Another Look at "The Limits to Growth"

http://www.smithsonianmag.com/science-nature/Looking-Back-on-the-Limits-of-Growth.html

by inetsee • 14 years ago

32 34 14 years ago

smithsonianmag.com

api• 14 years ago

I'd say right now that everything looks great -- very optimistic -- unless you look at two areas: energy and politics.

If you look at energy and politics, everything looks apocalyptic.

ChuckMcM• 14 years ago

I'm not so sure about the energy side, we've got a number of folks who are making real progress in both solar efficiency and energy storage. We have new nuclear processes that were once derided (cold fusion) being quite durable (while most folks don't have a good explanation about what is happening, more and more of the community is convinced that something we don't know about is happening at these low energy levels) We are getting hints of some of superconductivity's secrets which has the potential to eliminate distance constraints on energy transport, and we know how to build nuclear plants that are walk away safe and can consume their own waste leaving behind some easily manageable and easily containable waste products.

kragen6• 14 years ago

> more and more of the community is convinced that something we don't know about is happening at these low energy levels

[citation needed]

I agree with the solar-efficiency and energy-storage points, though.

aqme28• 14 years ago

"We have new nuclear processes that were once derided (cold fusion) being quite durable"

I'm sorry but this statement is completely false. Cold fusion is not taken seriously almost anywhere, much less is it considered "durable" by anyone including its fiercest proponents.

edit: Even so, many of the most promising new energy technologies (superconductive transmission lines not being one of them) aren't on track to be viable or disruptive by this 2030 'disaster.'

kiba• 14 years ago

Energy no object, it's a matter of harvesting it and dissapating the wasted heat.

After all, the sun send more energy to the earth in one hour than we use in an entire year as humanity.

adamc• 14 years ago

Mmm, that's kind of hand-waving away the hard part. In practice, that has been hard enough that energy generation is an issue.

AkThhhpppt• 14 years ago

There is the slight issue that no matter what energy source we use, we need to reduce energy growth. Postulating a meagre 2.3% growth in energy use forever, we'll get the surface temperature of Earth to the boiling point of water in 450 years.

Source http://physics.ucsd.edu/do-the-math/2011/07/galactic-scale-e...

Tichy• 14 years ago

What about pollution? In a way I feel very pessimistic, because I can't find a reason why humans wouldn't exploit every resource to the maximum. For example fish in the sea, wood in the rainforest (or just surface below the rainforest), air, oil...

I think humans will survive, but how much will we destroy before reaching equilibrium?

What other things look great, besides iPhones? The economy? The state of understanding between countries, with more and more of them acquiring nuclear weapons?

victork2• 14 years ago

Sorry to say that but we cannot trust the weather forecast in simulation for more than 5 days and we trust a forecast for mankind 30 years from now?

I know people like these kind of studies, perhaps it conveys the feeling that "after me there won't be anything" and that we are the last generation but it's simply to complex to model. People have been saying the same things for generation and so far, so good (with some exceptions of course).

I am not saying that it's not going to happen, just that you have to be very careful with prediction such as these, take them as "work of fiction". Also don't forget a possible bias. Apocalyptic vision have always fascinated populations and men around the world but how many have happened?

kragen6• 14 years ago

You can't tell whether it's going to rain five days from now very reliably, but you can predict within a degree the average monthly temperature in any city in the world, for any month of the year, five years from now. Of course there are unforeseeable events, but that doesn't mean everything is unforeseeable.

In this case, we've had 40 years to test this forecast, and it looks like they've done a pretty reasonable job forecasting the key variables they were forecasting, 40 years in the future. That seems like a good validation of their model, and we should expect it to do nearly as good a job for the next ten years at least, if not 20.

So I don't think they should be taken as a "work of fiction", even if they might be wrong. The model should be taken seriously, and we should attempt to improve it or propose better models, even if those models have more uncertainty in their predictions.

There's a big difference between predicting an apocalypse based on a psychotic episode and predicting an apocalypse based on a dynamical model of the key variables in a world system.

randallsquared• 14 years ago

So the extremely mild winter (in the continental US) that everyone's been saying was so shocking was actually forecast years ago? Or are you saying that this capability has only been developed in the last year or so?

astrodust• 14 years ago

Weather patterns are extremely complex and yet fall within a certain set of bounds. A swing of ten degrees is perceived as a dramatic change. This is because the numbers involved are relatively small.

Resources and populations have much wider swings and the forces that perturb them need time to have an effect. The numbers involved are millions of times larger than temperatures. There's also much higher inertia than the weather.

It's impossible to predict the precise number of births tomorrow, or the amount of coal extracted to the ton, but you can come up with a very accurate estimate for the course of a year or a decade with the right data.

We can't predict the weather five days out, but we can predict the climate ten years out.

luser001• 14 years ago

False analogy.

"weather forecasting" involves fine-resolution (in both space and time) predictions. This is known to be difficult to do reliably ("butterfly effect").

This is more akin to climate analysis: low-resolution in space (continent-scale instead of ZIP-scale) of and time (decades instead of 24 hours). Much more amenable to statistical modeling.

YMMV.

vannevar• 14 years ago

The point of the article is that this particular simulation did in fact accurately forecast mankind's future 30 years into the future, from 1970 to 2000. If you had made your argument against the model in 1970, you would have been wrong. The implication now is that since the model accurately predicted the last 30 years, we should also trust it to predict the next 30 years. You might still argue with the conclusions, but you need to be more specific in your criticisms than "these things can't be predicted", because according to the article, apparently they can be. At least for the last 30 years.

scottw• 14 years ago

"Population declines following economic collapse" should be "Population declines following sustained drop in birthrate." The population is going to decline regardless of what the future economy does.

kragen6• 14 years ago

I'm not very familiar with their model, but if the birthrate asymptotes to above the replacement rate, or goes back up, the population won't decline. So the economy might be a factor.

schiffern2• 14 years ago

scottw is referring to the well-studied demographic transition.

http://en.wikipedia.org/wiki/Demographic_transition

jonmc12• 14 years ago

Criticisms of World3 model: http://en.wikipedia.org/wiki/World3#Criticism_of_the_model

The new book, Abundance, has an informed point of view that speculates an opposite reality in future: http://www.abundancethebook.com/qa-2/

jbooth• 14 years ago

So, I'm as concerned about environmental and energy concerns as the next guy, but I noticed something about this graph..

The big predictions haven't happened yet. The part where we're tracking perfectly is just an almost-linear continuation from where we were before. You can make the case that that's unsustainable (and I'd be convinced), but that doesn't mean this model's predictions are borne out by data we've seen so far.

olalonde• 14 years ago

My thoughts exactly. Fixed the graph to reduce bias: http://dl.dropbox.com/u/3750008/Screenshots/r.png

Eyght• 14 years ago

I'm curious if the decline in industrial output per capita can be explained by the increase in population alone, or if it has decreased more than that.

wazoox• 14 years ago

For those interested on well documented complements to this, don't forget to check the "Do the math" blog: http://physics.ucsd.edu/do-the-math/

nfassler• 14 years ago

If you want a more nuanced discussion of the topic, check out the recent talk by Dennis Meadows, the originator of this chart. This is from an event by the Smithsonian commemorating his book, "Limits to Growth":

http://youtu.be/f2oyU0RusiA?t=5m45s

dclowd99012• 14 years ago

What I don't understand about these charts is they completely dismiss the impacts of diminishing returns.

Suppose the population continued to grow and grow and grow. What would happen to available non-renewable resources? They would become more and more expensive to a point that their cost would exceed the cost of finding alternate means of producing energy. What happens then? we stop relying on fossil fuels, and start relying on more sustainable energy sources, as a practical matter of the economics of it.

Food production isn't a non-renewable source, but it is a control. Only so many people can afford so much food; at a point it will be prohibitively expensive to procreate. If they can't children die, or families stop having children. Does that mean all population growth will backslide? No; why would it? It just means there becomes a harder cap on how many children a person or family can afford to have. No more 3+ children in families.

refurb• 14 years ago

Agreed. These predictions assume that behavior never changes. Just like when gas prices skyrocketed a few years back and you could buy a SUV for a fraction of the value a year ago.

Another great example is oil. When oil was cheap and plentiful, people screamed "we're running out!!". Prices went up and suddenly it was economically viable to frack and extract from tar sands. Boom, we have a bunch of "new" oil.

dclowd99012• 14 years ago

One takeaway I got from the oil uptick a few years back (~$150/barrel, if I recall), is that people will change their behavior. In 50 years, driving habits continued trending up and up, but in that time people actually drove less.

It doesn't take a genius to figure out what that means. They actually changed their lifestyles to accommodate the pinch they felt. Carpooled. Took fewer road trips. Consolidated trips. And it wasn't even an issue of shortage; it was purely speculative increases.

taliesinb• 14 years ago

I don't think that is true. As for as I recall, the World3 model includes price feedbacks like this.

But even if it didn't, one of the lessons of World3 is that it takes time for negative feedbacks like this to achieve equilibrium. If the feedback is slow enough, you get overshoots, and those overshoots either are (by definition) or could trigger (as a side effect) environmentally and socially damaging events. In the case of population, for example, the recovery after a large overshoot could take the form of mass famine or civil war.

There is another problem with the argument that many free market optimists make about energy: to actually scale up whatever fancy clean-energy technology happens to become economically viable in the future might require huge swathes of our economies to be reconfigured at an impractical rate.

To give an example, there are physical limits to how quickly you can ramp up the volume of solar panels, no matter how cheap the technology is, to do with quickly we can ramp up the production of pure silicon, build plants that make solar panels, and train engineers to oversee those plants and install those panels into the grid.

Of course, we can't quantify these limits for some mystery future technology, but we can play the game for known technologies, and it doesn't look good.

In particular, it seems that it is only really realistic to be off fossil fuels by 2050 if we start transitioning aggressively now using many different approaches --simultaneously. In other words, we need to place a lot of large bets, not just one large bet or several small ones -- see [1] for example.

Given the reluctance of the world's largest producers, consumers, and polluters to even get serious about one of these approaches, it seems pretty hopeless that we have the political will to execute on all of them, simultaneously, at global scale, as we need to.

As usual, the poor will suffer disproportionately.

[1] http://www.aaas.org/news/press_room/climate_change/mtg_20070...

Another Look at "The Limits to Growth"

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