Posts Tagged ‘economic growth’

Where are we going?

August 28, 2010

In the previous post I showed some global maps with the countries’ size scaled according to their population, GDP and GHG emissions. GHG emissions scale very strongly with GDP, and as Tom Fuller noted

That is the dilemma. It is not the number of people, it is their developmental status and desire to live a modern life.

As a follow-up, look at these maps, where countries are scaled according to their GDP, with a sneek preview to what the future may have in stock:

These projections show world GDP growing over the course of the century, with the most pronounced growth in developing nations. The 2100 map resembles the area weighted “normal” map much more than the 1990 map does, signifying a more equitable distribution of global GDP. I regard that as more fair than the current distribution. (After all, why would some people have more right to the world’s riches than others?)

But if you take into account the strong relation between GDP and CO2 emissions (and other environmental impacts), the scale of the challenge becomes clear:

  • Either the emissions per GDP have to dramatically decrease by using less energy (reduced energy intensity of GDP) or by using sustainable energy (reduced carbon intensity of energy).
  • Or GDP can not grow in the way projected in these figures (at least not without creating huge problems with natural resources, climate and -as a consequence- geopolitics).
  • Or we let it run its course and let future generations deal with the consequences of our (in-)actions (as described just above).

To me these options are ordered in decreasing order of preference. Paraphrasing John Holdren in a different context: We’ll probably do all three; the question is what the mix is going to be.

The last option also underscores that “the problem is that it’s not our problem”.

Those who caused the problem are not the same as those who will carry the burden.

Figures from Naki Nakicenovic via a thought provoking presentation by Ken Caldeira.

What does population have to do with climate change?

August 23, 2010

Population may not be the driving force behind many of the global world problems, but it’s certainly important: Basically, it is a multiplication factor for the environmental impact of certain actions. E.g. better environmental performance of some products has occasionally been offset by its much greater use (cf. population density). Of course, if a real innovation comes along, the environmental impact could be cut more drastically (which also happens, but counting on it may be risky).


The 20-80 story puts population in perspective: 20% of the world population uses approximately 80% of the worlds’ resources (dependent on the resource of course). That alone means that focusing on population isn’t where the shoe pinches in many cases: It’s the (over-)consumption in the rich areas that causes the most strain on the world’s resources.


On the other hand, I’ve understood that the reason that native cultures had relatively little impact on their environment is to a large extent due to their small population density. Burning a small piece of forest to use the land for food production may not be a great problem for the ecosystem if it only occurs sporadically, thereby not causing more disruption than the ecosystem can handle. It only becomes a problem when the magnitude increases above sustainable levels, which is intricately linked to population. There are plenty of examples in nature where too large numbers of a certain species causes stress on the ecosystem.

The Kaya identity shows that population is a multiplication factor, just as consumption is:

CO2 emission = population * GDP/capita * energy/GDP * CO2 emission/energy.

It would require a systemic analysis to see which factors are most responsible for a given problem, but it’s pretty clear that population is a factor that influences the total pressure on the system. The 80-20 ratio described above shows that consumption patterns by the rich cause the most strain on the world’s resources. I’d wager that the difference in consumption patterns between different parts of the world is (a lot) larger than the spread in population density, which would make the former most important. Population is not a factor that is easily or quickly influenced, but for the long term, it should be seriously considered as an important factor (especially because it has so much inertia).

Pointing fingers solely to, or firmly away from population, both misses the mark imho. reality is not black and white.

Greenhouse gases

How many people the earth can sustain of course depends on the other factors in the various Kaya identities: If everyone were to have the consumption pattern of an average American, we would already have overshot the long term carrying capacity of the earth. If we all live a Buddhist lifestyle, we could probably do with a few more people. It’s a trade off, as always.

Don’t want to use (and pay for) sustainable energy (cf consumption pattern)? Then use less energy (cf population).

Don’t want to use less energy? Then use (and pay for) sustainable energy.

Don’t want to do either? Go find another planet.

This leads to a major moral dilemma: Developing nations also want to increase their material welfare, but them doing so by mimicking our current ways of production and consumption is a recipe for disaster. OTOH, we have no more moral right to the earth’s riches as they do. Something has to give, obviously.

See also this thought provoking article by Michael Tobis, where he takes on the other, even bigger taboo: economic growth. Bottom line:

A given economic growth rate can be sustainable only if the average impact per unit wealth declines at an equal or greater rate.

I.e. if the carbon and energy intensities decrease at least as fast as the GDP increases.

Attempting to reach equitable economic prosperity and allowing for normally projected increases in GPD and population, Tobis estimates that the impact per unit of wealth has to decrease roughly 50 fold by 2050.

(Figures from Newman. Post based on a comment of mine over at Kloor’s blog)

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