Something nearly everyone's overlooked.

Doly · Expert Joined: Dec 03, 2004 Posts: 4040

There are two problems with this scenario:

1) Assuming that PO will cause less CO2. Many believe that everybody is going to turn to coal, and keep producing too much CO2.

2) Assuming that reducing gradually CO2 would cause an ice age. Pre-industrial levels of CO2 are most likely to cause pre-industrial climate. True, there is the issue of global dimming (pollutants that reflect sunlight). But I wouldn't expect any climate change to happen all of a sudden. There will be time to prepare, and even (hopefully), to find a solution.

Licho · Posted: Thu Mar 31, 2005 4:52 am Post subject:

If we stop industrial production, pollutants that decrease visibility will fall down to earth much faster, than we can get rid of CO2...

sjn · Posted: Thu Mar 31, 2005 6:52 am Post subject:

marko · Posted: Thu Mar 31, 2005 10:36 am Post subject:

Two hypotheses are under discusion here: 1) a sudden end to particle emission stops global dimming while warming persists, leading to a positive feedback loop of overheating; and 2) a sudden end to CO2 emissions causes phytoplankton and other flora to quickly suck CO2 out of the atmosphere, leading to a severe ice age.

Both hypotheses involve an assumption that the end of particle or CO2 emission will be sudden, whereas it almost certainly will not. Both will end gradually.

While it is true that the effects of CO2 warming last longer than those of particles in the atmosphere (which precipitate more quickly), over the rest of this century, the proportion of particles to CO2 emissions will rise, offsetting the lasting effect of earlier CO2 emissions. This is because we will shift from burning petroleum, with relatively little particle emission, to burning coal, and increasingly, wood, both of which produce much more ash and soot per unit of CO2. This will keep the dimming process going, probably enough to keep the arctic methane frozen as CO2 levels start to drop.

It may well be that the decline in CO2 levels are accelerated by uptake in the oceans and on land by plants and microbes accustomed to higher levels. However, people will still be burning wood. Also, as these organisms die, the carbon that they have sequestered will mostly return to the atmosphere as CO2 through decomposition. So the drop in CO2 is unlikely to go into a positive feedback loop either.

pea-jay · Posted: Thu Mar 31, 2005 3:48 pm Post subject:

I have posted time and time again that I cannot buy the arguement that coal will step into fill the oil gap. Modern coal mining is only possible by huge expenditures of petroleum to power the equipment. The easy EROEI coal has long been consumed. Gone are the days of pick-axe or even longwall mining. Today's coal in Appalachia comes from mountain-top removal. If you have to remove an entire mountain to get access to a seam, you are investing an incredible amount of energy.

What's the real EROEI here?

To expect that this process will pick up the slack ignores the fact that many of these producers are near capacity and that any increases would require additional expenditures of oil to accomplish. Even if oil (diesel) was directed towards this usage, the coal prices would rise to reflect the increased cost and as a result may price coal's usage out of range of some potential users reach.

The demand will go up for coal I agree, I just do not think that will translate into more supply. I have not been convinced.

And if the true EROEI for coal dips below 1 you can pretty much forget about its usage for energy purposes.
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nth · Light Sweet Crude Joined: Feb 24, 2005 Posts: 1976

what evidence does this author have that CO2 increase caused more plants and algae to grow?

in labs, this scenario is true, but no survey over any fields have identify increase plant foliage or algae due to elevated CO2. On the contrary, for all the plant studies I have read all point to nutrient and water as the limiting factors to plant growth. It was never about CO2.

marko · Posted: Thu Apr 07, 2005 8:04 pm Post subject:

Good points from both nth and pea-jay. Based on nth's point and my point about decay, I think that we can rule out the ice-age scenario.

Pea-jay's point adds weight to the "greenhouse effect run amok" scenario.

Still, I am not sure. Why is petroleum necessary for coal mining? I understand that lots of energy is necessary, but why can't miners shift from petroleum-powered to coal-powered (or steam-powered) machinery? I imagine that such machinery either doesn't now exist or isn't produced in significant amounts, but if petroleum prices keep rising, it will be produced. It just seems inevitable to me that coal production and consumption, and consequently the release of soot and ash, will increase.

Also, while open pit mining may be the cheapest and most profitable way to mine coal now, when energy is cheap, it may not be the most energy-efficient way. I am obviously no expert on mining, but perhaps there are less energy-intensive ways of extracting the coal. Instead of removing the mountain, maybe you build tunnels into it, as they did in the old days.

nth · Light Sweet Crude Joined: Feb 24, 2005 Posts: 1976

marko,

i agree with you that increase oil prices will force the industry to change its practices and go back to labor intensive coal mining instead of machine intensive. as long as the transition is gradual, people will be able to apply technology to save on energy to harnest coal.

the idea that coal costs more now to mine than old days- i agree it does cost more, but it is same for NG, Oil, and other fossil fuels. as you deplete the resource, you need to spend more energy to find more and the ones you do find are going to be smaller and maybe deeper or harder to reach- not develop regions. i think the key thing here is that all major coal areas are developed already. any new areas will be smaller in amount, so not as profitable, especially with infrastructure costs rising.

BlisteredWhippet · Intermediate Crude Joined: Feb 08, 2005 Posts: 863

bobcousins · Posted: Sat May 14, 2005 6:31 pm Post subject:

Actually, this is not a crackpot idea. The ice age is very real. The amount of CO2 varies roughly with 3 orbital oscillations. I think the analysis is a bit off though, as the planet becomes frozen less biotic activity occurs and so less CO2 is generated, probably it is also scrubbed out of the atmosphere (weathering etc).

There was an article about this recently in Scientific American, the full paper is here http://courses.eas.ualberta.ca/eas457/Ruddiman2003.pdf. Look at the graph on p.263.

After peak oil we will hit a glacial period, in a few thousand years. I don't think peak oil will wipe out civilisation, but a glacial period certainly will.
In fact what we need to do is burn as much fossil fuel as we can, changing the orbit of the planet is not an option.
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TrueKaiser · Intermediate Crude Joined: Oct 28, 2004 Posts: 539

*sigh* and you think thats going to happen like he described?
it's just another alarmist chicken little site, just this one covers peak oil, which is not the end of the world.
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J · Coal Joined: May 16, 2005 Posts: 1

I think if you consider the Earths ability to buffer and rebound from catastrophe, you might not worry so much. We were struck by the dinosaur killer Chixlub and yet the planet maintains life quite well. A supervolcano eruption will tip the climate on its ear, but it resolves itself. The gradual buildup of CO2 will have an effect on climate, but it seems we have weathered much worse here on the planet.

Now, mind you, man only just survived the eruption of the Toba supervolcano, but with population as great as it is today, survival should be something reasonable to expect, even if there is climate change. Technology will help, but it is knowledge that should enhance our ability to survive as a species.

I rather think that human population growth brought on by cheap energy, which is the crux of the rest of these issues, is what the Earth is about to try and correct soon.