poverty reduction with subsequent stable low infant mortality rates that the fertility rates substantially decrease accordingly.

The Jeff Sachs quote posted above (15. gecko) addresses everything you’ve mentioned except the “Population Momentum” you describe at the end which he talks about on page 169 of “Common Wealth”, in the chapter titled “Global Population Dynamics”:

“This is our situation in the world today. We are at 6.6 billion people. If somehow, miraculously, the TFR (total fertility rate) were to fall today to the replacement rate, the world’s population would still grow by approximately another one billion (depending on the precise assumptions made). We would end up with a planet of 7.5 billion. That’s true even with the co-called baby bust in the more developed regions. In the coming decades, the momentum of population growth in the developing countries, with their very young population, will simply overwhelm any tendency to population decline in the high-income countries. This is why, in essence, we need to be working much harder to reduce the fertility rates in those regions, for their benefit and for the world’s.”

-- “Common Wealth”, Jeff Sachs page 169.

The following is an expansion on the already posted excerpt “There is nothing automatic about the transition of fertility following a decline of child mortality”:

“One key question, which derives the policy judgments of the next chapter, is why the decline in fertility lags behind the decline in mortality, and what can be done about it. There are three kinds of answers, all contributing to a realistic picture. First, fertility choices are built into the culture. The age of marriage, the social expectations of the number of children a family should have, the beginning of the childbearing age, the use of contraception, in the birth spacing, and the like, are cultural as well as economic choices. Societal norms and expectations play a role in determining the choices. Even when the fundamental determinants of fertility choice change – for example, a steep drop in child mortality – the resulting change in actual fertility practices might take a generation or more.

“Second, there can be a recognition lag, during which the parents are unsure the child mortality rates have really declined. The parents maintain high fertility rates just to be sure. Once the reduced mortality is firmly believed in, the fertility decline picks up speed. Third, and perhaps most important, there is nothing automatic about the transition of fertility following a decline of child mortality. Fertility choices represent the active decisions of households (including differing views and interests of fathers and mothers). The continuation of high fertility rates in the face of falling mortality rates might reflect a rational calculation by the parents, given the socioeconomic conditions of the household. When families live by subsistence farming and children provide labor and old-age security, and when the mother and daughters have few alternative means of livelihood, high fertility rates may be accepted as the preferred option for women, or at least the decision imposed on them by their husbands and the community. Moreover, contraception may be prohibitively costly for a family living at substance. Health care and family planning advice may be nowhere to be found.”

-- “Common Wealth”, Jeff Sachs pages 172-173

Gecko, there is no evidence that human reproductive strategies are rational, even in developed countries. So you won't get anywhere by philosophizing about what a hypothetical rational couple might decide to do. Otherwise, why would you continue to have children even while suffering from famine? Rape (inside or outside marriage), war, religious and cultural factors, education, access to contraception, and plenty more besides have a huge impact on birth rates regardless of infant mortality. See e.g. here for a discussion. In Sri Lanka it took 15 years before the drop in death rate shows up in the birth figures -- and about 40 years for the birth rate figures to catch up completely.

Finally, demographic trends mean that the population growth rate can continue to rise even as fertility rates fall, because more and more people reach puberty every year. This is exactly the situation in Africa: In Uganda, for example, fully 35% of the population is under 10 years old. As those children enter puberty, the population is only going to increase, even if the fertility rate were to drop to developed-world levels.

The Kyoto agreement, and the opposition to it, was based on the premise that the developed world had created all the global warming problems, and the developing world was not being asked to do anything to help solve the problem.

Each of these arguments is, in a way, false. If you assume that all people have an equal right to (eventually) tax the environment, overpopulation is an environmental problem. And the developed world has been hassling the developing world to cut its population growth for 40 years.

Since 1968 or so, how does the progress of the developing word on population growth compared with the progress of the developed world on per capita emissions? I think they've done more for the planet than we have thus far.

The simple answer might be that when mortality rates plummet from a very high value to a much lower value, say for example, 20 percent to 3 percent total fertility rates will also tend to plummet since high fertility rates probably no longer make sense.

My apologies for posting below economist Jeff Sachs longer explanation:

“Suppose that children are the main old-age security for their parents, especially in the countryside. To ensure that old-age security, the household would like to ensure a surviving son with a very high probability, which we’ll put at 97 percent for purposes of illustration. The household then chooses the number of children needed to ensure at least 97 percent chance of a surviving son. If the probability is one in five (20 percent), then having one son only won’t be enough to ensure a 97 percent survival rate. The chance of a single son surviving is only 80 percent, not enough for the parent’s security. Having two sons is still not enough. The chance that both would die would be 20 percent multiplied by 20 percent, or 4 percent (if their survival probabilities are independent of each other). The chance at least one surviving son would therefore be only 96 percent (equal to 100 percent minus 4 percent).

“Having 3 sons would do it. The chance that all 3 would die would be 20 percent times 20 percent, or 0.8 percent. There would be 99.2 percent chance that at least 1 of the sons would survive. For families to have 3 sons, they would need, on average, to have 6 births, half girls and half boys. A child mortality rate of 20 percent (200 deaths per 1,000 births) would therefore induce a TFR (total fertility rate) of 6 in this illustration. The population would soar. Of the 6 children, 4.8 would survive on average (since 20 percent of the 6 children, or 1.2 children, would die). Each mother would be raising 2.4 girls (on average). The population would more than double each generation!

“Now consider the implication of a drop of the child mortality rate, from 20 percent to 3 percent (thirty deaths per one thousand births). In this case, the chance of a son surviving is 97 percent. The parents will be satisfied to raise one son or just two children on average. The TFR (total fertility rate) will be two, and the population will be stable. (Actually, in this example it would decline slightly, since only 97 percent of the daughters would survive, and the net reproduction rate would be 0.97).

“Now here is the implication: a drop in the child mortality rate must be large enough to induce the risk-averse parents to cut back on the number of children. If the mortality rate is three hundred per one thousand births, they will choose to have six children (for reasons just argued). If the mortality rate drops from three hundred to two hundred per one thousand, they will still choose to have six children. The population growth rate will speed up, without a decline in the fertility! If the mortality rate drops further, to thirty per one thousand, the parents will choose to have only two children.” Common Wealth, Jeff Sachs page 173-174

However, most of the world has already moved to the model of lower birth rates, longer life spans, and less infant mortality. Africa still has the old model of high birth rates, short life spans, and high infant mortality, but almost all of the rest of the world no longer does.

Hey why not? I'm 46, and was 18 to 25 at the height of their career, right? Rush, Kansas, etc.

I'm not trying to be callous here, but how do you figure that reducing infant mortality is going to reduce population?

No disagreement from me. But for those who think of themselves as the "little people" in the United States, those aren't even people.

The "little people" are the approximate two billion global poor starving to death with less than 40-year life expectancy and living excruciatingly difficult lives with very high birth rates to compensate for very high infant mortality leading to a target peak population of something like 9 to 10 billion about midcentury.

Greatly lowering infant mortality with poverty reduction could potentially reduce the peak global population at 2050 to about 8 million and provide a huge reduction of emissions.

Eliminating deforestation is another example of how countries have to work together and will save about 25% in yearly CO2 emissions immediately.

World-class cities will eventually lose their status if they do not adequately address the climate change crisis.

Sprawling on the fringes of the city
In geometric order
An insulated border
In between the bright lights
And the far unlit unknown

Growing up it all seems so one-sided
Opinions all provided
The future pre-decided
Detached and subdivided
In the mass production zone

Nowhere is the dreamer
Or the misfit so alone

Subdivisions ---
In the high school halls
In the shopping malls
Conform or be cast out
Subdivisions ---
In the basement bars
In the backs of cars
Be cool or be cast out
Any escape might help to smooth
The unattractive truth
But the suburbs have no charms to soothe
The restless dreams of youth

Who needs a house out in Hackensack?
Is that what you get with your money?

It seems such a waste of time
If that's what it's all about
Mama if that's movin' up then I'm movin' out.

Why young people flee the suburbs was the underlying question of the day. But there has never been much mystery about it: There is nowhere to live; not enough to do; and not enough young adults around to improvise the kind of neighborhood scene born every few years in the big city.

Maybe instead of "Downtown," they should have played the Velvet Underground's "Rock and Roll," which described this problem:

Two TV sets and two Cadillac cars
Well you know ain't gonna help me at all

Here's a money-saving idea for the New York State DOT: Decomission the Sheridan Expressway.

Thanks, Vnm, I've added it to my spreadsheet o' boondoggles. Estimated savings: $200 million - but that was before the cost of construction skyrocketed.

The state DOT could also save about $11 billion by refurbishing the Tappan Zee Bridge instead of replacing it. But then they wouldn't be able to add three car lanes.

All we need is for fossil fuel prices to stay high, and no one will need to "think big" on their behalf. They'll figure things out themselves.

Our problem is that when we start to conserve and invest in alternatives, the energy price drops, and everyone who does so becomes a "loser" and a "fool." And people go back to the easy way.

If the price of oil had stayed at its current level from 1980-81 to today in real (inflation adjusted) dollars, instead of plunging to all time lows and then soaring again, we wouldn't be in this fix.

re: Climate Bill Voted Down (Grist, Carbon Tax Blog)

Here's one on the exurbs.

http://www.bloomberg.com/apps/news?pid=20601109&sid=a4kOXcpI3dQg&refer=home

``At $4 per gallon gas, $125 per barrel oil and $10 per million Btu natural gas, a lot of activity becomes uneconomical,'' says Mark Zandi, chief economist at Moody's Economy.com in West Chester, Pennsylvania.

"The lifestyle of the exurban commuter may be one casualty."

So much for the folks who chose conservation as a matter of "personal virtue" being losers in the marketplace. We'll see if politics can reverse that verdict.

Let's see if our Democratic representatives can engineer an "inadequate energy use tax" on us in pursuit of political advantage elsewhere. Perhaps Brodsky and Weiner can propose it, along with more placards and service cuts at the MTA.