Amount of carbon released from the Earth is about the same as released by deforestation
- Ian Johnston Environment Correspondent
- @montaukian
- Tuesday 29 August 2017 19:25 BST
The degradation of the Earth’s soil by humans has been an environmental catastrophe on a similar scale to the deforestation of much of the planet, a new study suggests.
Experts estimated that 133 billion tonnes of carbon has been removed from the top two metres of soil since farming began some 12,000 years ago, about the same as the total amount lost from vegetation.
However the figure is still dwarfed by the 450 billion tonnes of carbon emitted since the Industrial Revolution began and humans started burning fossil fuels on an unprecedented scale.
Soil is obviously vitally important for the growth of crops that feed humans and livestock. Concern has been growing what some refer to as the “soil fertility crisis”, a problem that can be masked by the use of artificial fertilisers.
Carbon released from the soil also contributes to global warming.
But the researchers suggested the figures showed the potential for soil to absorb carbon, something that could be used to reduce the level of the greenhouse gas in the atmosphere by using different agricultural techniques.
Writing in the journal Proceedings of the National Academy of Sciences, they said: “The incredible rise of human civilizations and the continuing sustainability of current and future human societies are inextricably linked to soils and the wide array of services soils provide.
“Human population and economic growth has led to an exponential rise in use of soil resources.
“The consequences of human domination of soil resources are far ranging: accelerated erosion, desertification, salinization, acidification, compaction, biodiversity loss, nutrient depletion, and loss of soil organic matter.
“Of these soil threats, loss of soil organic matter has received the most attention, due to the critical role [it] plays in the contemporary carbon cycle and as a key component of sustaining food production.”
The total figure for the lost carbon was estimated at 133 billion tonnes, saying: “These soil-organic-carbon losses are on par with estimates of carbon lost from living vegetation primarily due to deforestation.”
The researchers found the UK, northern and central Europe, parts of China and the US corn belt were particular hotspots.
This is partly because of the high levels of carbon that would have originally been in the soil in these areas, but also the type of farming typically practised there.
Unsurprisingly, losses from cropland were significantly higher than from land used for grazing animals. But arid grasslands were also vulnerable if they were over-grazed, leading to significant erosion.
One of the researchers, Dr Jonathan Sanderman, of the Woods Hole Research Centre in Massachusetts, told the website Carbon Brief: “Considering humans have emitted about 450 billion tonnes of carbon since the industrial revolution, soil carbon losses to the atmosphere may represent 10 to 20 per cent of this number.
Read the rest of the story here.
HT/DMH
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This sounds to me like something from the Bureau of Useless Information.
Finally, an article on the real problem. It is hardly a catastrophe that we have to solve within 5 years or we’re all going to die. But when we work on it, we improve soil fertility and increase the nutrient content of foods.
However, there is so much lying in anything touching on “climate” or “carbon” that I question the ratios given. They could be truthful, but they are just as likely to be distorted in favor of the attack on fossil fuels.
133 billion tonnes, huh? How do they know it wasn’t 132 billion tonnes or 134 billion tonnes?
Around 10 billion people owe their lives to agriculture. That works out to 13 tons of Carbon (or is it CO2) per person. You need much more to cook over your lifetime.
Study guesses
1. Carbon in the soil is in no way necessary for farming, it is just a convenience since it (usually) makes soil more easy to work. Many of the World’s best agricultural soils are virtually carbon-free.
2. Farming by definition means removing nutrients from the soil. These must therefore be replaced, at least in the long term, by weathering, manuring, artificial fertilizers and/or growing nitrogen-fixing crops.
3. The areas mentioned in the press release “UK, northern and central Europe, parts of China…” are arguably the very areas where farming has been practised for the longest time (4000-6000 years) without any serious decline in fertility.
An inconvenient fact is that organic farming/vegetarianism can end up depleting the carbon content of soil. An acre of topsoil weighs about 1000 tons, and has an organic matter of between 3 and 5 percent.
Organic farming prohibits the use of herbicides, so requires more cultivation to kill weeds as well as preparing seedbeds. Every time soil is moved the aeration results in bacteria breaking down organic matter thus releasing carbon dioxide to the atmosphere. The organic soils of the fenlands in East Anglia have shrunk due to oxidation following cultivation by 10 feet and more in the past 150 years.
Vegetarianism/veganism has no use for animals in the farming system, so there is no manure produced to replace organic matter in the soil. Fertility building crops, as they call them, reduce the efficiency of utilisation of land for crop production.
There also remain the vast areas of grassland in dry and hilly areas unsuited to crop cultivation that would also go to waste.
Everything is a lot more complicated and interrelated than some would have us believe. The one fact that is indisputable is that we will have 10bn people on the planet to feed.
Unfortunately “fertility building crops” only replace nitrogen, not phosphorus, potassium or calcium. These are usually replenished by manure or offal. Try that without any animals….
On second thought it might not be a problem. If all farming goes organic there will be lots of dead bodies available rather quickly.
StephenP,
As I was an organic gardner for over 25 years in my own (small) garden, what you write doesn’t make sense. Organic gardners use any kind of organics, like peat and cut grasses from lawns to spread between crops, so that little to no tilt is needed and that gives a much better water management, both for too much and to low water. Organic farmed soils should have increased organic content, far more than soils only fertilized by minerals and synthetic nitrogen.
Further, raw phosphate and Ca/Mg carbonates (often from seaweed) are used, as that is used by the plants only if needed and not much is wasted by leaching into groundwater from soluble monophosphates. Seaweed carbonates also contain a lot of trace elements. Raw phosphate also uranium, but for organic farming, low-uranium ore is used. For monophosphates, uranium and other heavy metals are removed in the process.
Real vegan would give problems over long periods as that doesn’t return enough nitrogen, although crop rotation with nitrogen fixators as fertilizers may help somewhat. Vegetarians do use milk and cheese, these animals do give a lot of nitrogen, but that never may be applied directly on any organic soil: only after mixing in with other organics and complete composting…
I don’t think that organic alone can feed the world, as the average yield of organic is about 20% lower than of “classic” agriculture and more expensive as it is more labor intensive.
As a matter of fact in Northern Europe accumulation of carbon in the soil is a serious problem for forestry. Before planting trees it is often necessary to dig or plow through the accumulated layers of forest litter to expose the (carbon-free) mineral soil the tree-plants need to take root.
And there is literally millions of square kilometers of peat bogs in North America and Eurasia. Almost all of that peat (=carbon) has accumulated since the end of the last glaciation. 133 billion tons of carbon is small change in comparison. In Sweden alone the growth of peat is estimated at 20 million cubic meters per year, multiply that by Russia and Canada….
From the linked article.
“What we did was develop a model that could explain the current distribution of soil carbon across the globe as a function of climate, topography, geology and land use,” Dr Sanderman said.”
Why didn’t they say they just made it up? I am sure the funding would still be there.
There is a secret inter-dimensional tunnel and the carbon is sneaking over to Venus. Yeah, that’s it. Must be.
Who is this guy Dr Jonathan Sanderman? He works for Woods Hole Research Centre in Massachusetts. Woods Hole Research Centre? Sounds to me they needed the government funding or go broke.
Woods Hole Research Centre has relation to the reputed Woods Hole Oceanographic Institution and has nothing to do with “Research”, much less science.
It’s an activist group specializing in fear mongering. Hence their latest Nintendo-science garbage.
Even their name is a fraud.
I think, generally, this concept is correct. Some soils in some places around the world have lost Carbon since agriculture began.
But, on average, soils are now absorbing a net 2 billion tons of Carbon per year. That is what the Carbon Cylce numbers say.
Some was lost in the areas which were the early adopters of agriculture – the Fertile Crescent Iran, Iraq, Turkey, Lebanon, extending to Greece and Italy. Some more was lost in the US and Russia in the early 1900s and dustbowl years.
But that is over now. The soils are now adding back Carbon, partly as a result of the extra CO2 in the atmosphere and partly due to farming practices improving.
“World’s soils have lost 133 billion tonnes of carbon since the dawn of agriculture” Good!
[Why? You could put some content into your posts and try and add to what we know . . . mod]
“Carbon”–as in black soot, graphite, charcoal…what?
Where did it go?
Hopefully into the atmosphere. Hate to think of it bumbling around South Beach in miss matched bermuda shorts and hawaiian shirt, wearing black socks and sandals. Thats just disturbing.
‘Oxidation causes carbon reduction’…..
Reaction: “Wait a minute – That can’t be right!”
“Experts estimated”. I usually stop reading after these two words are used.
Oh, I don’t know, there is usually some comedy gold attached to those words.
Funny how no one sees the irony in this. The Romans ran a huge deforestation program, and so did the Chinese. Keep in mind, that agriculture was inefficient by modern standards, so they had to use extensive areas.
Over a couple of centuries, they easily released like 200-300Gt of CO2, equivalent to about 30ppm. Yet we do not see any antique CO2 peak.
Next to this, with the end of the ice age, the forestation of the northern hemisphere only started, going along with elevating(!!!) CO2 levels.
All that will not make a lot of sense, unless you accept the fact, that CO2 is very short lived. CO2 sinks take away about 2% of elevated CO2 levels every single year. Actually CO2 sinks scale perfectly with modern CO2 elevations, as my chart shows.
http://i736.photobucket.com/albums/xx10/Oliver25/Keeling%20vs.%20CO2%20sinks.png
With a half life period of only 35 years (which is consistent with the 2% figure), earlier civilizations simple could not enrich the atmosphere with CO2. And our modern civilization will not be able to read levels higher than ~520ppm with current output.
That reality of course, stands in strong contradiction to the claim, “our” CO2 emissions would stick around for centuries. Nothing could be further from the truth.