petrol bad, hydrogen good - any chemists out there
petrol bad, hydrogen good - any chemists out there
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crossma

Original Poster:

12 posts

271 months

Wednesday 27th July 2005
quotequote all
noticing the great chuffs of water vapour from the back of one of those new fuelcell buses in London raised a question with me. We don't/didn't know the effects of all these millions of tons of CO2 emmissions on the atmosphere, but what impact would millions of tons of H20 being generated by fuel cells instead have if we switched over? Are all the environmentalists forcing us down a route that will be even worse in the future?
My basic understanding would be that more water vapour would eventually lead to more water, and more clouds would make global warming worse. More rains, floods, clouds, all of this is what we are trying to avoid isnt it?

Anyone out there actually know any science about this?

mybrainhurts

90,809 posts

284 months

Wednesday 27th July 2005
quotequote all
Don't worry....97% of greenhouse gas is water vapour...


hang on a minute........

scorp

8,783 posts

258 months

Wednesday 27th July 2005
quotequote all
I think you underestimate the total volume of water on earth, i doubt we would make hardly any difference to it.

xm5er

5,094 posts

277 months

Wednesday 27th July 2005
quotequote all
crossma said:
noticing the great chuffs of water vapour from the back of one of those new fuelcell buses in London raised a question with me. We don't/didn't know the effects of all these millions of tons of CO2 emmissions on the atmosphere, but what impact would millions of tons of H20 being generated by fuel cells instead have if we switched over? Are all the environmentalists forcing us down a route that will be even worse in the future?
My basic understanding would be that more water vapour would eventually lead to more water, and more clouds would make global warming worse. More rains, floods, clouds, all of this is what we are trying to avoid isnt it?

Anyone out there actually know any science about this?


And that's before you ask how much oil/gas/coal is burned to produce the electricity you need to crack the water to produce the hydrogen you need to transport to the bus to transport the proles who cant afford a car any more 'cos petrol is now £5/litre.

Tuna

19,930 posts

313 months

Wednesday 27th July 2005
quotequote all
Though there would be more water vapour generated, there wouldn't be any significant force increasing the 'stable' humidity of the atmosphere. Hence, rain (or dew overnight).

It might rain a little (very little) more.

Ecks Ridgehead

4,285 posts

257 months

Wednesday 27th July 2005
quotequote all
crossma said:
noticing the great chuffs of water vapour from the back of one of those new fuelcell buses in London raised a question with me. We don't/didn't know the effects of all these millions of tons of CO2 emmissions on the atmosphere, but what impact would millions of tons of H20 being generated by fuel cells instead have if we switched over? Are all the environmentalists forcing us down a route that will be even worse in the future?
My basic understanding would be that more water vapour would eventually lead to more water, and more clouds would make global warming worse. More rains, floods, clouds, all of this is what we are trying to avoid isnt it?

Anyone out there actually know any science about this?


The worry is not so much the emissions created by the fuel cell itself, but the energy required and the byproducts created (carbon monoxide, in steam reforming) by the manufacture of the hydrogen to go in the cell in the first place.

planetdave

9,922 posts

282 months

Wednesday 27th July 2005
quotequote all
The hydrogen used in fuel cells must surely be split from water...if it goes back to water then the net amount remains the same.

Cows are a menace - the amount of methane they produce is prodigeous and it's about 10* worse than CO2 for greenhouse properties.

And will someone put a plug on those volcanoes!

TeamD

5,060 posts

261 months

Wednesday 27th July 2005
quotequote all
I've been considering a related point recently...

Our fossil fuels that we burn thus converting the carbon within them into CO2 must have come from somewhere, that is, they were once trees and animals etc. So where was the Carbon before these lifeforms utilised it for their structure? In the atmosphere by any chance? If so, why should a return to prehistoric times and higher CO2 levels spell doom now and not then? Perhaps a naive and silly question, but I just wondered.

Einion Yrth

19,575 posts

273 months

Wednesday 27th July 2005
quotequote all
TeamD said:
I've been considering a related point recently...

Our fossil fuels that we burn thus converting the carbon within them into CO2 must have come from somewhere, that is, they were once trees and animals etc. So where was the Carbon before these lifeforms utilised it for their structure? In the atmosphere by any chance? If so, why should a return to prehistoric times and higher CO2 levels spell doom now and not then? Perhaps a naive and silly question, but I just wondered.


A good and pertinent question actually. Atmospheric CO2 levels have been vastly higher in earlier epochs, than they are now, the planet was warmer and wetter. Climate change is a fact, but there's buigger all we can do about it, so we are going to have to learn to adjust. (Oh and anthropogenic global warming is very far from being proven fact).

>> Edited by Einion Yrth on Wednesday 27th July 14:18

mybrainhurts

90,809 posts

284 months

Wednesday 27th July 2005
quotequote all
We're doomed........doomed, I say

TeamD

5,060 posts

261 months

Wednesday 27th July 2005
quotequote all
Ok, glad to know it's not a total dunce of a question...so following on...

If we are to believe the gloom and doom merchants who are all jumping on the Carbon Trust bandwagon, we have very little time to stop this catastrophic change in our environment, which they would have us believe is irreversible. So how did our wonderful planet sort itself out before? Come to think of it, in the long term, burning fossil fuels can be considered to be carbon neutral because it's only stuff that was there before, unless they've come up with a new way to manufacture elements that is.

crossma

Original Poster:

12 posts

271 months

Wednesday 27th July 2005
quotequote all
Thanks for the replies so far, I purposely didnt even mention the fossil fuels that are required to power the plants to make the hydrogen.

If you believe global warming is due to man's CO2 emmissions, then a similar amount of H20 could cause problems (extending their logic)

My understanding regarding prehistoric CO2 levels is that plants and animals were resistant to higher CO2 levels and evolved as the atmosphere slowly changed.

If the SavetheEarth brigade are to be believed the danger is that climate change is happeing too fast too evolve.

My question is why the environmentalists urging us in this direction?

TeamD

5,060 posts

261 months

Wednesday 27th July 2005
quotequote all
I think they've been trying to come up with something like this for decades. It's another excuse for hoards for council employees checking your carbon emissions and taxing you on it. In the abscence of any kind of industry producing stuff, they have to find a job for folk, what do they care if their efforts have all the effect of trying to drain the Atlantic with a teaspon. As long as you believe it's true, then what do you care? Environmentalism, the new religion.

theexcession

11,669 posts

279 months

Wednesday 27th July 2005
quotequote all
I seem to remember reading that to re-fix all the carbon that has been released by mankind into the atmoshpere would take about 10,000 years.

Given the rate at which the rainforests are being destroyed, the outlook for getting all this carbon back out of the atmoshphere and into plant material is pretty bleak.

Secondly, if we take a look at the major producers of carbon based atmospheric pollution - I believe currently the biggest worry is India, where the majority of cooking is performed using wood fires.

Any pilot who flies long haul over India will be able to confirm the pressence of a large yellow cloud covering the continent and stretching out over the India Ocean. The long term effects of this cloud are still somewhat cloudy so to speak, but people are concerned.

Finally of course there is the volcano impact, one major erruption dumps way more carbon (and other nasties) into the atmoshpere than our bumbling around in motor cars.

best
Ex

Sonic Nonsense

283 posts

254 months

Wednesday 27th July 2005
quotequote all
TeamD said:
I've been considering a related point recently...

Our fossil fuels that we burn thus converting the carbon within them into CO2 must have come from somewhere, that is, they were once trees and animals etc. So where was the Carbon before these lifeforms utilised it for their structure? In the atmosphere by any chance? If so, why should a return to prehistoric times and higher CO2 levels spell doom now and not then? Perhaps a naive and silly question, but I just wondered.


Plants convert CO2 to oxygen by breathing in carbon dioxide, absorbing the carbon into their structures and breathing out oxygen. They're pretty useful in that respect! Then when they die, they become oil, gas, or coal after approximately 1.2 bjillion years. (in the mean time they may be eated my animals which inherit the carbon that way, then they die, etc, etc).

If we start barrelling loads of water into the atmosphere, very little will happen, i believe. To create the hydrogen for the fuel cell in the first place, they 'crack' water, thus the overall water level will be maintained on it's recombined in the engine.

Admittedly, at the moment, generating the energy for these motors does require some kind of generator elsewhere (usually fossil fuel) so in fact, you're only moving the site of the pollution elsewhere. However, in the near future, nuclear fusion will become a realistic method of generating energy (the ITER (international thermonuclear expeimental reactor) will be built in France which will be the first fusion reactor to product more energy than it uses). This is an extremely clean form of energy production (compared to nuclear fission and fossil fuels), so ultimately fuel cells should cut pollution massively.

Tuna

19,930 posts

313 months

Wednesday 27th July 2005
quotequote all
crossma said:
Thanks for the replies so far, I purposely didnt even mention the fossil fuels that are required to power the plants to make the hydrogen.


Annoying fallacy. The plants that make hydrogen don't have to burn fossil fuels. They can be solar, hydro, nuclear, wind or a bunch of other technologies. Even if they are using fossil fuels they can be immensely more efficient than a typical car engine in converting their fuel to energy.

Converting to hydrogen allows CO2 emmissions to be removed from the process. Whether that helps anyone is another matter entirely.

TeamD

5,060 posts

261 months

Wednesday 27th July 2005
quotequote all
I agree with you in that volcanic events make our efforts look puny, but I seem to recall the scientists bleating about the cooling effect when Mt Saint Helens (I think) went pop, a la Nuclear Winter. It just seems that noone agrees on this subject, and that the vast majority of "warming" is due to the hot air being spouted by the various factions, reminds me of the bit in Hitchhikers guide where Deep Thought suggests to the philosphers that they would be on the gravy train for life if they got on the pundit circuit and violently disagreed with each other all the time. I'd also like to know how much CO2 is being released flying scientists and politicians around the world to various seminars and summits to discuss/speculate about the issue. If one were truly logical, then one would suggest that the only way to solve the problem would be to terminate all human life and leave the planet to it's own devices, but that would be just plain silly.

turbobloke

117,175 posts

289 months

Wednesday 27th July 2005
quotequote all
TeamD said:
If we are to believe the gloom and doom merchants who are all jumping on the Carbon Trust bandwagon, we have very little time to stop this catastrophic change in our environment, which they would have us believe is irreversible. So how did our wonderful planet sort itself out before?

According to those stomach churning Carbon Trust telly ads quoting Oppenheimer, we're all to blame and we can do something about it.
crossma said:
My understanding regarding prehistoric CO2 levels is that plants and animals were resistant to higher CO2 levels and evolved as the atmosphere slowly changed. If the SavetheEarth brigade are to be believed the danger is that climate change is happeing too fast too evolve.
Past carbon dioxide levels have been 18 times higher than now, but that's still not much. Currently atmospheric carbon dioxide stands at 0.038% by volume so the previous maximum was about 0.68% and yes there was no problem but not because of resistance or anything like that. Small levels of carbon dioxide in the atmosphere do nothing bad for animals, but a lot of good for trees and plants as carbon dioxide from the air helps make their food. There's no need for animals or plants to evolve resistance to carbon dioxide, but if temperatures go up and down as they do naturally then organisms will need to adapt to that.
theexcession said:
I seem to remember reading that to re-fix all the carbon that has been released by mankind into the atmoshpere would take about 10,000 years.
The pre-industrial level of atmospheric carbon dioxide was about 0.030%. As carbon dioxide levels change as a result of temperature shifts and not vice versa, and as the oceans are far more important than forests in terms of carbon dioxide and climate, a downward shift in temperature due to continuous natural climate change would lower the level in much, much less than 10000 years.

The order of events problem is just one of the many aspects of climate change unknown to your average green, as is the maximum warming that could be achieved by as much carbon dioxide as you like (it's about 0.8 degrees C). FWIW the atmosphere contains 750 GtC, while the surface ocean contains even more, 1000 GtC. Vegetation, soils, and general detritus contain 2200 GtC while the intermediate and deep oceans contain 38000 GtC.

Sonic Nonsense

283 posts

254 months

Wednesday 27th July 2005
quotequote all
turbobloke said:

The order of events problem is just one of the many aspects of climate change unknown to your average green, as is the maximum warming that could be achieved by as much carbon dioxide as you like (it's about 0.8 degrees C).


However, if you look at the graphs for the effect a tiny temperature change has, an increase in global temperature of around a degree can cause a runaway spike.

Don't get me wrong, i'm not a Greenpeace hippy, but I'm just aware of the emount of meltwater from the ice caps that it could take to effect the Gulf Stream, which is the only think keeping us from having the climate of Moscow.

turbobloke

117,175 posts

289 months

Wednesday 27th July 2005
quotequote all
TeamD said:
If one were truly logical, then one would suggest that the only way to solve the problem would be to terminate all human life and leave the planet to it's own devices, but that would be just plain silly.
Quite right because in spite of greens trying to get us to believe we're somehow outside of nature, humans are part of biosphere biodiversity and we're totally natural and organic
Sonic Nonsense said:
if you look at the graphs for the effect a tiny temperature change has, an increase in global temperature of around a degree can cause a runaway spike.
Is there a graph you could point us to? Not that long ago (holocene maximum) the global temperature was a several tenths of a degree higher than it is now, there was no thermal runaway.