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Author Topic: wildfire and global warming  (Read 7047 times)

Offline Atomic-S

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wildfire and global warming
« on: 14/04/2007 05:13:28 »
I wonder how much CO2 is put into the atmosphere by wildfires. I wonder how that compares to human-caused sources (exclusive of human-ignited wildfires). I wonder if it would make policy sense to include, as a means against global warming, substantially increased funding for wildfire suppression? I wonder what the economics of underbrush-to-fuel conversion looks like?


 

another_someone

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wildfire and global warming
« Reply #1 on: 14/04/2007 05:55:47 »
I wonder how much CO2 is put into the atmosphere by wildfires. I wonder how that compares to human-caused sources (exclusive of human-ignited wildfires). I wonder if it would make policy sense to include, as a means against global warming, substantially increased funding for wildfire suppression? I wonder what the economics of underbrush-to-fuel conversion looks like?

Wildfire suppression is itself somewhat controversial.

In many forests, wildfires form part of the natural ecology of the forest; and prohibiting the wildfires can undermine the ecology of the forest.  The seeds of some trees are actually unable to germinate except after a wildfire.
 

Offline Biology Guy

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wildfire and global warming
« Reply #2 on: 14/04/2007 10:12:03 »

In many forests, wildfires form part of the natural ecology of the forest; a



Not if they are started by people though!
 

another_someone

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wildfire and global warming
« Reply #3 on: 14/04/2007 13:26:53 »

In many forests, wildfires form part of the natural ecology of the forest; a

Not if they are started by people though!

Firstly, the original question explicitly excluded fires started by humans, so I did not feel the need to address that issue.

Secondly, in some cases, fires started by people are merely doing what nature would anyway have done (i.e. the forest was ready to burn, and it just happened to be humans that created the spark).
 

Offline Seany

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wildfire and global warming
« Reply #4 on: 14/04/2007 14:19:50 »
I've heard somewhere that these yellow plants, where you find them alot in the U.K, a field covered all of yellow. Apparently these give off CO2, and not the other way, and this is a huge amount of Co2 given off. Anyone else heard of this?
 

another_someone

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wildfire and global warming
« Reply #5 on: 14/04/2007 14:44:24 »
I've heard somewhere that these yellow plants, where you find them alot in the U.K, a field covered all of yellow. Apparently these give off CO2, and not the other way, and this is a huge amount of Co2 given off. Anyone else heard of this?

I assume you are referring to rapeseed (not buttercups :)).

I am not aware of how they can of themselves contribute to CO2, although it is possible that the way they are subsequently processed might contribute to CO2 production.

As far as I am aware, all plants (there may be some exotic exceptions, but I am not aware of it) will obtain the bulk (and probably all) of their carbon that they need for growing from CO2 in the atmosphere.  Thus, so long as the plant is growing, then it is absorbing CO2.

The problems occur in two ways.

Firstly, after the plant stops growing.  If it dies in nature, then the carbon contained within it will be returned to the environment in one way or another, and this often incluses a substantial amount being returned as CO2 or methane (which is also regarded as a greenhouse gas, even more potent than CO2).  If it is harvested by man, then the question arises as to what man does with the harvested material.

The second issue is that if the plant is cultivated by man, then how much CO2 is produced in the farming process (in driving the tractors, in the production and application of pesticides, etc.).
 

Offline Seany

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wildfire and global warming
« Reply #6 on: 14/04/2007 17:52:56 »
Well, do we do anything with this rapeseed? Do we make oils out of it? Or it's just there, because it is excellent at reproducing..?

Also, isn't methane a gas that comes from our farts? ;D So, if everyone in China farts at the same time, our Earth will be full of green house gases! :o. Yes, no offence to the Chinese.

Also, if everyone in China smokes at the same time, there will be a massive fog.

Also, if everyone in China wees at the same time, there will be a flood!

Am I correct in saying that, if all the population of China comes to the UK? ;D
 

Offline Bored chemist

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wildfire and global warming
« Reply #7 on: 14/04/2007 19:24:17 »
Rapeseed oil is a commercial crop. It is harvested for the oil in its seeds. The direct production of methane in human guts is a small effect compared to the methane produced by farm animals. I read once that this, in turn is much less than that produced by termites.

There are something like 1.3 billion people in China. If they all came to Englang and relieved themseles then that would be something like 0.65 billion pints of pee. Converting that to metric gives 370000 cubic metres.

The area of the UK is about 243,000 square kilometres or 243,000,000,000 square metres.
Dividing one by the other gives us the average thickness of the layer of wee. It turns out to be a bit over a milionth of a metre deep; not much of a flood. Even if they all went to London and took a leak there (and I know some who say that's the best thing to do with London) it would still be less than a milimetre.
On the other hand that's enough piddle to fill a couple of hundred or so swimming pools so it's not something to be sniffed at.
If they all flushed afterwards that would (with a typical flush taking 2 gallons) be about 16 times as much water. Not enough to flood the UK, but it would certainly cause problems for the capital.
 

another_someone

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wildfire and global warming
« Reply #8 on: 14/04/2007 19:48:24 »
Rapeseed (or oilseed rape) is used for animal fodder, for cooking oil, and is now being used as a source for biofuels; and yes, it is grown because it is so easy to grow.

Methane is the gas that is commonly produced from the bacterial breakdown of much vegetable matter, and this will happen as much in the human intestines (and even more so in cattle and sheep) as it will elsewhere.  It is the methane produced by bacteria in the gut as it breakdown vegetable matter that causes the methane in farts.  The more roughage you eat, the more methane you are likely to eat.  If you eat a diet high in meat and low in vegetable matter, you will create less methane.

Methane is also what we regard as natural gas (the stuff we use for cooking and heating), and also what is sometimes used to power vehicles in the form of CNG (Compressed Natural Gas).
 

Offline Atomic-S

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wildfire and global warming
« Reply #9 on: 16/04/2007 07:32:46 »
Do we have any data on carbon dioxide production from wildfires?
 

another_someone

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wildfire and global warming
« Reply #10 on: 16/04/2007 08:28:08 »
Do we have any data on carbon dioxide production from wildfires?

I don't know of any, but the real question is over what time period are you measuring the CO2 production over.

There is also a difference in impact between forest fires and peat fires.

The problem is that in nature, the carbon in most wood will be naturally be recycled back into the atmosphere one way or another.  In these cases, all that the forest fire will do is accelerate that which would anyway happen.

It is a fallacy to regard forests as long term carbon sinks.

When we are talking about peat bogs, these can be long term sinks, and therefore their burning is returning carbon into the atmosphere where it might otherwise be locked up in the peat for a considerably longer time (I don't know how long, but it would not suprise me if it could stay there for millions of years).
 

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wildfire and global warming
« Reply #10 on: 16/04/2007 08:28:08 »

 

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