40% CO2 Reduction

[TimBikes]

"population aging reduces long-term carbon dioxide emissions, by almost 40% in a low population scenario, and effects of aging on emissions can be as large, or larger than effects of technical change in some cases."

See link...

I guess the idea is that old people don't consume as much or drive as much as young people. Hmm.

[silentak1]

<div class='quotetop'>QUOTE(TimBikes @ Nov 15 2006, 12:57 AM) [snapback]349359[/snapback]</div>

I guess the idea is that old people don't consume as much or drive as much as young people. Hmm.
[/b]

Geez, 38 pages. Without reading a single sentence in the file I can agree with your quote. Young people drive anywhere, for any reason, with often disregards for "efficiency" (multi-trips). Well, everyone tends to do that once in a while.

[Tempus]

I think it may be accompanied by an increase in Methane Emissions though.

[chogan]

<div class='quotetop'>QUOTE(TimBikes @ Nov 15 2006, 01:57 AM) [snapback]349359[/snapback]</div>

"population aging reduces long-term carbon dioxide emissions, by almost 40% in a low population scenario, and effects of aging on emissions can be as large, or larger than effects of technical change in some cases."

See link...

I guess the idea is that old people don't consume as much or drive as much as young people. Hmm.
[/b]

I wouldn't make much of those results. In fact, I'd go so far as to say that the "40%" figure in their "low population" scenario is almost complete baloney. I have the advantage of being an economist myself, so I get to read a lot of baloney like this, which makes it easier to spot.

First things first. Take their actual consumption data by age group. That's tables 1 and 2, and that's the only hard data in the entire exercise, because that's the same data source that's used to calibrate the Consumer Price Index.

If you just take those tables and do the arithmetic for two big energy categories, utilities and fuel (which in the CPI means gasoline and diesel), multiply share of consumption x total consumption $ per capita, you find that older people spend a lot more on utilities than young people (bigger houses, duh), and everyone except the very oldest old spends more on gasoline than than young people.

So, maybe younger people drive more, but geezers have bigger cars, more disposable income, regular jobs that require commutes, family vacations, and, at some point, a lot of time on their hands. Whatever the reason, empirically, total consumption of motor vehicle fuels only falls off after age 75, and total utilities spending by the elderly is always higher than for younger people.

So, how in the heck do you get a 40% reduction, out of those data, based on their "low population" scenario?

Well, you sure don't do it with a simple weighted average of the data. If I take current consumption patterns by age (Table 1 x top line of table 2), and accept their horrific "low population" scenario that generates the 40% figure (Table 3, bottom, in which the US population dies back from 300 million now to 250 million in 2100, and accept the horrendous resulting age shift, I find that total utilities plus fuel spending at the current age distribution would be $1004/capita, and at the assumed 2100 age distribution, it would be $1105/capita.

In other words, the raw data say that aging of the population would increase total spending for direct energy purchases (utilities and fuel), because older people have much higher utility bills, and only start to reduce gas consumption after age 75.


In fact, they even friggin' say that, on page 10, for crying out loud, then roll right along with their modeling.

"Since the most energy intensive goods are utilities and fuels, expenditure
patterns in Table 1 imply that aggregated consumption in older households is more
energy intensive than consumption in younger households.:

So, my calculation and their writeup both say that older households have higher direct energy purchases than younger ones. So, the raw data say that an aging population will use more energy, not less, per capita.

Well, as an economist, I can tell you what that means. That means that their "40% reduction", under that horrific "low population" scenario, is being generated by the the mists and smokes of their model of "intertemporal optimization" that fills up the middle of the paper. I've seen that sort of thing before. And it's generally not worth the paper its printed on. It's anybody's guess as to what that model actually does.

So, this is baloney. Baloney 1 is citing the result that assumes a population die-off in the US from 300 million to 250 million. Baloney 2 is that the only hard data in the paper show that older housholds have higher direct energy purchases per capita than younger ones, so the simple calculation shows that an aging population would, all other things equal, have higher per capita energy use. Baloney 3 is that, after acknowleding that, somehow their results are mystically generated by their model of intertemporal optimization (which is typical academic economics baloney), but they don't even bother to explain how their model produces this clearly counter-intuitive result.

So, one's faith in this figure rests in one's confidence that some academic economists' sophisticated modelling of intergeneration tranfers of wealth and consumption, under the assumption of a US population die-back, is more credible than doing the simple math from the two tables of hard data presented in the paper. I'll go with doing arithmetic from the data.

[TimBikes]

<div class='quotetop'>QUOTE(Tempus @ Nov 15 2006, 08:05 AM) [snapback]349500[/snapback]</div>

I think it may be accompanied by an increase in Methane Emissions though.
[/b]

[TimBikes]

<div class='quotetop'>QUOTE(chogan @ Nov 15 2006, 08:11 AM) [snapback]349506[/snapback]</div>

I wouldn't make much of those results...
[/b]

Man chogan - you've got a lot more time on your hands than I do!

So I'm wondering what your perspective is on the IPCC economic model assumptions that lead to their projection of a 1.4 to 5.8°C temperature increase by 2100?

The "fantastic" assumptions aren't received very well by some economists - they've been called "an insult to science" and "an insult to serious analysis" and it has been suggested they include deliberate use of inappropriate exchange rates and "unbelievably high" growth rate assumptions...

See here: