Carbon feedback from forest soils will accelerate global warming, 26-year study projects
WOODS HOLE, Mass. — After 26 years, the world’s longest-running experiment to discover how warming temperatures affect forest soils has revealed a surprising, cyclical response: Soil warming stimulates periods of abundant carbon release from the soil to the atmosphere alternating with periods of no detectable loss in soil carbon stores. Overall, the results indicate that in a warming world, a self-reinforcing and perhaps uncontrollable carbon feedback will occur between forest soils and the climate system, adding to the build-up of atmospheric carbon dioxide caused by burning fossil fuels and accelerating global warming. The study, led by Jerry Melillo, Distinguished Scientist at the Marine Biological Laboratory (MBL), appears in the October 6 issue of Science.
Melillo and colleagues began this pioneering experiment in 1991 in a deciduous forest stand at the Harvard Forest in Massachusetts. They buried electrical cables in a set of plots and heated the soil 5° C above the ambient temperature of control plots. Over the course of the 26-year experiment (which still continues), the warmed plots lost 17 percent of the carbon that had been stored in organic matter in the top 60 centimeters of soil.
“To put this in context,” Melillo says, “each year, mostly from fossil fuel burning, we are releasing about 10 billion metric tons of carbon into the atmosphere. That’s what’s causing the increase in atmospheric carbon dioxide concentration and global warming. The world’s soils contain about 3,500 billion metric tons of carbon. If a significant amount of that soil carbon is added to the atmosphere, due to microbial activity in warmer soils, that will accelerate the global warming process. And once this self-reinforcing feedback begins, there is no easy way to turn it off. There is no switch to flip.”
Over the course of the experiment, Melillo’s team observed fluctuations in the rate of soil carbon emission from the heated plots, indicating cycles in the capacity of soil microbes to degrade organic matter and release carbon. Phase I (1991 to 2000) was a period of substantial soil carbon loss that was rapid at first, then slowed to near zero. In Phase II (2001-2007), there was no difference in carbon emissions between the warmed and the control plots. During that time, the soil microbial community in the warmed plots was undergoing reorganization that led to changes in the community’s structure and function. In Phase III (2008-2013), carbon release from heated plots again exceeded that from control plots. This coincided with a continued shift in the soil microbial community. Microbes that can degrade more recalcitrant soil organic matter, such as lignin, became more dominant, as shown by genomic and extracellular enzyme analyses. In Phase IV (2014 to current), carbon emissions from the heated plots have again dropped, suggesting that another reorganization of the soil microbial community could be underway. If the cyclical pattern continues, Phase IV will eventually transition to another phase of higher carbon loss from the heated plots.
“This work emphasizes the value of long-term ecological studies that are the hallmark of research at the MBL’s Ecosystems Center,” says David Mark Welch, MBL’s Director of Research. “These large field studies, combined with modeling and an increasingly sophisticated understanding of the role of microbial communities in ecosystem dynamics, provide new insight to the challenges posed by climate change.”
“The future is a warmer future. How much warmer is the issue,” Melillo says. “In terms of carbon emissions from fossil fuels, we could control that. We could shut down coal-fired power plants, for example. But if the microbes in all landscapes respond to warming in the same way as we’ve observed in mid-latitude forest soils, this self-reinforcing feedback phenomenon will go on for a while and we are not going to be able to turn those microbes off. Of special concern is the big pool of easily decomposed carbon that is frozen in Artic soils. As those soils thaw out, this feedback phenomenon would be an important component of the climate system, with climate change feeding itself in a warming world.”
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Who thinks up these “experiments”? How hot would the air have to be to heat the soil 5C?
Exactly. But not just the top of the soil but all the way down to 60 cm deep.
Air has very little thermal energy, Its density and specific heat are far lower than land or water. If you want to see the effect of air temperature on land, dig a hole on a hot afternoon in mid summer. The soil will be far cooler than the air.
Yep. My dog knows that. Here at 19°S she has dug a hole for a cool spot. She is smarter than Melillo et al.
In the desert just check the temperature a few inches below the surface.
“Who thinks up these “experiments”?”….in tis case someone that can’t find work in their own field
In your world, the soil is the same temperature in July as it is in January?
Why is it when alarmists declare a particular something will happen and it doesn’t, they just declare another particular something will happen and the cycle starts all over again? This pattern of behavior with them is like an open loop system, it just oscillates wildly.
Y’know…..If frogs had wings they may not bust they li’l’ butts when they hop. But then again, they may, regardless.
Open loop or massive positive feedback?
It looks more like massive positive feedback acting on climate science reinforcing ignorance, rather than the negative feedback of the scientific method which mitigates ignorance. When this positive feedback gets out of phase, then it oscillates.
How much extra carbon was sequestered by the extra plant growth on the warmed soil?
“Soil warming stimulates periods of abundant carbon release from the soil to the atmosphere”
AHHHH.. so that’s where all the atmospheric CO2 has come from ! 🙂
Thanks Guys.. ! Can we go back to using coal now ! 🙂
We keep hearing about how this or that thing will cause a massive positive feedback to Climate Change ™. The list gets longer and longer.
Why do these people never consider that if this were true, the climate would get hotter and hotter every time it warmed even a couple of degrees, for whatever reason? It obviously has not in the past, and therefore their conclusions are obviously completely flawed.
Simple logic escapes these people. Common sense is obviously not very common.
there is evidently a positive feedback loop of stupid. these constant open declarations that reason can not prevail should not be ignored. attempting to reason with stupid is stupid ^2.
so forget debate; boot to the head!
When you pay people to be stupid, …
“Why do these people never consider that if this were true, the climate would get hotter and hotter every time it warmed even a couple of degrees”
And why don’t they look at history. There is no evidence of a runaway greenhouse effect in Earth’s history, and both temperatures and CO2 have been higher in the past than today.
If there was no runaway greenhouse effect back then, why should we expect one in the future?
All this cost and hassle to establish that heated soil releases more CO2. I thought the increase in temperature was only going to be 2 degrees C? What if 2 degrees has no affect? And of course this assumes more CO2 is the big bad bugaboo. If it becomes evident that nature has a natural way to offset the increase so it has not impact, what will be the point of this study. Liberals being paranoid that they were destroying the planet.
The CO2 enrichment experiments have been running much longer than this one and indicate productivity increases by 30% or so in a forest. Its difficult to say that this results in more carbon sequestration in a tree forest environment but overall, plants are net absorbing about 25% of our emissions every year and, in 2017 so far, that rate has probably increased to 35%.
Curses! Soiled again.
Well its well known that warming cycles cause forest fires and loss of soil organic matter. It’s the other side of the story we don’t know, whether C02 is an important primary driver of our climate. I more worry about loss of tree cover from deforestation and its affect on cloud formation.
In the next study, we will probably find out that with higher CO2 levels that plants live longer, so there is less material to warm and created emitted CO2.
How to pick the propagandist from the genuine scientist: The use of the manufactured PR term – “Carbon” (not CO2)
I guess the never heard of home heating systems that use buried pipes to warm water and then that is fed in to under floor pipes to heat rooms. It works very well and has nothing to do with warm air.
A ground source heat pump system. There are two common types. One uses vertical loops and the other horizontal loops.
As they say on Law and Order – asked and answered…this ‘researcher’, that has been bilking the granting agency for two decades, already had his own answer to his question and so devised some ‘experiment’ to generate some data for his spreadsheet and explained it with all his preconceived notions….
Let’s just do a quick thought experiment. Let’s say that 26 yeasts ago you got married … to an idea. And, after 26 years of; for better or worse, in sickness or in health, for richer or for (god, I hope not) poorer; that idea wants a divorce. Well, fat chance ‘idea’, you’re not getting one. I put you through college. I sacrificed. If you want a divorce you better gimme what I want.
So, after 26 years the researcher gets to keep the house because ‘idea’ gave him what he wanted out of his marriage of 26 years.
And, just as I have absolutely no trouble believing every single accusation made in divorce courts throughout the land, I have no trouble believing these – after 26 years better come up with something – research results.
Just you wait until the rising heat wakes up all those Trolls underground and they turn against us. Makes just as much sense.
Ahhh,
they “dug up” the soil and put in “electrical cables” to cause
….on average
the temperature to be 5 degrees warmer.
So, what is the temperature gradient between the cables?
I’ll bet the cables warm more than 5 degrees to get the center
of the area “warm”.
Now tell me about the “other plots” what were dug up and not cabled.
Oh? You couldn’t be bothered?
So, if you dig up and cook soil (near the cables) it…cooks.
And remember, they all got paid to do this.
I would have fired them from my research lab since I would not tolerate such sloppy work.
Tell me they don’t give distinguished whatevers tax dollars to do things like this and call it research.
You shouldn’t be surprised …
Tax dollars are frequently wasted on ‘research’. A few years ago a UK university used gov money to run a lengthy study which found that sheep can recognise different human beings – something which any shepherd could have told them and shown them in a few minutes.
What they didn’t study, But I know (and find fascinating) from my own sheep keeping over many years, is that sheep can identify known from unknown humans at several hundred yards distance, upwind or downwind, so scent plays no part. My conclusion is that they can recognise shape, size and the way you walk / move. They also distinguish between known and unknown voices.
Interesting. Learned something. Thanks.
This has been known for quite some time.
“”The man that guards the gate opens the gate for the shepherd. And the sheep listen to the voice of the shepherd. The shepherd calls his own sheep, using their names, and he leads them out. The shepherd brings all of his sheep out. Then he goes ahead of them and leads them. The sheep follow him because they know his voice.”
— John 10:3-4″
Ok I read this and find:
Ph1 – Rapid then stops
Ph2 – Nothing
Ph3 – Something
Ph4 – Something
Surprising, cyclical – NOT
The dates encompasing a phase might be inter-related with dry vs. wet years’ patterns, which are not always of equal duration. I can concieve of more than a linear effect of moisture fluctuations on the something/nothing/plenty phases.
Spring ice melt, any seasonal rain distribution, early or late frost patterns in concert or individually presumably influence cyclical soil micro-organisms, as well as content of dead fall (branch, twig, leaf, seed, deceased bugs’ chitin/fat body/nitrogen, critter excretion)..Meaning,
I’m not surprised either about cycles showing up.
A key aspect, not commented upon in the report, is the depth of the heating cables . Long term measurements in the UK (1996-2004) showed an average 0.8 C difference between air and soil to 1m depth on open land, the soil temperatures being the higher all year round.
Soil in land under trees does not experience radiant heating from sunlight.
It would be useful to have a comparison in their study for soil / air surface interface with its temp raised by 5C at the interface to see how far down into the soil this ‘heat’ propagated. It would be useful to have an assessment of the amount of CO2 released in the study and the increased take up of that by the trees.
However, as with so much climate scaremongering, predictions are made from temperatures which are at and more often above the wildest and most extreme ‘predictions’ of the uniformly failed and thus falsified climate models.
The study results are predictable from other use of soil microbes. Identifying microbes in soil that ‘eat’ hydrocarbons (oil, petrol, diesel etc. ) and then propagating these before injection into the soil is a long recognised and often used method of soil decontamination , albeit one which takes many years. I looked at deploying this in the 1990s.
As an aside, the ever-present Elephant in the room (or dog that didn’t bark if you prefer that simile) is of course nuclear power and the solid refusal by greens / politicians to deploy that……. it shows that the true concern is not CO2 but a determination to De-industrialise the developed nations. Were it otherwise then the Paris Climate Agreement, hailed as a major reduction in CO2 emissions, would not be Increasing global CO2 emissions by some 46% by 2030, as it does.
The microbes that decompose organic matter are more active in warmer temperatures.
That’s why they have cause and effect backwards.
You get warming and then a rise in CO2. Not a rise in CO2 and then warming.
Yep, soil microbes become more active in warmer soil and the result is more CO2 is released as a byproduct of their life cycle. Both the warmer temperatures and CO2 increases contribute to faster and more abundant plant growth. The cycle goes on and on, with ambient CO2 fluctuations for various reasons. Ambient temperature will fluctuate independently for many different reasons, one of which may or may not be transient CO2 levels.
Roflol. They went full retard. You never go full retard !
That would be weapons grade retard?
False premises aside, Jerry Melillo seems to have discovered cAGW signal is drowning in natural variation.
Good grief! They PROVE that warming PRECEDES and CAUSES rising CO2 in the atmosphere and don’t realize the irony of their experiment.
They prove something else as well:
They demonstrated that carbon (dioxide) emissions from the soil drop once readily digested organic carbon (cellulose) is consumed. Then the microbes involved have a population crash and are replaced by other microbes able to digest lignin. There is another period of increased carbon (dioxide) emission. Then nothing more happens.
” In Phase IV (2014 to current), carbon emissions from the heated plots have again dropped, suggesting that another reorganization of the soil microbial community could be underway.”
Or, (more likely) suggesting that the soil has been depleted of available sequestered carbon.
They have actually demonstrated that there is a limit to how much carbon (dioxide) can be released from soil, even when heated far beyond likely (or even possible) levels. Have they made any calculation of the maximum level atmospheric CO2 would reach due to warmed soils? Or are they unwilling to admit that there cannot be a runaway “climate change feeding itself” rise in atmospheric CO2?
SR
When I saw :Woods Hole”, I pretty much tuned out, They went “round the bend” some time ago.
They’ve soiled their reputations now…
One day it dawned on Jerry Melillo that there is not enough money in marine biology, so he joined the crowd doing ‘climate research’.
Marine laboratories had the insightful concept of putting smart people together from different fields spatially close to their environment. It sometimes became tribal and often devolved into specialization of various sorts with some doing research far from their local environment; some became sort of a college.
I have not read the paper, well out of marine science, but ecologists have been long warning about various forms of “pseudoreplication.” Long term studies are valuable, but becoming a significant part of the experiment is one of several common errors there.