4 ms·

In a pond, water lilies multiply each day so as to double in size. It takes 30 days to occupy half the pond. How much time is left until the pond is full? --

In a pond, water lilies multiply each day so as to double in size. It takes 30 days to occupy half the pond. How much time is left until the pond is full? ---- In other words: when we'll reach the limits, we won't have a lot of time to react.

pphysch 4y ago
We don't have a steady 100%/day population growth rate, we have a 1%/year and falling growth rate. Your analogy is off by several orders of magnitude, which leads to qualitative differences.
time_to_smile 4y ago
This isn't a great example because most species will experience sigmoidal growth, not exponential growth, and consequently not suffer catastrophic collapse. As they put pressure on the carrying capacity of their environment, the environment pushes back effectively and puts pressure on the populations. In most systems some sort of stasis is reached (or you get some kind of cyclical population trend). The trouble with humans is, because of ready access to fossil fuels and non-renewable energy, we have been able to artificially (or maybe more accurately phrased "unsustainably") extend beyond the carrying capacity of our ecosystem. Indigenous populations of the Americas had populations in the millions but never risked, at least in North America, systemic collapse because they largely lived sustainably. Ironically it's precisely because Malthus was proven wrong that we are in trouble. We have way, way higher energy demands than can be reasonably sustained without relying on a non-renewable source of energy. This completely disregards the additional problem of climate change. This sets us up for a type of collapse that is not usually a problem for most species, such as your lily pads.
- nverno 4y ago
  If you consider nuclear a renewable source, we could easily cover our current costs with it.
  - dane-pgp 4y ago
    Yes, with nuclear energy, we'll be able to provide for humanity's needs until the global population is back down below 7 billion, which, if things go well, could be reached about 100 years from now, and, if things go badly, could be reached about 100 minutes from now.
- munk-a 4y ago
  Yup, and the crappy news for humanity is that if we're expending unsustainable resources to artificially boost our population capacity that factor is likely to "correct" with a die off. In our modern world you'd like to think that as rational beings we'd be conserving these unsustainable resources to fund "important" things - but no, we usually just release strategic oil reserves to try and game our political system... and we decrease the resource intake to reap short term gains.

pphysch 4y ago

We don't have a steady 100%/day population growth rate, we have a 1%/year and falling growth rate. Your analogy is off by several orders of magnitude, which leads to qualitative differences.

time_to_smile 4y ago

This isn't a great example because most species will experience sigmoidal growth, not exponential growth, and consequently not suffer catastrophic collapse. As they put pressure on the carrying capacity of their environment, the environment pushes back effectively and puts pressure on the populations. In most systems some sort of stasis is reached (or you get some kind of cyclical population trend). The trouble with humans is, because of ready access to fossil fuels and non-renewable energy, we have been able to artificially (or maybe more accurately phrased "unsustainably") extend beyond the carrying capacity of our ecosystem. Indigenous populations of the Americas had populations in the millions but never risked, at least in North America, systemic collapse because they largely lived sustainably. Ironically it's precisely because Malthus was proven wrong that we are in trouble. We have way, way higher energy demands than can be reasonably sustained without relying on a non-renewable source of energy. This completely disregards the additional problem of climate change. This sets us up for a type of collapse that is not usually a problem for most species, such as your lily pads.

nverno 4y ago
If you consider nuclear a renewable source, we could easily cover our current costs with it.
- dane-pgp 4y ago
  Yes, with nuclear energy, we'll be able to provide for humanity's needs until the global population is back down below 7 billion, which, if things go well, could be reached about 100 years from now, and, if things go badly, could be reached about 100 minutes from now.
munk-a 4y ago
Yup, and the crappy news for humanity is that if we're expending unsustainable resources to artificially boost our population capacity that factor is likely to "correct" with a die off. In our modern world you'd like to think that as rational beings we'd be conserving these unsustainable resources to fund "important" things - but no, we usually just release strategic oil reserves to try and game our political system... and we decrease the resource intake to reap short term gains.