Merged Global Warming Discussion II: Heated Conversation

[Red Baron Farms]

If you want to attract attention these days, attach your work to climate change, however spuriously. This is what Savory is doing, with no apparent effort to look at the actual numbers.

You want numbers?

Just to explore the potential possibilities, here is an example of applying the formula above to a soil which, at 100 tons per hectare we increase the soil organic matter by 2% of which 58% is soil organic carbon: a density of 1 g/cm3, 40 cm deep over 1 billion hectares of grasslands would yield 46.4 gigatons of carbon.

If we were to capture 1 ton of carbon per acre per year on the roughly 5 billion hectares of grasslands worldwide, we would remove 12 Gt of C from the atmosphere per year, that is, 6 ppm annually. If gross soil sequestration were approximately 6 ppm/year, after subtracting current annual carbon emissions of 2.5 ppm/year net sequestration would be 3.5 ppm per year.
Restoring the climate

 

[Reality Check]

Again, you are making the same mistake. ...

CapelDodger answered this: The numbers being used refer to rates - of sequestration and of emissions. Grass cannot sequester carbon at a greater rate than it takes it up.

And I will make this point explicitly:

• rate of carbon is produced by us: ~8 trillion kilograms per year.
• sequestration rate by all vegetation is ~2.6 trillion kilograms per year.
  In each year, 2.6 trillion kilograms are absorbed by vegetation, a % of the vegetation dies and the soil captures some carbon.
• There is 240 trillion kilograms more carbon than in pre-industrial times which is an absolute value, not a rate.

 

[Reality Check]

You want numbers?

You want to make Savory's idea look really bad?
"we increase the soil organic matter by 2% of which 58% is soil organic carbon"
But his idea in the video needs to increase soil organic carbon by many-fold not a few percent. Think about it, Red Baron Farms: He has a 1.16% increase on soil organic carbon which comes from vegetation. That is a ~1% increase in absorption of CO2 from the air via that vegetation.

ETA: Maybe not that bad!
The PDF shows that "by 2%" he actually means changing 1% to 2%. So this is a 2-fold increase in the % of soil organic matter.
That would work for 1 year but what about adding 1% more soil organic matter per year so that the soil becomes 1%, 2%, 3%, ... organic matter as time goes by. I am not a soil scientist but I suspect that there is a limit. Maybe this organic matter will decompose again and release the CO2 as happens in peat.

He seems to pull a "1 ton of carbon per acre per year" out of thin air. But he does go onto point out that the validity of these numbers is unknown.

A tiny nitpick, Red Baron Farms - you should not cite a PDF on a slightly commercial web site rather than the scientific literature. At the best we have Savory 's personal opinion. At the worst we have an advertisement .

 

[Red Baron Farms]

That is not what anybody is doing. The numbers being used refer to rates - of sequestration and of emissions. Grass cannot sequester carbon at a greater rate than it takes it up.

That is true. Grass can't sequester carbon at a greater rate than it takes up, but grasslands can be managed in a way that results in greater take up and thus greater sequestration too. Further as I said, the whole statistic is improperly used. First off it is the current biomass of the plant, not a measurement of what that plant produced in the soil. Secondly it is not a measurement of a restored grassland, but instead the currently degraded grasslands. Huge difference and not at all applicable to the discussion. No where in that statistic is it factored in how many times that grass grew, was grazed, and then regrew in a single year. (sequestering roughly an equal amount of carbon as was harvested above each time) When you discuss forests you may measure the dry biomass contained in the wood to get a rough estimate. But when discussing grass it isn't the plant we talk about. It is the soil.

"Up to ... or more" is utterly meaningless. It includes zero and every number above it.

Actually it is not. It simply me being both cautious and reflecting the complexities involved. If you use convert completely sterile ground with no grass at all, then the increase after restoring grassland would be infinity times greater. Convincing Evidence There is your "or more". Some grassland is already being managed by other adaptive rotational management systems which have been proven to work. Switching to holistic management on those lands will not show the same five fold increase. There is your "up too". Then we have the vast majority of grassland that is not managed optimally. There is your average of ~5X +/-, depending how poorly it is managed, if at all.

Even if you multiply all the carbon taken up by grass by 5 you still only get 30% of the current rate of emissions. That's far more than any sensible best case, but there it is.

In a way you have stumbled onto part of the reason we are having such problems now. The current state of affairs is in fact woefully inadequate to solve the problem. We have altered the earth's grasslands to such an extent that they can no longer adequately serve the biologic function of sequestering excess carbon in the creation of fertile mollic soils. 1 we have more emissions, 2 we have less terrestrial sequestration. Thus the overwhelming problem. Holistic management addresses #2 and with human guidance can actually surpass unguided nature. But we have to do this on enough acreage. Restoring 5 million acres here and 5 million acres there, as we have done now, is not enough.

 

[Red Baron Farms]

You want to make Savory's idea look really bad?
"we increase the soil organic matter by 2% of which 58% is soil organic carbon"
But his idea in the video needs to increase soil organic carbon by many-fold not a few percent. Think about it, Red Baron Farms: He has a 1.16% increase on soil organic carbon which comes from vegetation. That is a ~1% increase in absorption of CO2 from the air via that vegetation.

He seems to pull a "1 ton of carbon per acre per year" out of thin air. But he does go onto point out that the validity of these numbers is unknown.

A tiny nitpick, Red Baron Farms - you should not cite a PDF on a slightly commercial web site rather than the scientific literature. At the best we have Savory 's personal opinion. At the worst we have an advertisement .

I originally posted Undersander. That is from a state university extension. They found 2 tons per acre annual increase in harvested dry biomass compared to conventional BMP. If you have been playing along, you should realize the plants shed roughly equal biomass from the roots each time the tops are harvested. (They actually shed more, but that is a whole extra huge subject about another symbiotic relationship plants have with mycorrhiza and certain bacteria) so roughly 1/2 of that (Savory uses 58%) is about 1 ton per acre. So there you have confirmation from an outside source that can't be called "advertisement". But Undersander approaches the profit potential and habitat improvement side, as opposed to Savory's holistic (whole system) POV which includes its effect on climate. It does show however the figures are not "out of thin air". They are reasonable. In fact they may be overly conservative since Savory primarily talks about restoring desertified land which is significantly more degraded (with the potential for greater improvement) than the already lush pastures Undersander was working with in his trials.

Also the 1% is just to show the scale of the sink. In other words, how big is the soil carbon sink in which Savory suggests we sequester 12 Gt of C from the atmosphere per year. The sink size is not a rate. It is a total. Same as the total carbon in the atmosphere is a total, not a rate. He is showing the sink is large enough to hold the excess atmospheric carbon. In fact it is more than enough since we can easily keep adding carbon to the soil sink at least until it reaches 7% or more. My old farm I got to 9% just as an example. Most degraded grasslands at least in the USA are hovering at barely 1% because they are so degraded. (comes from breaking the prairie sod long ago and creating things like the dust bowl as well as conventional grain production in modern times or over grazing and abuse once grain crops no longer will grow etc...)

ETA Just to make it simple. I quoted two paragraphs from the Savory page. The first paragraph describes the potential size of the grassland carbon sink, the second describes the potential rate at which carbon could be sequestered into that sink.

 

[Reality Check]

I originally posted Undersander.

I am talking about what you posted about and from Savory to which I replied:

You want to make Savory's idea look really bad?
"we increase the soil organic matter by 2% of which 58% is soil organic carbon"
But his idea in the video needs to increase soil organic carbon by many-fold not a few percent. Think about it, Red Baron Farms: He has a 1.16% increase on soil organic carbon which comes from vegetation. That is a ~1% increase in absorption of CO2 from the air via that vegetation.

ETA: Maybe not that bad!
The PDF shows that "by 2%" he actually means changing 1% to 2%. So this is a 2-fold increase in the % of soil organic matter.
That would work for 1 year but what about adding 1% more soil organic matter per year so that the soil becomes 1%, 2%, 3%, ... organic matter as time goes by. I am not a soil scientist but I suspect that there is a limit. Maybe this organic matter will decompose again and release the CO2 as happens in peat.

He seems to pull a "1 ton of carbon per acre per year" out of thin air. But he does go onto point out that the validity of these numbers is unknown.

A tiny nitpick, Red Baron Farms - you should not cite a PDF on a slightly commercial web site rather than the scientific literature. At the best we have Savory 's personal opinion. At the worst we have an advertisement .

Savory is talking about all grasslands.
Undersander is about grazed ('harvested') grasslands.

 

[Reality Check]

I originally posted Undersander.

Also, Red Baron Farms, the Undersander you posted was: Pastures for profit: A guide to rotational grazing. Once again not a part of the scientific literature but a nice guide. They assert (and I trust them) that

Rotational grazing also can increase the amount of forage harvested per acre over continuous grazing by as much as 2 tons dry matter per acre.

What you may have missed, Red Baron Farms:

• This is a one time increase caused by the change in grazing method.
• "as much as 2 tons" is not an average of 2 tons. It is a maximum value. The average value will be less and may be much less.
  This may be something Savory realized and thus his value of 1 ton per acre as you assert. Why he then thinks that this change in grazing method can be repeated though is a big problem .
• Not all grasslands are grazed. Much is farmed (think of the American prairies).

 

[lomiller]

That is true. Grass can't sequester carbon at a greater rate than it takes up, but grasslands can be managed in a way that results in greater take up and thus greater sequestration too.

you would need to increase the amount of grass 1700% and then sequester all of it permanently just to offset current emissions. Sequester permanently would mean no grazing, no harvesting no decomposition no soil microbial action, nothing. Even if he's right, which again many people doubt the realistic maximum sequestration would be a tiny fraction of a percent of current CO2 emissions.

 

[Red Baron Farms]

I am talking about what you posted about and from Savory to which I replied:

This is a conversation, not a stand alone post. It would be burdensome and boring to keep repeating the same links over and over. I have to assume my reply addresses the current objection without having to keep restating what has already been addressed. If you are not up to speed, all you have to do is scroll back to my original sources in post # 413

Savory is talking about all grasslands.
Undersander is about grazed ('harvested') grasslands.

Correct. In other words Savory is being very conservative in his figures. This could probably be done using far less than "all grasslands". But I prefer Savory's conservative approach. It gives plenty of "wiggle room". Truth be told, USA could probably manage this alone. The US sink alone is actually large enough. If we did, we would gain a huge long term advantage over the rest of the world in Agriculture, considering the ecosystem services from creating all that new mollic soil. But I doubt you could get everyone in the US to agree to do anything! (without government intervention)

 

[Red Baron Farms]

Also, Red Baron Farms, the Undersander you posted was: Pastures for profit: A guide to rotational grazing. Once again not a part of the scientific literature but a nice guide. They assert (and I trust them) that


What you may have missed, Red Baron Farms:

• This is a one time increase caused by the change in grazing method.
• "as much as 2 tons" is not an average of 2 tons. It is a maximum value. The average value will be less and may be much less.
  This may be something Savory realized and thus his value of 1 ton per acre as you assert. Why he then thinks that this change in grazing method can be repeated though is a big problem .
• Not all grasslands are grazed. Much is farmed (think of the American prairies).

No that is an annual figure. Read again in context. Absolutely agree not all grasslands are grazed. Again you are making a point already addressed. Farming grassland by destroying it in favor of annual crops to feed livestock in CAFOs is a major part of the problem.

 

[macdoc]

Plant grass, eat kangaroo ...

 

[lenny]

The "more research is required" policy has been disastrous in many ways, but it has actually led to more research being done.

So I,of course, agree deeply that we have learned many things about many things. But in terms is the targets of the "more research required" research, have we really learned that much? Other than that the models have not proven the basic insights of the 80's and 90's wrong? That there is a high risk we are in serious trouble and no easy way out?

What do we know about the likely details of the planet in 2080 (for adaptation)

What new have we learned in terms of the scientific case for mitigation that we did not hold probable twenty years ago? ( when atmospheric concentrations were lower and massive infrastructure investments had not the been made?)

By the time things settle down we'll have climate science nailed.

Do you think we will ever have climate science nailed? (the science of the earth system, not just the every particular bit we think to focus on.)

I'd offer even odds that, in extrapolation, the planet will continue to throw up surprises for science for as long as we're around to do science.

 

[DC]

So I,of course, agree deeply that we have learned many things about many things. But in terms is the targets of the "more research required" research, have we really learned that much? Other than that the models have not proven the basic insights of the 80's and 90's wrong? That there is a high risk we are in serious trouble and no easy way out?

What do we know about the likely details of the planet in 2080 (for adaptation)

What new have we learned in terms of the scientific case for mitigation that we did not hold probable twenty years ago? ( when atmospheric concentrations were lower and massive infrastructure investments had not the been made?)



Do you think we will ever have climate science nailed? (the science of the earth system, not just the every particular bit we think to focus on.)

I'd offer even odds that, in extrapolation, the planet will continue to throw up surprises for science for as long as we're around to do science.

we have learned enough to take action, we do no longer need to wait and research if it might have been other things. We know what the problem is. and we dont have to spend that much time and money researching it, we rather should put more effort , time and money into mitigation.

like we do not need further research into smoking increasing the risk of getting lungcancer. despite the fact that we still do not know how that actually happens. we know enouhg to recommend not smoking and even make laws protecting people that do not want to smoke.

the same goes for the climate system, we still gave lacks of understanding on alot of details, but we do know enough to take action now.

we are like drug addicts hoping that the next study shows our addiction is not so problematic as we believed it to be.

 

[macdoc]

We don't know everything about aerodynamic theory but we know enough to design and fly planes.

There is ample evidence both theory and observation to know that adding fossil carbon to the atmosphere will cause the planet to warm. That's the reality and we are acting to slow that process.

The outcome of that warming and the associated other pollutants that may slow or enhance the speed of the warming is a very difficult task to unravel.

 

[lenny]

Thanks DC,

we have learned enough to take action, we do no longer need to wait and research if it might have been other things.

In part, my point was we almost certainly knew that much in the 90's. so I do not disagree with you, I was asking a different question.

 

[lenny]

hi macdoc

There is ample evidence both theory and observation to know that adding fossil carbon to the atmosphere will cause the planet to warm.

Agreed. But we knew that in the 90's, don't you think? And had a pretty compelling science case in 79, or shortly thereafter.

What have we learned in the last, say, ten years that significantly bolsters the case for mitigation? I don't mean to suggest it needed strengthening as a basis for policy.

I agree with your comment on the difficulty of predicting the outcome even knowing the emissions; which suggests we have not learned much of use in preparing for detailed adaptation on small scales (regional) in the 2080's.

Thanks again for maintaining your ever updated list.

 

[CapelDodger]

So I,of course, agree deeply that we have learned many things about many things. But in terms is the targets of the "more research required" research, have we really learned that much? Other than that the models have not proven the basic insights of the 80's and 90's wrong? That there is a high risk we are in serious trouble and no easy way out?

We've learnt a great deal more about the oceans, which have been sadly neglected in the past except in the North Atlantic (where the MAD subs lurked). Then there are the ice- and sediment cores which probably wouldn't have been taken if climatology had remained palaeoclimatology, which it pretty much was until the 80's.

What new have we learned in terms of the scientific case for mitigation that we did not hold probable twenty years ago? ( when atmospheric concentrations were lower and massive infrastructure investments had not the been made?)

It may be knowledge for its own sake, but none the worse for that.

More research in lieu of action has been disastrous, but that doesn't devalue the research itself.

Do you think we will ever have climate science nailed? (the science of the earth system, not just the every particular bit we think to focus on.)

I do. What we're focussing on includes oceanography, meteorology and glaciology, and we'll have a mass of real-time observations to work with (rather than proxies). There's a vast experiment going on, and we're all in the middle of it.

What effect will an ice-free summer Arctic have? We're going to find out. How do the great ice-caps respond when they're out of equilibrium with the climate? And permafrost? Again, watch and see.

I'd offer even odds that, in extrapolation, the planet will continue to throw up surprises for science for as long as we're around to do science.

That bet would never pay out .

 

[CapelDodger]

"More research is needed" was certainly an excuse for inaction, but what's relevant there is that inaction was the desired policy of those in power. China and India, for instance, have used a different excuse - "you go first" The general failure of governance - national and international - is down to flawed institutions and a flawed species, neither of which are good at risk-evaluation.

I think we'll come out of this with much better institutions, but I won't be around to see it.

 

[macdoc]

solution from grasslands?? no

“…people who understand far more about carbon than I do calculate that for illustrative purposes, if we do what I’m showing you here, we can take enough carbon out of the atmosphere and safely store it in the grassland soils for thousands of years, and if we just do that on about half the world’s grasslands that I’ve shown you, we can take us back to pre-industrial levels while feeding people. I can think of almost nothing that offers more hope for our planet, for your children, for their children and all of humanity…”

While it is understandable to want to believe that such a dramatic outcome is possible, science tells us that this claim is simply not reasonable. The massive, ongoing additions of carbon to the atmosphere from human activity far exceed the carbon storage capacity of global grasslands.

http://www.realclimate.org/index.ph...ne-commentary-on-savory-ted-video/#more-16057

From those that understand the situation.

 

[aleCcowaN]

"Using FAO’s data and definition, it is possible to estimate the world area of Pasture and Fodder Crops at 3.5 billion ha (35 000 000 sq km) in 2000, representing 26% of the world land area and 70% of the world agricultural area (Table 1.1)" (source: FAO)

C yearly emissions (in CO2): 8.3 GT
half of grasslands: 1.75 Gha
needed C absorption: 4.75 T/ha (about a pound per square metre)

I can get that in my garden by adding 4 or 5 mm of dried mulching, including what is necessary to replace the degrading humus, so it looks attainable ... wait a minute! The typical no-till soybean cultivation on soy stubble here (Wiki image shot in Buenos Aires Province, coords in the page), gets the soil wasted not so quickly and gets some 4 tons of soy beans -using some 200 kg of fertilizer in a year with reasonable rain- from which some 1.5 T is Carbon. So it is apparent that soybean cultivation using fertilizers to simply ditch the harvest in the very soil where it's grown is barely enough to simply absorb the new waste carbon mankind throw each year into the atmosphere. By the way, the farmer wants the fourteen hundred dollars he or she would be losing by doing that. The Chinese want the oil, the hens want the pellets made with the crushed beans if they are to lay eggs. Where am I going to get the ham? But they were talking of grasslands. OK.

If someone could explain with figures side by side a model of grassland sequestrating no less than 2 Tons of Carbon -not carbon dioxide- a year, please do!

I reject beforehand any figureless argumentation on that. Most of all if it comes from the same kind of reasoning that made an usual poster here to say that certain farmer had succeeded increasing the carbon content in his farm just with the manure of his cattle though admittedly he got almost all the fodder elsewhere.

As seen in the last few dozens of posts in this thread, it all boils down to the same old bad joke:

"-I have good news and bad news
-The good news first
-There are 1,429 solutions to our problem
-And the bad news?
-We must use all 1,429 solutions at the same time"

Well, carbon sequestration in soil, including grassland, amounts just for a couple dozens of those 1,429 solutions. And about RealClimate's «although these criticism quickly followed Mr. Savory’s presentation and are broadly supported by the available science, his sweeping claims have continued to resonate with lay audiences», I bet the lay audiences were formed mainly by urbanites.