Exponential Growth: The lillie pond riddle

[bitingmidge]

ideas of how to reduce ones consumption of the world resources.

Introducing really draconian workplace conditions and pay fixes excessive consumption!


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[Grunt]

Not exactly the Gaia stuff. Nature does have a way of dealing with plagues. If you remember the plague of mice in South Australia a few years back. There was suddenly a brazillion of the little frickers. Their environment couldn't support them, so they starved to death. For a period afterwards the mouse population was less than the average.

This is what happens to populations that are in overshoot.

Out of interest, 5 out of the last 6 years, the worlds grain production has not met demand. I've got to zing out but I'll find the link. It was from the US ag department I think.


Nuclear power is not the answer. To make a difference, we'd have to replace a significant percentage of the 10,000 coal based power stations. With growth in population, we'll need more power so the nuclear stations will add to rather than replace the coal based one.

Also, if we had 5000 nuclear stations we'd run out of uranium pretty quick. It's not that abundant. There is a huge amount of greenhouse gas producing energy required to build a nuclear jobbie.

[QldWoodie]

I'm not sure why I am replying to this thread because I never reply to threads like this, but something must have got me going so let me refer you to an economist from 200 years ago named Thomas Malthus who built a theory just like this one and amongst other things resulted in economics being called the dismal science but whose theories have been refuted by just about every bit of empirical evidence since then (excluding all the selective evidence of barrow-to-push zealots) so rest easy.

You'll note that the above is not a short sentence

Qw

[Grunt]

I think our friend Thomas will be proved right, at least in the sense that the population will outstrip our ability to grow food. He didn't grasp what the availablity of cheap oil would have on our food supply.

At our current rate of growth, the world's population will be close to 14 billion people by 2060. 53 years after that the population will be 28 billion. At what point are we unable to produce enough food to feed the population?

The world is finite. One day the well will run dry.

It's not only food, it's everything. Oil, copper, iron etc. It's not that we'll run out, it's just that to get the remainder of these things will be prohibitively expensive.

Also, modern farming practices are not sustainable. The main farming area in the U.S. is in the Mid-West. In 1940 the topsoil in this area was measured at an average of 12 feet. It is now measured in inches.

Wait until the price of oil reaches a point were we decide that we need to grow bio-fuels as a replacement oil. We'll be producing fuel not food. Someone is going to start starving. If the U.S. were to replace their current dependence on oil with bio-fuels they would have to harvest an area the size of Florida, everyday to meet demand.

I don't see a good outcome.

[Bodgy]

Groggs

Can you attribute and reference the source for your last paragraph re bio fuel?

Not saying its wrong but just seems incredible.

[Grunt]

Bodgy, I think you were talking to me.

Sorry, I've mis-quoted and my source made a mistake. It's every year not every day. This is to meet 10% of the U.S. needs. (Link to entire thread)

This is a post that I read a few weeks ago and it had changed a bit since then.

Ok Major screwup, thanks to Fletch for pointing it out. The math is off by a little bit (365 ). I don't try to mislead, I'm just bad at math. Basically, instead of Florida sized plot every day, it's year, which to me, is still a bad idea, for only 10% gasoline replacement.

I'm really getting tired of biofuel reports that don't show any numbers in terms of space required, so I've taken some considerable time to crunch some numbers for myself, and here's what I found:

320,000,000 gallons / day - U.S. gasoline consumption (roughly)
32,000,000 gallons is 10% of that / day
48,400,000 gallons is the equivalent energy in ethanol (only 2/3rds as powerful)

So let's see what it takes to produce that in ethanol. 10% of gasoline shouldn't be too hard.

6 tons of switchgrass / acre / year - normal Iowa switchgrass acre
70 gallons of ethanol / ton - current process efficiency
= 420 gallons of ethanol / year / acre
= 42,086,956.52 acres needed / year
= 65,760.86 square miles harvested & processed / year

Which means, to meet 10% of current gasoline energy demands, someone would need to harvest and process enough switchgrass equal to the entire state of Florida every year.

Ok so that's pretty messed up. But, wait, they say they are improving efficiencies like mad, while at the same time, using less nitrogen, etc. Great!

15 tons of switchgrass / acre / year - more than what they are hoping for
125 gallons of ethanol / ton - way more than they expect
= 1,875 gallons of ethanol / year / acre
= 9,438,383.84 acres needed / year
= 14,747,474.75 square miles harvested & processed each year

Which means, to meet 10% of current gasoline energy demands, using ridiculous figures that are way beyond even what optimists expect, someone would need to harvest and process enough switchgrass equal to the entire state of Maryland and Rhode Island every year.

Now this is just for switchgrass, I haven't analyzed other stuff. But from what I hear, switchgrass is the best, since sugar cane won't grow in the U.S. like it does in Brazil.

And notice that this doesn't talk in any way about all the nitrogren, potash, water, transportation, processing, and other energy costs, just the size of land needed.

People just do not understand how much oil we use per day and how powerful it is.

references:

http://www.hort.purdue.edu/newcrop/n...df/fuentes.pdf
http://www.grassland.unl.edu/Fall99.htm
http://www.harvestcleanenergy.org/en...ic_Ethanol.htm
http://www.extension.iastate.edu/Pub...ons/PM1866.pdf
http://www.onlineconversion.com/area.htm
http://en.wikipedia.org/wiki/List_of...states_by_area

[Groggy]

Groggs

Can you attribute and reference the source for your last paragraph re bio fuel?

Not saying its wrong but just seems incredible.

Moi? I think Grunt said that - bluddy dog is always misquoting

[echnidna]

Hey Grunt,

When yer go bush and live environmentally friendlier you dont need to grow oil plants to run yer engines on.

Flog yer car and get a horse and buggy. No more petrol needed and the exhaust emissions are very usable in the garden where ya grow yer grub.


and when the horse dies yer got a lot of hamburgers

[ozwinner]

Hey Grunt,

When yer go bush and live environmentally friendlier you dont need to grow oil plants to run yer engines on.

Flog yer car and get a horse and buggy. No more petrol needed and the exhaust emissions are very usable in the garden where ya grow yer grub.

I saw something years ago about just that.
If we all had horses instead of cars, the methane emited would far out way the carbon from the cars in the pollution aspect.

Pferrttttt

Al

[Grunt]

I could shove a pipe up the horse bum and collect the methane and burn that to generate electricity.

[Bodgy]

Thank you Grunt and apologies Groggs.

I think we are looking at the wrong end of all this. Finding new energy sources is the easy option, compared with changing peoples behaviour.

The US is the most profligate waster of energy, having spent much time there I find it obscene - the 6 litre inefficient SUVs, the air con and so on. Unfortunately, in a democracy, you can't give the people what they need, only waht they want. This problem will eventually be fixed by market economics. When fuel hits $5 a litre people will reconsider the Hummer.

Secondly the population explosion needs to be reversed, but, again, how are democracies going to do this? We keep people alive well past the veggie stage (at great economic cost to the community), large parts of the thrid world listen to the Catholic Church who simply want to grow their constituency, China had a go at limiting population growth and copped global condemnation. Again economics will probably solve this issue, however the 'aid' community will skew the result.

Go Gaia!!!!

[bitingmidge]

While there are still whales to eat, and koalas to skin, there's hope.


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