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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Oh Dear. But the fools never thought nor could explain that C, CO, CO2 and CH4 concentrations in the atmosphere have nothing to to with atmosphere temperature, though it is the claim … yet again. Sad.
I’ll say again, if the feedback to global warming were “positive”, the earth would long since have fried to a crisp. Even if forest soil did produce more CO2 in response to warming, something else out there simply must be operating in a negative forcing direction. Otherwise, none of us would be hear to puzzle over global warming.
It could also be that CO2 is totally insignificant in relation to global temperature fluctuations.
This is a natural phenomenon, it was there in the past, it is there now and will be there in future. Deforestation and re-forestation change the balance. Under the forest cover, the so-called global warming of 0.15 oC [locally warming may or may not exists] will have practically zero effect on soils under the forest cover.
Dr. S. Jeevananda Reddy
Really. We have black clouds of particulate carbon rising from the forest soils?
That is inconsistent with the laws of Physics.
If the soil temperature ever rises by 5 degrees celsius, that would be the average of the daytime & nighttime temperatures, right? If so, then the average daytime temperature would have to be maybe 7.5 degrees higher than today’s, which is unlikely.
I read in the history books Romans brought elephants over the Alps some 2,000 years ago. Must have been pretty warm back then. How come we are all still here?
It was Hannibal of Carthage who went over the Alps. It was still cold there even then as research indicate that the Elephants suffered the trip over it,with some who died.
What is it with these people?
Scientists they are not!
A single conifer forest with some artificially heated plots of unspecified dimensions in a convenient to them, latitude limited location to assess the CO2 emissions from heated “forest” soil.
Then model the results from this artificial situation and extend those same modelled results across the whole planet and its immense array of soil types to pretend that they have derived the soil emission tonnages of CO2 from a modelled and a supposed but unproven claimed planetary warming effect on the soils of the planet.
From the 3 million square Miles area “The Soils of Australia”
TYPES OF AUSTRALIAN SOILS [ major headings below ]
[ http://www.abs.gov.au/ausstats/abs@ur momisugly.nsf/Previousproducts/1301.0Feature%20Article801966 ]
Stony and shallow soils
Soils of the alpine and perhumid zones. [ 6 major soil types ]
Soils of the humid zones [ 6 major soil types ]
Soils of the seasonally humid zones [ 5 major soil types ]
Soils of the semi-arid zones [ 3 major soil types ]
Soils of the arid zones [ 3 major soil types ]
The gilgai phenomena.
And they all emit the same amount of CO2 when artificially heated!
Yeah! Right!
No wonder a lot of science and its practitioners are being looked upon by an increasing percentage of the public with an increasingly jaundiced attitude towards their claims.
Icy conditions are so frequent in the north, a local meteorological institute (FMI) has defined five different types of road ice to improve safety. Some roads are equipped with sensors measuring both the air and road surface temperatures – results are streamed on the internet and roadside panels. Turns out roads are often naturally warmer than the air, can be 5 °C. Cities too, but also similarly to some random patches of deciduous forest at the Harvard Forest in Massachusetts.
It’s doubtful FMI would have used scarce resources for electric outside heating over decades or hired a marine biologist to take samples, analyse and report carbon content of several cubic meters of forest soil up to 60 cm depth. Already soil sampling would be quasi-impossible in the ever expanding tree-root network littered with granite rocks and boulders. Let alone reporting any meaningful results out of it. But perhaps in Massachusetts road safety is under control, there is limitless cheap electricity and soil is more like seawater.
This ‘resarch’ produced the most important thing , a scary headline. For that not good science was required. Which is just as well given they are not able to do this in the first place.
But the reality is that there is no real evidence that CO2 has any effect on climate. There is plenty of scientific reasoning to support the idea that the climate sensivity of CO2 is zero. The AGW conjecture depends on the existance of a radiant greenhouse effect caused by trace gases with LWIR absorption bands but such a greenhouse effect has never been observed anywhere in the solar system. The radiant greenhouse effect is science fiction. Hence the AGW conjecture is science fiction as well.
I will make my usual comment in cases like this: if this was an important process in the real world it would have been noticeable during the previous Eemian/Sangamonian interglacial which was considerably warmer than the present one, particularly at high latitudes.
It wasn’t.
So once again human CO2 is demonic, and temperatures of the so-called “anrhropocene” are evil. Or else how does one explain the way that the soil cycle never contributed to climate apocalypse in prior warmer periods, or even warmer periods with more ppm CO2?
The only measurable result of the recent period , in reality, is that soils and plant life are are increasing significantly.
Why do political greens hate green life?
Interesting experiment – and numbers.
3,500Gt of carbon
Do check my calcs..
I say farmland occupies 10% of the Earth’s area and = 5E13 square metres
Good soil (A horizon) will extend down to 2 feet depth. Call that 0.666 metres
Lets assume it is 50% by volume organic material (I’d say that that is on the low side when looking on forest floors.
Lets give this stuff the same density as wood or reasonably compacted cellulose (as farmers make for their cows = hay or silage) give it a density of 0.666 tonnes per cubic metre
That gives 1.1E13 tonnes
If burned, that would yield a shade over 2E13 tonnes of CO2
Do we double that because of what’s locked into permafrost, about another 10% of Earth’s area?
So. Take a spade (or any digging implement of your choice) outside into the garden, field, forest, golf course, park or where-ever and look for it.
For the most part you will find that it’s not there.
Where did it go?
At this point I’d recommend you to have read 2 books in particular – David Montgomery’s ‘Dirt-the erosion of civilisation’ and also, surprise surprise, Lierre Keith’s ‘The Vegetarian Myth’
Because, you and your spade or backhoe loader should have found a layer of ‘A Horizon’ typically 1 inch thick for every 500 years since the ice retreated from your chosen digging place.
In poor situations (cool, cloudy, high rainfall) it may be only 1 inch per 1000 years or sometime 1 inch per 200 years in more temperate places.
And is what should be thrown with all your might at folks who say about tree-burning and Biomass “Ah but, it will all turn into CO2 anyway”
Just ask them where dirt comes from. Ask why, if/when they feel romantically inclined and get a potted plant as a gift for their ‘love’, what is that stuff the plant is potted in?
Not rocks, sand & gravel is it?
Why not?
In her book, Keith comes up with the line that: “Plants grow through the action of soil bacteria chewing up old/dead/buried plants and the living plant(s) use their roots to suck up the resulting soup”
or words to that effect – Actually extremely good food for thought
Why?
At this time of Northern Hemisphere year (September), something happens on farms, fields, parks etc etc or any place where perennial grasses are growing.
Farmers call it “The Autumn Flush”
It is where fields or grasslands that have cropped and or grazed by animals through the summer put on an epic spurt of growth.
And this happens without any input from The Farmer or anyone/thing else. Curiouser and curiouser.
And, putting myself into Inquisitive Mode, have enquired of a great number of long established family farmers what they think is going on.
None of them know. They don’t ‘need to know’ Its just something that happens.
(If these guys don’t know, we really are in Shit’s Creek)
Now. Those of us grappling with the definition of what or where The Surface Of The Earth actually is will appreciate what may be happening inside the Autumn Flush.
Because, and ss these scientists have done, curious and inquisitive types may have placed a thermometer under a couple of feet of dirt and be comparing its readings with another identical thermometer placed 5 or 6 feet above the surface. Such as those pretty little white boxes you get.
The 2 thermometers follow entirely different temperature profiles, Both daily and annually.
(Quite effectively destroying the idea of Green House Gas Heating, Why the buried one reads a constant +20degC while the above ground one reads +5degC at night and +30degC at 3 in the afternoon. How does GHG theory explain that. Only by hurling insults as we all know.)
As it happens, the underground thermometer reaches its peak in late August into September and we know from school (we do, don’t we?) that bacterial action follows roughly the same temperature rules as chemical reactions – they double in speed/rate for every 10degC temp increase.
Hence the soil bacteria are extremely active in late August, producing not only CO2 but ;large amounts of Humic Acid – that vague mixture of organic acids that erode the mineral fraction of dirt and provide the ‘soup’ that Keith talks about.
(Innit amazing how stuff fits together – we may get The Emperor off that charge of Indecent Exposure before long)
Now, back to Autumn Flush.
If/when humans were not around to relentlessly burn everything, the biomass produced would have fallen back into the dirt and been buried, ideally helped by the big trampling feet of ruminant critters.
And thus was/is the process of Soil Organic Carbon
Right. Temperature and feedback
Organic stuff (sugar, starch cellulose and lignin) is simply made of carbon chains with water molecules attached,
Water, due to hydrogen bonding, has a humongously epic affinity for itself. Why are cotton bath towels so much better than polyester fabrics?
The buried organic stuff can do nothing else but get wet from being rained on and is thereafter very reluctant to release that water. Organic rich soil retains water infinitely better than sand or gravel do.
(Wonder if that may help with ‘flood prevention’? No matter)
So, if you want to increase the temperature of this organic dirt, you need *vast* amounts of energy. But assuming you do, the bacteria kick in, produce more plant material that retains more water and requires ever more energy.
Where the fook is all this energy coming from?
My bad. Buried electrical cables of course. How stupid of me.
But, adding huge energy to the dirt also implies adding extra energy to The Atmosphere.
Because The Atmosphere is in very close contact with a perishingly cold thing/place (Outer Space. The Cosmos) it will dump that extra energy very quickly. Not least because of the increased steepness of the thermal gradient. The thermal gradient is a greased pole and photons of energy have many of the properties of eels, except they move even faster. At Light Speed in fact.
Given a constant input of energy from the Sun, this extra loss means a cooling effect and if its done via radiation, the greased pole gets steeper and greasier following a quadratic squared law. It gets very steep very quickly.
Now some feedbacks are starting to become visible, feedbacks that this guy here cannot see. He’s yet another trapped in a bubble of Magical Thinking.
His even greater fail is to miss what is, in common with plants themselves, The Limiting Nutrient for the soil bacteria.
Water soluble nitrogen.
It’s being thrown around, since end of WW2, with great gusto by farmers and is also raining down from the sky as a consequence of us burning so much stuff. And high voltage electrics & DC motors/generators.
So we see, a HUGE store of carbon and a method for releasing it, increased temps and nitrogen. Worse of worse, nitrogen not only takes away the soil carbon but also the water it retained. Things cam warm up while losing energy and CO2 levels rise. The CO2 is a symptom of rising temps, not the cause.
We are drying out the planet,. We are weathering the soil, which was really old and highly weathered anyway. It is low on the nutrients, that ‘soup’ Keith mentions in her book. After 10s and 100’s of millions of years, most of the soup has washed away into the ocean. From where it wont return. Just like CO2 and the Titatnic. Once in the water they ain’t coming back
So, you want Ice Ages
Ageing old car mechanics will know the ‘symptoms’ an engine that starts but runs for just a few seconds. Typically due to fuel shortage or starvation.
That describes ice ages. Fuel starvation.
Plants grow for a short while (interglacial) then stop/die when their fuel/food is used. The engine stops while the fuel slowly returns = The Ice Age (The glaciers sweep away the old stuff, they ‘clean the filter’)
That is the cycle Earth is in right now. Spluttering then stopping. Spluttering then stopping.
But short of some truly huge volcanic event. no new food (soup) is forthcoming and the engine will stop completely.
Just like what happened to Mars
“Plants grow for a short while (interglacial) then stop/die when their fuel/food is used. The engine stops while the fuel slowly returns = The Ice Age (The glaciers sweep away the old stuff, they ‘clean the filter’)”
So what kept the engine going for the 250 million years between the Permo-Carboniferous ice age and the current one?
My pasture is grazed by cattle & does not regrow until the next rainy season. I imagine “fall flush” allyded to is actually helped by “anything/someting”; presumably moisture &, if grazed, manure.
Incidentaly, both bacteria & fungi average 48% carbon. However, fungi average just 6% nitrogen & bacteria average 12.5% nitrogen. Fungi only average 5% nucleic acid, because their hyphae (branching) have no biological activity in large area). Bacteria average 23% nuckeic acid.
Plants can encounter predominately fungal or bacterial micro-organism soils outside. However, rampant bacterial activity produces organic acids (ex: butyric, valeric) that can be inhibitory to tender aged/germinatng plants. This is why “immature” compost, with it’s abundant bacterial substrate, is not used; aside from any issues of viable weed seeds or pathogens.
Since “business as usual” won’t warm the atmosphere by more than 2° C, the soil will remain well below the 5° C limit.
A similar experiment on permafrost in Alaska found no evidence of a soil-based carbon feedback.
The temperature was more than 5 degrees warmer than now in most of the Boreal taiga and tundra zone during the last interglacial. And nothing much happened.
Yep… Well, sea level was a little higher… Orherwise, not much difference between the Eemian/Sangamonian and the Holocene.
Funny…
Eemian: warmer with higher sea level… lower CO2.
Holocene: cooler with lower sea level… higher CO2.
Hmmm… time to break out Inigno Montoya… 😆
How about just monitoring the soil as is and determine the amount of carbon released vs sequestered in the soil or the surrounding plant material? More vegetation or larger tree trunks or more microbial biomass in the soil? Seems rather silly to warm soil up when that seems rather unnatural. What really did happen without artificially changing the soil warmth?
Yes…how much did the unheated soil warm over the last 26 years, if at all?
And this is a problem?
It’s making deserts greener increasing crop yields and affecting temperature not so much as anyone would notice.
Spellcheck: ARCTIC, not ARTIC….
“How To Make A Desert”?
Not a definitive experiment by any means. Way to many uncontrolled variables, including- how were the electrified plots chosen, were the plots sampled to ensure uniform initial conditions, did all plots get electrified but only some got tested with power(soil disturbance, how many and how large were the samples(soil disturbance), were all plots allowed to equilibrate(say 15-20 years) after electrification but without heating, was solar irradiance measured on all plots through out the experiment(i.e. did some trees shade others more). was the timber growth measured or estimated, etc.
Perhaps what was measured was- how much does widespread soil disturbance disrupt the soil ecology?
This article is spot on and yet another reason to get on your knees and thank God for the IPCC 2015 Paris climate agreement.
We are making progress my sceptic friends and will soon welcome the US black sheep back into the fold once Fatberg and his grasping family have been kicked out of the WH, and the arch-sceptic Pruitt imprisoned for pandering to the corporate lobbyists instead of protecting the welfare of American citizens.
I’m guessing you haven’t bothered to read any of the critiques of this “study”.
It reached the conclusion you support so it must be correct.
Ivan, it was MUCH warmer just 6,000-10,000 years ago,yet nothing like the study claims happened at all.
The study is a joke since they introduced artificial methods not found in the Holocene time.
Delusional much?
We are indeed making progress, ivanskinsman!
This article is spot on:
Breitbart Exclusive: EPA Document Proposes to Eliminate Clean Power Plan ‘in Its Entirety’
“The Environmental Protection Agency (EPA) plans to repeal the agency’s Obama-era climate change program, the Clean Power Plan (CPP), “in its entirety,” according to a document obtained by Breitbart News.”
http://www.breitbart.com/big-government/2017/10/06/exclusive-epa-document-proposes-eliminate-clean-power-plan-entirety/
What about the other soil study that concludes the opposite to this soil study? They both can’t be “spot on”, can they?
‘Tipping points’. ‘Worse than previously thought’. ‘Catastrophe!’ Blah blah blah.
Every last one of these ‘studies’ that predicts positive feedbacks and ‘tipping points’ is imo a deliberate deception. There’s no tipping points, no positive feedbacks leading to ‘runaway’ anything and no pending catastrophes, imminent or otherwise. They peddle certain catastrophe at some indeterminate future point to maintain the gravy train. No other reason.
If this so called feedback is so devastating, why didn’t we all die the many, many times the world was as much as 3 to 5C warmer than it is today?
Exactly. It’s a totally bogus construct that’s effectively been falsified a million times over. Surprised an authoritative voice hasn’t nailed this one by now.
The beginning of every interglacial over the last 5 million years has produced warming far greater than what humans could ever do, including the one we are in currently. Every single time, the warming was great for the biosphere. There has never been any indication that the warming was bad for life, or any sign that it might ‘runaway’, and there isn’t any indication of that now!
I think it is time for ‘pro-CO2’ bumper stickers.
This isn’t an ‘experiment, it’s an exercise in stupidity! For openers, underlying everything is the assumption that CO2 causes global warming, despite proof from ice cores that rise in CO2 ALWAYS lags warming and proof from shorter term measurements that show the same thing. So from the outset, the conclusions are not credible, no matter how hot you heat the soil.
Secondly, where are you going to get 9F (5C) of warming to get 17% more CO2? That amount of warming would have to be generated by some natural process which makes the ‘experiment’ pointless.
Thirdly, is a 17% increase in CO2 a meaningful increase? The total increase in CO2 during the most recent warming (1980 to 2000) was 0.008%–is a 17% increase of 0.008% significant? The changes in CO2 are so miniscule that even doubling of CO2 is insignificant. If you double nothing you still have nothing!
Bottom line — this isn’t science, it’s dumber than dumb!
Not to worry. Stanford researchers coincidentally reported today that soil will slow global warming.
So, we have a the science is settled! competition: soil slows global warming cancelling out soil exacerbates global warming.
It seems the most rational position is that soil won’t do anything we need to worry about. 🙂