Wednesday, 23 April 2014

Unlikely causes of acid rain, part 94: Ammonia

From The Metro:
 
Cows and sheep release 37 per cent of the world's methane, which is 23 times as warming as CO2....
 
Yup, that would appear to be true.
 
Livestock also produce more than two-thirds of the world's ammonia, one of the main causes of acid rain...
 
Jeez, I don't remember much from my O-Level chemistry, but that doesn't sound quite right to me.
 
Let's check at Wiki:
 
Ammonia is moderately basic, a 1.0 M aqueous solution has a pH of 11.6...
 
Righty-ho.

30 comments:

View from the Solent said...

I reckon there is a sort of basis for their claim. NH3 oxidises to NO, NO2, NO3 which becomes nitric acid.
But ... That gives rise to nitrate fertilizer goodness.
Another but. Acid rain was mainly the result of sulphur oxides from power stations. It's been scrubbed out of those exhausts for decades.

It does sound scary though, and that's what counts.

Kj said...

About cows being methane emitters; It kind of goes with the territory of being ruminants, digesting fibrous grasses and crops, which take out carbon from the air when they grow. You know, it's a cycle and all that.
A little apropos from the glory days of yore when animals roamed the world and humans were only burning firewood and yada yada:
Overall, methane emissions from bison, elk, and deer in the pre-settlement period in the contiguous United States were about 70% (medium bison population size) of the current emissions from farmed ruminants in the U.S.; data for current (2008) methane and GHG emissions in the U.S. are from the EPA “Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990 – 2008” report. If the high bison population estimate is taken for this comparison, wild ruminants in the pre-settlement period emitted as much methane as the current domestic ruminants in the United States.
From here.
I hope Monbiot among others, who have been a proponent of rewilding, consider this, and that any wild ruminants in these plans be fitted with equipment or regularly supplemented with methane-reducing medications.

paulc156 said...

@VFTS
Acid rain was as you say 'mainly' the cause of sulphur dioxide but also nitrogen oxides. Sulphur dioxide has been largely dealt with but less so nitrogen oxides, or at least they are a problem in the US, not sure about Europe generally.

Again as you point out the ammonia goes from the atmosphere to the ground and breaks down in the soil to nitrogen and nitric acid via bacteria.

paulc156 said...

@Kj. That is a surprising conclusion regarding earlier versus latter day methane levels but in fairness to Monbiot he has already proposed a solution to the possible excessive numbers of deer [we have that now] and bison. They're called 'wolves' and 'lynx'. Brown bear might help too, but might prove an issue with ramblers.

paulc156 said...

Addendum. oops " Acid rain was as you say 'mainly' the cause of sulphur dioxide"... is obviously arse about face.

Kj said...

paulc156: I think you missed the point. Ruminants (and their predators) are and have been a part of earth's biotopes for a while. There were evidently larger amounts of wild ruminants before, and this here seeing now mostly domestic ruminants as a GHG-source kind of misses that they are part of a cycle. They (the ruminants) haven't suddenly found a methane source they are emitting for fun and profit.
Yes, methane has increased in concentration, and this is most likely the increase in rice farming, other soil husbandry practices, gas leaks and so on. More so than the relative increase in domestic ruminants. So it's not a surprising conclusion, being that ruminants are not the only source of methane.

Kj said...

If you ever find that you see the need to "do something" about emissions from wild ruminants, take a breather and think about it for a minute.

Lola said...

Paul156 - from where I sit, wolves and bears would be excellent for ramblers - or the other way about...

paulc156 said...

@Kj. " So it's not a surprising conclusion, being that ruminants are not the only source of methane."


but Kj, you've missed your own point:

'Overall, methane emissions from bison, elk, and deer in the pre-settlement period in the contiguous United States were about 70% (medium bison population size) of the current emissions from farmed ruminants in the U.S'

The point was the comparison between ruminants then and now.
You made it. Seemed surprising to me at any rate. Then again with the increase in meat demand from Asia I'm not sure that the American experience would hold on a global scale.

A K Haart said...

Ammonia in the atmosphere tends to react with acids such as sulphuric or nitric acid to form neutral salts such as ammonium sulphate or nitrate.

In other words it tends to neutralise acid rain, not cause it.

As usual though, there are many complexities such as aerosol formation and potential links with cloud nucleation in the upper atmosphere.

http://www.esrl.noaa.gov/csd/AQRS/reports/ammonia.pdf

Kj said...

Paulc: eh? I was responding to the surprise at the fact that the change from a large wild population of wild ruminants to a large population of domestic ruminants didn't have that large an effect. I'd be surprised if it didn't hold for the rest of the world, as keeping large amounts of low-yielding cattle has been the mainstay of most of the old world for centuries. The warmenists should focus of causes of net increases of GHG's long term, not just sources of emission then and there. Every gram of CO2 that the methane from cattle eventually will be reduced to in about 40-50 years from the point of farting has been removed from the air during the growth of the feed.

Kj said...

And the increase in meat consumption is primarily in monogastric species.

Bayard said...

I get the feeling it's not the warmenists who are behind this bit of "reporting" but the vegetarians.

James Higham said...

Visions of cows flocking overhead and dropping excrement below.

Kj said...

B: probably. Veggies will claim the really outrageous shite.

Mark Wadsworth said...

VFTS, AKH, thanks for sticking to the topic and answering the question. But you're the experts and you don't appear to agree on this one..?

Either:
- NH3 in the air oxidises to NO's and that gets dissolved in rain => more acidic rain, or
- NH3 neutralises already acidic rain slightly.

Hmm. That appears to net off to pretty much nothing.

paulc156 said...

@MW "That appears to net off to pretty much nothing."

It seems pretty clear that ammonia does not cause rain to be more acid but somewhat less acid. Though it appears this effect is only short term and that once deposited on the ground the reaction [neutralisation of acid] is reversed.

See here.

paulc156 said...

@Kj
Well, GHG contributions from agriculture [not just belching/farting but desertification/deforestation etc] is relatively minor [as a proportion of GHG emissions] in the US in comparison to the rest of the world. About 6 times higher in percentage terms. To the extent that this is related to livestock induced methane outputs it might be a concern. Firstly in the US much methane is utilised [so neutralised] for heating/generation purposes unlike much of the developing world and the efficiency of dairy cattle for example in the US is about a hundred fold that of India. So India needs up to a hundred cows to get as much milk as the US gets from one and India's population growth and so on....

Kj said...

MW: sorry for straying.
Paulc: again, eh? Have you been given your figures from veggies? The methane emission figures are without any treatment. And as I said, and you too, countries like India, and large parts of Africa (us too for that matter), have, and have had huge amounts of cattle for centuries. And we can assume that cattle in these parts are also getting more efficient (in fact I know this since I know someone who works with breeding programs that export cow genetics to the developing world), so this can only get better, or at least maintain methane emissions with rising production. And US cows is not 100 times more efficient than Indian, they are maybe around 10-12 times more high yielding. So where is the concern for an increase in GHG potential from ruminants from what has been?

Kj said...

PaulC: and as previously mentioned, any carbon in methane from ruminants is just cycled, so any GHG potential from methane that is more than the sum of the CO2 it will be reduced to, will always be temporary, and unless the feed is synthesized from natural gas, every gram of carbon has been taken from the atmosphere during growth of the feedstock. You guys get this with firewood, why not with this?

Mark Wadsworth said...

Paul, good link. I shall declare this one a no-score draw and cease worrying about it either way.

Kj, Paul, while I was out "on the doorstep" getting signatures for my election form, my Green Party mate from up the road also explained all this methane/land use stuff to me, it makes sense for humanity as a whole to eat less meat, farm fewer animals etc.

But meat tastes nice, so what can you do?

Kj said...

MW: there are issues with livestock, meat consumption and all that. The solution is protecting rainforests from encroachment by soy growers, having decent animal welfare regs, soil management, ditch subsidies. From there on, how much meat we eat should be up to our preferences and the market. Warmenists concerns about cows burping, like their wild predecessors did, is a non-issue IMO.

paulc156 said...

@Kj. Total C is unchanged, but it's in a form with a vastly greater, though shorter lived global-warming potential than CO2.
Obviously this means nada if one rejects the whole GW premise but it has the potential to make matters much worse [climate forcing]in the shorter term [shorter than co2] if one accepts the man made GW premise.
As for ruminants; Beef and cattle milk production account for the majority of emissions in the ag' sector and 'enteric fermentation' contribute 40% of the GWG from that same sector.

Data from FAO. See here.

Mark Wadsworth said...

Kj, agreed.

PaulC, we reject the whole "CO2 causes catastrophic climate change" notion because it is not based on proper physics.

That does not mean I do not care about the environment or pollution, so don't pretend that it does.

By analogy - I love my kids and e.g. worry about them being bullied at school. I do not worry about them being kidnapped by dragons.

You can't say "You don't care whether your children are kidnapped and eaten by dragons? That means you don't love them!"

I have not yet looked into "Methane causes catastrophic climate change" notion, so it might be true, it might be a load of rubbish, no idea.

DBC Reed said...

On the old Two Cultures front, it is good to have the sense of certainty that comes from informed scientific opinion, like Mrs Thatcher believed before she started manifesting her symptoms so badly she became an embarrassment to her Cabinet colleagues.(BTW Max Keiser is now calling her the anti-Christ; seems fair.)
In defence of neo Romantic Monbiot: he only proposed re-wilding of upland regions by tree cover to stop flooding in the valleys.I do not think you could have herds of bison, musk oxen or whatever other ruminants up there.

paulc156 said...

@MW. Not sure where you think I have said or even hinted that you don't care about the environment or pollution. I didn't want to resurrect the whole 'is global warming happening and/or is it man made argument here'. The notion about it not being based on 'proper physics' is only true if you look to the likes of politicians, dodgy blogs and chinwags down t'pub for inspiration.
It's based on complex physics and science not all of it fully understood, so's not the same thing at all.
I merely noted that Kj may shrug off methane emissions as a warming gas by suggesting it's all recycled carbon anyway but that doesn't make 'physics' sense unless you think there is a 'physics' basis for doubting that methane in the atmoshpere exerts a powerful short term influence on temperatures. Or put another way, logically if you're a warming sceptic, you wouldn't worry about methane emissions from cattle whereas if you accept the warming premise you would.

Kj said...

PaulC: no I didn't shrug off methane as a warming gas, I shrugged off ruminant contribution to methane concentrations as a significant concern. As for the statistics, correct, but following our previously agreed upon logic, the only thing interesting is the net increase in that contribution, not point emissions at any one time. The only study I've read about this is in Norwegian, that posited that our ruminant population stopped adding to methane concentration in the late 1930s. From then on, efficiency kept the number of ruminants stabile or slightly declining. I would be surprised if that didn't apply to most of our part of the world, and it will apply to the developing world upon economic growth.

DBC: we should have more bison, deer etc., I'm pro-ruminant. The benefits from converting some shite upland pastures to permanent grasslands for several species of wild ruminants are definetly there, in addition to the tree-cover etc.. But maybe more appropriate in Scotland, the Carpathians etc. than in Somerset.

Bayard said...

Kj, there are still red deer on the Quantock Hills and Exmoor in Somerset, if poachers haven't shot them all yet.

Mark Wadsworth said...

B, deer live in a parallel universe.

A couple of years ago, my son and I had to hang around for half an hour near a farm at the edge of some woodland a couple of miles out of London (long story), and we saw a couple of grey-ish deer* walk past, so I said let's count them.

We counted at least sixty before they disappeared again.

That's the first and last time in my life I've seen deer (outside zoos and parks and so on).

Which is why nobody knows how many deer there are in the UK, thousands, hundreds of thousands, millions. Nobody knows.

* Having googled images, I think they were fallow deer.

Bayard said...

It's probably still true that there's wild deer in every county of Britain except Middlesex. Never seen any here in Wales, though, despite being surrounded by bits of woodland.