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Offline inbalance

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Methane emissions - how bad are they?
« on: 20/07/2007 18:03:27 »
Hi all

I've got a question on methane that I thought someone might be able to shed some light on…

I’ve been looking at some documents. ‘Hot Climate, Cool Commerce’, published the GHG protocol (a World Resources Institue project) says that 14% of greenhouse gas emissions are methane, while 77% are CO2.

A Defra document of conversion factors shows that the warming effect of methane is 21 times that of CO2.

These data suggest that methane emissions are a problem approximately four times greater than CO2. This sounded strange to me given that attention seems to be focused on CO2.

Does anyone know if I’m right in my interpretation of these numbers?

Thank you!


 

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Methane emissions - how bad are they?
« Reply #1 on: 20/07/2007 18:21:38 »
That'd be a question for Another_Someone. Welcome here!
 

paul.fr

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Methane emissions - how bad are they?
« Reply #2 on: 20/07/2007 18:46:32 »
Methane is released during coal-mining activities, oil exploration and when vegetation is burnt during land clearance. The main source of methane though is agricultural activity. It is released from wetlands such as rice paddies and from animals, particularly cud-chewing species like cows. The problem with methane is that as the world population increases, agricultural activity must increase and so emissions of methane will also increase. Since the 1960s the amount of methane in the air has increased by 1% per year - twice as fast as the build up of CO2 .

Then you also have Methane gas that bubbles up from Siberian lakes at up to six times the rate previously thought Some of the methane diffuses through the lake water and into the air, but the majority of it escapes by bubbling to the surface. Until now the  process has been hard to measure because of the difficulty involved in determining where and when the bubbles will occur.
studies have been made, ehere they used a combination of aerial surveys, remote sensors and year-round measurements of places in two Siberian lakes where methane bubbling was known to occur. To identify bubble hot spots, they surveyed the lakes in autumn, when bubbles rising to the surface freeze in place, leaving behind visible trails.

Extrapolating their data to Siberia's other lakes, the researchers estimate that more than 4 million tons of methane is being released each year.

I believe that in a previous topic i suggested that, the buring of Methane (as a fuel), from places such as landfills would not only give us a (sort of) free energy source. But also, negate some of the effects on global warming caused by Methane in the atmosphere.
 

another_someone

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Methane emissions - how bad are they?
« Reply #3 on: 20/07/2007 19:30:33 »
According to:

http://www.epa.gov/methane/sources.html

The top three producers of methane in the USA are, in order, landfills, natural gas (which is methane, and any leaks are just pushing methane straight into the atmosphere), and livestock farming.

It claims that 60% of global methane is anthropogenic, although by its own admission, we still don't know that much about all the possible natural sources of methane (including that generated by the Amazon forests).

One other factor with methane is that it is relatively short lived in the atmosphere (I don't know how long it lasts, but it will eventually burn to form CO2 and water).

According to Wikipedia:

http://en.wikipedia.org/wiki/Methane
Quote
Methane is a relatively potent greenhouse gas with a high global warming potential (i.e., warming effect compared to carbon dioxide).[1] When averaged over 100 years each kg of CH4 warms the Earth 25[2] times as much as the same mass of CO2. The total warming effect of CH4 is smaller than that of CO2, since there is approximately 220 times as much CO2 in the Earth's atmosphere as methane.

On the other hand, what this ignores, if the EPA report is to be believed, that the majority of methane in the atmosphere is anthropogenic, while only a small fraction of the CO2 is anthropogenic; thus if human activity is making a difference to the climate, that difference should be more significant in its methane production than its CO2 production.

http://en.wikipedia.org/wiki/Global_warming
Quote
On Earth, the major natural greenhouse gases are water vapor, which causes about 36–70% of the greenhouse effect (not including clouds); carbon dioxide (CO2), which causes 9–26%; methane (CH4), which causes 4–9%; and ozone, which causes 3–7%
« Last Edit: 20/07/2007 19:41:49 by another_someone »
 

paul.fr

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Methane emissions - how bad are they?
« Reply #4 on: 20/07/2007 21:12:07 »
This sounded strange to me given that attention seems to be focused on CO2.

Thank you!

According to:

http://www.epa.gov/methane/sources.html

The top three producers of methane in the USA are, in order, landfills, natural gas (which is methane, and any leaks are just pushing methane straight into the atmosphere), and livestock farming.

Assuming wikipedia is correct, and going back to part of the original question. Why do we hear so much about C02, and what we should be doing to combat those emissions?

One possible answer is that as an individual there is little you can do about the methane emissions, afterall you have no control over landfill, methane leakage and livestock. But, you can control or reduce your own C02 output.
 

another_someone

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Methane emissions - how bad are they?
« Reply #5 on: 20/07/2007 21:53:32 »
Assuming wikipedia is correct, and going back to part of the original question. Why do we hear so much about C02, and what we should be doing to combat those emissions?

One possible answer is that as an individual there is little you can do about the methane emissions, afterall you have no control over landfill, methane leakage and livestock. But, you can control or reduce your own C02 output.

I don't see that as actually being the case.

What is true is that we would have great difficulty controlling the number one greenhouse gas, namely water vapour.

There are difficulties in controlling both CO2 and CH4; but landfills can be controlled (either by not having them, which is what our government is trying to achieve), or by siphoning off the methane, or by aerating them so that the anaerobic bacteria that generate the methane cannot survive.

Clearly, reducing emissions of natural gas is in everybody's interest, but given the enormous amounts of it being piped around, how do you guarantee the minimum of leakage?

Reducing methane production from farm animals has also been suggested by changes in their diet (although one has to ask whether too close a concentration on rapidly introducing new diets to reduce methane might put the health of the animals at risk - i.e. we need time to asses the full range of health impacts of the new diets).

By comparison with the very wide range of situations in which we generate CO2 (possible half of human activity in one way or another), controlling CH4 production would seem considerably simpler than controlling CO2.

I suspect the reason why we concentrate more on CO2 production than CH4 production is more political than technical.  It has taken us about 20 years of political campaigning to develop the political inertia we have today with regard to CO2, and not only have we not had the time to develop that inertia for CH4 suppression, but many might consider that changing focus from CO2 to CH4 might risk losing political inertia for CO2 while not yet having attained a comparable inertia for CH4.

Politics needs to simplify things, with clear good guys, and clear bad guys - and having a clearly and unambiguously defined bad guy in CO2 is as much as the politicians can cope with.
 

paul.fr

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Methane emissions - how bad are they?
« Reply #6 on: 20/07/2007 22:03:26 »
Granted, the less we put into landfill the less methane is produced. I would however, suggest that our government are not out of the goodness of their hearts or their concerns for the enviroment trying to lessen our landfill use.

I would sugest that this is because brussels has told them to do so with fines attached for not reducing landfill, and to look good to the voters.

Ofcourse, the government has a lot invested in telling us about C02 emmissions, both time and money. To suddenly tell us that well, Methane is actually more of a concern would lead to the general public questioning climate change and the policis of the government.

I believe they just give us enought information to both inform and scare us in to taking individual measures
 

Offline inbalance

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Methane emissions - how bad are they?
« Reply #7 on: 20/07/2007 22:24:25 »
Hi guys - thank you for all the information. So the methane in the atmosphere has a smaller warming effect than CO2, because there is considerably less of it. But it sounds like the warming effect of methane emissions is greater that that of CO2 emissions.

I certainly agree with your comments about political will, another_someone. I am still unconvinced about the 4x figure that my orginal calculation produced!

If you are interested, the reports I used are 'Hot Climate, Cool Commerce' (available at newbielink:http://pdf.wri.org/hotclimatecoolcommerce.pdf [nonactive]; see p5 for the chart showing emissions broken down by gas) and Defra's conversion factors (available at newbielink:http://www.defra.gov.uk/environment/business/envrp/pdf/conversion-factors.pdf; [nonactive] see p6 for the table of greenhouse gas warming multiples).

Moderator: Your URL did not work - the link included the semicolon you used as punctuation - so I changed it to exclude the semicolon.
« Last Edit: 21/07/2007 00:44:01 by another_someone »
 

another_someone

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Methane emissions - how bad are they?
« Reply #8 on: 21/07/2007 01:01:32 »
I am still unconvinced about the 4x figure that my orginal calculation produced!

I suspect the issue being overlooked is that you are quoting emissions, not the percentage of the atmosphere.  As I mentioned above, methane will fairly quickly burn to produce CO2 and water, so even if we are producing enough methane to have 4 times the effect of CO2 that we produce, it does not stay around long enough, so the actual amount of methane left in the atmosphere remains lower.

http://en.wikipedia.org/wiki/Methane#Methane_in_Earth.27s_atmosphere
Quote
This means that a 1 tonne methane emission will have 25 times the impact on temperature of a 1 tonne carbon dioxide emission during the following 100 years. Methane has a large effect for a brief period (about 10 years), whereas carbon dioxide has a small effect for a long period (over 100 years).

As I mentioned above, the Wikipedia page suggests the actual amount of CO2 in the atmosphere is about 220 times the amount of CH4, despite the fact that we are presently pumping out only about 5 times as much CO2 as we do CH4.

Nonetheless, the rise in CH4 levels are suggested to be far faster than those of CO2.

http://en.wikipedia.org/wiki/Methane#Methane_in_Earth.27s_atmosphere
Quote
The methane concentration has increased by about 150% since 1750

http://en.wikipedia.org/wiki/Carbon_dioxide_in_the_Earth%27s_atmosphere#Concentration
Quote
From 1832 to 2004, the atmospheric CO2 concentration increased from 284 ppmv to 377 ppmv, or about 33%, with most of the change occurring since 1970.

OK, they are different time periods, but if, as is claimed, most of the increase in CO2 is recent, the difference in period between 1750 to 1832 should not be that significant.
 

Offline DoctorBeaver

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Methane emissions - how bad are they?
« Reply #9 on: 21/07/2007 09:17:17 »
So what's the situation with regard water vapour? Am I right in assuming they are talking about clouds? If so, then surely we're up that proverbial creek without a paddle.

Then again, has the amount of water vapour in the atmosphere changed that much? I know power stations & jet engines pump out quite a lot; but what other human activities produce significant amounts?

Anyway, judging by the amount of rain we've been having, the water vapour isn't staying airborne.
 

paul.fr

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Methane emissions - how bad are they?
« Reply #10 on: 21/07/2007 09:23:41 »
So what's the situation with regard water vapour? Am I right in assuming they are talking about clouds? If so, then surely we're up that proverbial creek without a paddle.


I think so, Doc. Again, this is something that i think is not made too much of a fuss of (in the media) because we as individuals can do nothing to combat it. But what can governments do about it either?

Again too much information only (no pun intended) clouds the issue.
 

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Methane emissions - how bad are they?
« Reply #11 on: 21/07/2007 09:30:38 »
Back to methane. I remember a couple of years back the New Zealand government tried to take measures to reduce CH4 emissions from cows. Did anything ever come of that? And would it really have made a difference? Or, again, was it a purely political move?

If cows are anything like my horses with regard potent methane farts then it's a serious issue!
 

paul.fr

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Methane emissions - how bad are they?
« Reply #12 on: 21/07/2007 09:38:23 »
Back to methane. I remember a couple of years back the New Zealand government tried to take measures to reduce CH4 emissions from cows. Did anything ever come of that? And would it really have made a difference? Or, again, was it a purely political move?

If cows are anything like my horses with regard potent methane farts then it's a serious issue!

Cattle account for 10% of all methane emissions, as for your question about New Zealand:

Quote

Morning Edition, June 19, 2007 · Most of the industrialized nations of the world have agreed to reduce the amount of greenhouse gases coming from power plants and factories.

But in New Zealand, one-third of these warming gases come from animals, in the form of methane. So researchers are trying something unique to lower New Zealand's greenhouse-gas hoofprint: They want to change what goes on inside the stomachs of millions of sheep and cows.

Just outside the town of Palmerston North is the Taraua Wind Farm, where hundreds of turbines sit on a ridge overlooking the city. The wind farm is a solution to some of New Zealand's problems with greenhouse gases. But the real problem is right underneath the turbines: the sheep and cows that produce methane.

Harry Clark, an animal scientist for AgResearch, is working on a project that tries to reduce methane emissions from ruminant animals. Clark spends much of his time in a shed among a few dozen cows and sheep at Massey University.

These animals don't know it, but they have a gas problem.

Methane warms the planet 20 times more than carbon dioxide. A ruminant animal creates methane when it digests food in its rumen — a part of its digestive system that works like a fermentation tank.

The rumen is overrun with about 400 kinds of microbes, which break down whatever the animal eats. One of these microbes specializes in making methane.

"And that methane, then, is either burped out or it gets absorbed into the bloodstream, and then breathed out through the lungs," Clark explains.

Ninety-five percent of the methane comes out of the animal's mouth, going up into the atmosphere, and warming the climate.

Scientists suggest that putting a stop to the gas problem could be as simple as getting rid of the microbes. Harry Clark's colleague, Ron Reimus, says they can't see any reason to keep those methane microbes.

"We feel that because they're not absolutely required for survival, that you could get rid of them," Reimus says.

One strategy used is to genetically engineer the microbes so they won't make methane. Another is to give the sheep and cows some type of feed that the bugs won't like.

Graeme Maybey runs a 500-acre dairy farm of 350 cows in Woodville, located along the north island of New Zealand.

Maybey says farmers in New Zealand are aware that methane can warm the planet, and they're not against altering livestock to do something about that methane.

"If we can reduce the release of methane in our cattle, as long as it's not going to affect production of milk and meat, then yeah, we're all for it," Maybey says.

Clark's team attempts to achieve this balance between high productivity and low methane emissions. The team measures everything the livestock eat, how much milk they give and how much they weigh.

Most importantly, Clark says, they measure how much methane is coming out of them with a special type of halter.

The plastic contraption partially covers the animal's nose, and through a pipe, it carries breath exhalations through a tube and then to a collector. Clark and his team measure changes in methane when they alter the microbes in a cow's stomach, or when they give the cow a new kind of feed.

Clark hopes that once the methane-making microbes are gone, the energy they consume will stay in the cow or sheep, and help it produce more milk or meat.

"New Zealand relies on the agricultural sector for its livelihood, and so we can't do anything to stop methane," says Clark. "It's got to get done without detriment to the productivity of the animal, that's a given."

The scientists at Massey University aren't there yet, but if they can figure out how to cut livestock's methane emissions, many countries in the world might be willing to pay New Zealand to


http://www.npr.org/templates/story/story.php?storyId=11170158 , this story is avaliable on a podcast or by clicking the link button on the page i have listed.
 

Offline DoctorBeaver

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Methane emissions - how bad are they?
« Reply #13 on: 21/07/2007 09:47:14 »
Thanks, Paul.

So it's burps not farts!  :o
 

another_someone

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Methane emissions - how bad are they?
« Reply #14 on: 21/07/2007 11:15:00 »
So what's the situation with regard water vapour? Am I right in assuming they are talking about clouds? If so, then surely we're up that proverbial creek without a paddle.


I think so, Doc. Again, this is something that i think is not made too much of a fuss of (in the media) because we as individuals can do nothing to combat it. But what can governments do about it either?

Again too much information only (no pun intended) clouds the issue.

No, and it is a key issue.

Clouds cool, water vapour heats.

Water vapour is the humidity of the air, clouds are when that humidity condenses out of the air into water droplets or ice.  Liquid water, or ice (even at high altitude) are not the problem - on the contrary, the clouds bounce sunlight back out to space, so keep us cooler.  It is when you have a sticky, muggy, day, with a clear sky, that you really have the worst problems with water vapour acting as a greenhouse gas, but even on a relatively normal day with average humidity, but clear skies, it will still be acting as a greenhouse gas.

This is what makes it so complex - the same water, in one forms will cool, in another form, will warm.

Incidentally, many of the low carbon fuels (i.e. hydrogen, or methane) will also produce substantial amounts of water vapour as a combustion product; yet they are regarded as environmentally more friendly than their high carbon counterparts which will produce less water vapour (such as coal, or long chain hydrocarbons).
« Last Edit: 21/07/2007 11:17:35 by another_someone »
 

another_someone

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Methane emissions - how bad are they?
« Reply #15 on: 21/07/2007 12:38:39 »
Having said what I did above about clouds always cooling, and not contributing to the greenhouse effect, I realised this can't quite be true.

What I said is true for the daylight hours, where the major role that clods have is to reflect sunlight back out into space; but during hours of darkness, we must have all experienced days when the clear skies of the day have allowed the ground to heat up, and then overcast night time skies have trapped the heat in.  This is exactly what the greenhouse effect is - and so I would suggest that even clouds, during the hours of darkness, will contribute to the greenhouse effect, but during daylight hours will have a cooling effect.
 

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Methane emissions - how bad are they?
« Reply #16 on: 21/07/2007 15:58:06 »
Thanks, George.

I was wondering about clouds at night, but you've cleared that up.
 

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Methane emissions - how bad are they?
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