h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

hi folks, i'd appreciate any comments on this;

making coal


thinking about organic carbon storage possibilities, i realised the obvious thing would be to start making new coal.
fossil fuels formed from compressed plant matter prevented from oxidising by anaerobic conditions underwater, in swampland, peat bogs etc.
so we should be permanently re-flooding drained wetlands and re-planting mangrove and other costal forest.
as sea level rises, more potential sites would become available.
also, the costal plantings would provide storm protection, and upland peat bogs would act as a water store, decreasing the incidence of flooding downstream.
wetlands can be extremely rich and productive ecosystems, so the flooded areas would be an asset not a loss for humans and wildlife alike.
win-win situation?

cheers

With a payoff in a few million years?

We can even make it more directly, over a couple of years, it's just horrifically expensive. The reason we're being asked to go green is that it is the easiest and cheapest option.

Well we make charcoal, if that helps: you burn wood slowly but hot in a sort of kiln thing, where it has no oxygen.

Flooding forests to create future coal, after millions of years, is of course horrible inefficient. Its much easier to adapt to cutting out the middle parts of the procss and moving to burning the vegetation for power, which is carbon neutral if you manage the forests properly as you do it. (Europe at least has been very good at managing deforestation for all purposes in the last few decades.)

Whether that's more efficient than solar and tidal power sources I couldn't say.

sorry, maybe i should have thought of a different title!

i was not thinking of providing fuel, but of long-term carbon sequestration.
in a bog, the carbon would be locked in from the moment the tree/moss etc became submerged.

at the moment there are a lot of 'offset' schemes involving growing wood, but this is only short-term storage. either the wood will be;
burned,
turned into furniture or paper, the majority of which will get burned within a few decades,
or decay in situ. in this case, some of the carbon will enter the food chain, some will oxidise during decomposition and some will create soil. the soil will be a good sink in itself, releasing carbon over centuries, but this may be reduced to only decades if climate warming speeds up the oxidation process.

charcoal is a very stable form of carbon, the 'tera negra' of south america was created many hundreds of years ago by 'slash and char' farming, and is still black (hence name). main problem there is using the heat and volatile hydrocarbons given off in the charring process, this is done very efficiently in gasification plants in sweden. the temptation to burn such a high grade fuel is too great though.

people would also be bound to knick the bog carbon back as peat, this would not be as bad as burning fossilfuel since on shortterm carbon cycle, but would indeed rather defeat the object. mind you it takes a good few decades for peat to form, which would help spread the carbon emission 'spike' out a bit...

"in a bog, the carbon would be locked in from the moment the tree/moss etc became submerged."


This isn't actually the case. Studies of resevoirs used for hydroelectric power have shown that the amount of carbon/greenhouse gases coming off the water is equivalent to that of a coal power plant.

Surely it would vary significantly depending on just what was flood to create the resevoir, climate, depth, altitude and what was flowing into it?

Bogs store carbon until they dry out then they release it. I would imagine properly managed coppiced woodland is good short to medium term way of getting carbon out of the atmosphere is potentially economically, materially useful way.

"Bogs store carbon until they dry out then they release it."

Decay of vegetable matter is known to produce common greenhouse gases (CH4, CO2). These gases can easily travel through water - either by dissolving and then evaporating, or just simply as bubbles. It seems highly unlikely that Bog's only release carbon once they dry out.

Traveller in Time with the solution
"We should store the carbon in the only inert way it has, make more diamonds. There will be no urge to use it as fuel, no chance of it becoming airborn and lots of shiny stones.

Some oil companies pump back CO2 into oil fields, both to prevent the cavity from collapsing and to restore the balance a bit. "

Well they store a great deal more when wet and healthy than they do when they're drying out or being burned as fuel or being used as compost on flower beds.

"Well they store a great deal more when wet and healthy than they do when they're drying out "

You've stated this categorically several times, without providing any supporting information or arguments. Could you please elaborate as to why this is true? I would claim that the decay which causes the formation of green house gases only occurs (or is greatly accelerated) by being under water, and that the opposite is true.

"or being burned as fuel"

Well yes - I would have thought it was ridiculously obvious that burning something as fuel will release more gas into the atmosphere than *not* burning it.

>> Could you please elaborate as to why this is true? <<

Come on, Arnie

Initial condition : barren land with no appreciable organic carbon content

Final condition : swamp underlain by tens of metres of carbon rich deposits

For this to happen active wetlands have to be net consumers of carbon whatever carbon may also be given off during the decay processes.

The problem with promoting wetlands as carbon reservoirs as a global strategy is that it's fairly short-term and small-scale.

Now, if you could increase the rate of carbonate deposition in the abyssal plain ......

I simply chimed in with support of preserving the peat bogs we have, they may give off methane but they do store a hell of alot of CO2.

Seth - I had no idea that the initial condition was "barren land". So basically you flood an area of barren land to make a swamp?

Azathoth - yes, you've said it many times. And I've said many times, why?

thanks folks great stuff.
seems main problem is methane emissions.
in a balanced established shallow marsh ecosystem, a lot of the methane produced is taken up by methane eating bacteria (methanotrophs), and enters the food chain. some marsh gas will escape, i will have to find out how much.i suspect it will be from deeper pools in the marsh.
suddenly flooding an area will be bad, as with reservoirs, as the vegitation just dies and the methanotrophs are not there to take it up, and it is too deep. slowly returning a drained marsh to its original state would probably be fine. the woodland trust are doing this to one of the mosses near manchester, thats what got me thinking about this.
also there are going to be coastal areas which we will have to give back to the sea (current euphemism is 'managed retreat') so it would mke sense to try and use them, hopefully a marshland strip would build up as fast as it sank, making a barrier.
as for putting carbon back into the sea, this happens in mangrove swamps, when there is a storm, loads of sediment rich in stable carbon gets washed out and onto the seabed.
love the diamond idea, now we need an energy free way to make them

preview is my friend

Excellent point about the lack of methanotrophs in a suddenly flooded resevoir. Thank you.

"Azathoth - yes, you've said it many times. And I've said many times, why?"

And I ignored you because your behaviour on site of late and tone leaves me with impression that you weren't asking why in practice peat bogs store CO2 but that you were merely barracking.

Well this is the "Science Explained" Forum - but excuse me for asking for explanation. And who are you - the Hootoo Police?

Well right on cue: the front page of this morning's Independent.

http://news.independent.co.uk/environment/climate_change/article2539349.ece

Traveller in Time sorting threads
"Even better link < F2124165?thread=3833953 >




Why not bury plants ? "