by Adam Jones – click to order a photo or poster
I’ve covered this before, such as when NASA posted satellite data showing that the biosphere is booming thanks to CO2 fertilization. This new study from Goethe University in Frankfurt, Germany suggests that the Umbrella Thorn Acacia trees will make a comeback.
Tree trumps grass to rule the savannas
A new study published today in “Nature” by authors from the Biodiversity and Climate Research Centre and the Goethe University Frankfurt suggests that large parts of Africa’s savannas may well be forests by 2100. The study suggests that fertilization by atmospheric carbon dioxide is forcing increases in tree cover throughout Africa. A switch from savanna to forest occurs once a critical threshold of CO2 concentration is exceeded, yet each site has its own critical threshold. The implication is that each savanna will switch at different points in time, thereby reducing the risk that a synchronous shock to the earth system will emanate from savannas.
Tropical grasslands, savannas and forests, areas the authors call the savanna complex, are expected to respond sensitively to climate and atmospheric changes. This is because the main players, grasses and trees, differ fundamentally in their response to temperature, carbon dioxide supply and fire and are in an unrelenting struggle for the dominance of the savanna complex. The outcome of this struggle determines whether vast portions of the globe’s tropical and sub-tropical regions are covered with grasslands, savannas or forests. In the past such shifts in dominance have played out in slow motion, but the current wave of atmospheric changes has accelerated the potential rate of change.
Experimental studies have generally shown that plants do not show a large response to CO2 fertilization. “However, most of these studies were conducted in northern ecosystems or on commercially important species” explains Steven Higgins, lead author of the study from the Biodiodversity and Climate Reseach Centre and Goethe-University. “In fact, only one experimental study has investigated how savanna plants will respond to changing CO2 concentrations and this study showed that savanna trees were essentially CO2 starved under pre-industrial CO2 concentrations, and that their growth really starts taking off at the CO2 concentrations we are currently experiencing.“
The vegetation shifts that the Higgins and Scheiter study projects are an example of what some theorists call catastrophic regime shifts. Such catastrophic regime shifts can be triggered by small changes in the factors that regulate the system. These small changes set up a cascade of events that reinforce each other causing the system to change more and more rapidly. The study demonstrated that the savanna complex showed symptoms of catastrophic regime shifts. “The potential for regime shifts in a vegetation formation that covers such vast areas is what is making earth system scientists turn their attention to savannas” comments Higgins.
Knowing when such regime shifts will occur is critical for anticipating change. This study discovered that locations where the temperature rise associated with climate change occurs rapidly, for example in the center of southern Africa, are projected to switch later to forest as the high rate of temperature increase allows the savanna grasses to remain competitive for longer in the face of rising atmospheric CO2 concentration. This means that even though a single location may experience its catastrophic regime shift, the vegetation change when averaged over a region will be smoother. Such gradual transitions in regional vegetation patterns will reduce the potential for shocks to the earth system. “While this may seem reassuring, we have to bear in mind that these changes are still rapid when viewed on geological time scales”, says Higgins.
The practical implications of the study are far reaching. For example, the study identified a belt that spans northern central Africa where fire suppression would encourage savannas to transition to forests. “So if you wanted to sequester carbon as part of a carbon mitigation action, this is where you should do it” explained Higgins “with the caveat that where this will work is shifting as atmospheric conditions change.” A worrying implication is that the grasslands and open savannas of Africa, areas with unique floras and faunas, are set to be replaced by closed savannas or forests. Hence it appears that atmospheric change represents a major threat to systems that are already threatened by over-grazing, plantation forestry and crop production.
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Paper:
Steven I. Higgins and Simon Scheiter (2012). Atmospheric CO2 forces abrupt vegetation shifts locally, but not global. Nature, DOI: 10.1038/nature11238
Smokey says:
July 4, 2012 at 8:26 am
Carrick says,
“If you mean by evidence that it has to be directly observed, that’s just silly.”
Yes, that is exactly what I mean: show me evidence. Without evidence, you are simply speculating based on your own personal belief.
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I refer to:
Carrick says:
July 3, 2012 at 10:00 pm
“….That CO2 affects climate is really not in doubt…………..
Some people choose to define the problem of “verification of the impact of CO2 on climate” to be one that is impossible to ever demonstrate. That serves no practical value and is just pure sophism, from my point of view.” ALL CORRECT.
AND…
If I got your point correctly:
1.To debate the notion that CO2 as a gas traps outgoing infrared radiation, hence leading to a greenhouse effect, is a refutation of basic physics. ( You said: “I am not disputing physics”).
2.The notion of a CO2 influence on earth’s climate, continually tested and proven through nearly a century of primary research.
3.There are several papers on CO2 being harmful to the marine biosphere the largest source of biomass on the planet via ocean acidification. The potential inhibition of calcifying organisms can in no way, form be characterized as “beneficial to the biosphere”.
4. If you do not believe that ocean acidification is a real phenomenon, then you have to reject acid rain as a real phenomenon. Unfortunately, acid rain has already demonstrably happened.
5.Personally, I incredibly not worried about CO2 in the atmosphere imminently leading to an Armageddon Scenario. But that does not mean we should not research the issue at hand, the better to understand any future potential complications at play.
Smokey says:
July 4, 2012 at 8:26 am
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Carbon dioxide is produced under certain conditions.
In practice, sources of carbon dioxide, including that resulting from natural or human factors, they do not produce pure carbon dioxide, for example, forest fires, volcanic activities and incomplete combustion of fossil fuels.
Carbon dioxide is not a pollutant. But its production sometimes is associated with soot and aerosols.
However, the formation of soot or Black Carbon (BC) is widely influential in climate change.
Black Carbon gives a short-term, but powerful boost to heating the planet. It is a “short-term” climate Forcer, acting for a few days in the atmosphere and a few months on snow and ice.
So, reductions in BC have immediate, but not long-term effects on global warming. Each CO2 molecule continues to block heat loss from the Earth for the 100+ years that it stays in the atmosphere. That is why CO2 is known as the Biggest Control Knob” for the climate.
acckki says:
“Each CO2 molecule continues to block heat loss from the Earth for the 100+ years that it stays in the atmosphere.”
Wrong. And there is zero evidence that CO2 is a “control knob” for the climate. You get called on it when you post that nonsense here.
We are past the point where additional CO2 matters.
Smokey says:
July 5, 2012 at 4:08 am
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You’ve provided a diagram for “residence time of atmospheric CO2”. Here you can see 37 different states.
Accordingly, the minimum and maximum residence time of atmospheric CO2 is:
1. According to the IPCC assessment in 2007, 100 years (the maximum possible by now),
2. Machta estimated in 1972, about 2 years (the minimum possible by now),
Assume now that the resources for all 37 theories were identical;
The result is:
1. there is no consensus about the residence time of atmospheric CO2;
2. CO2 is a longer-lived greenhouse gas;
So you made your reference WRONG to show that the residence time of Atmospheric CO2 is less than (100+). Thank you.
But this (100+) was not your main problem with my comments. You asked for “evidence”. Hopefully you got the “evidence” you were looking for.
Carrick: We demonstrate that CO2 absorbs infrared radiation, thereby impeding outward flow of heat energy from the Earth, well that’s a demonstration that CO2 affects climate. How it affects climate is different from the simple, obvious fact that it does affect climate.
CO2 is a trace gas and as such via its physical properties can only affect the environment in proportion to its mass. This is basis physical science which btw Al Gore failed. You have made the same fundamental mistake (logical fallacy) all AGW proponents make, the use of the inane to claim an extreme. It is a well demonstrated fact H2O vapor is far more of a greenhouse gas than CO2 in ADDITION to its overwhelming quantities in proportion to CO2. And NO, CO2 does not alter the H2O quantities in the atmosphere which is a central thesis of AGW.
The IPCC deliberately did not include H2O in the global warming index chart of gases by wrongfully and deceitfully claiming humidity, i.e. water vapor does not change over time and therefore is irrelevant to consider which I call the “all things being equal fallacy”. AGWers want to have it both ways, first they claim water vapor doesn’t change and then they claim CO2 levels change humidity levels causing droughts and floods. AGW is specious double think or cognitive dissonance masquerading as logical thought.
Then you mix apples with oranges (another logical fallacy) by including CO2 benefits to plant growth to prove CO2 affects the global atmosphere, i.e. climate. Wrong, CO2 levels affect plant growth and only indirectly affect local geographical weather patterns BUT NOT on a global scale. But by doing this you have just tripped up the entire AGW narrative by admitting that land use (the degree of vegetation types versus non vegetation per unit area) affects the “temperature and rainfall” of a region. Hence you now have undermined the argument for the dismissing of Southern Hemisphere’s lack of upward trend in temp (because it is water dominated) and that ALL of the trend is strictly in the Northern Hemisphere, being a land dominated hemisphere. A land dominated hemisphere is subject to land use changes. Ironically, this study actually undermines AGW. The bulk of ALL temperature increases are in Europe and Asia where forests were cut down in favor of farming and grazing in addition to the UHI of cities from population change. The bottom line is land use is the main causal factor in temperature trends and CO2 influences are indirect or secondary by favoring and disfavoring plant species in addition to countless other indirect 2nd and 3rd order influences such as population, precip, fauna, jet stream, insolation, etc, etc, etc…
Smokey,
1. I refer to my above comment:
“The contribution of carbon dioxide to the warming is expected because of the “greenhouse” effect and THE MAIN QUESTION IS HOW LARGE IT IS…”.
2. I refer to your comments:
2.1. “Maybe I wasn’t clear enough. I am not disputing physics. I am not disputing that the rise in CO2 is greening the planet; it is. I am disputing the central tenet of runaway global warming believers: that the rise in CO2 causes quantifiable effects on the planet’s ‘climate’, by which they mean global temperature.”
2.2. “We are PAST THE POINT where additional CO2 matters.”
You are trying to recall the fact that increasing carbon dioxide in the atmosphere never coincides with increasing temperature.
It can be concluded from the above discussion and your references that, firstly, the impact of atmospheric carbon dioxide on temperature is not ruled out, and secondly, this effect is negligible.
I would be grateful to have your full references from The University of Chicago in this regard.
(your complete reference resulted to: http://c3headlines.typepad.com/.a/6a010536b58035970c0115707ce438970b-pi)
thanks in advance
acckkii says:
“…firstly, the impact of atmospheric carbon dioxide on temperature is not ruled out, and secondly, this effect is negligible.”
I agree with that statement.
As for the references, I copied and posted the link, but it is not my creation. But I believe it to be accurate, as I have seen similar charts elsewhere. If you go here you will see an email address at the top. I’m too old to do homework, except for myself.
Smokey,
God bless you.
I’m 62.
thanks
acckkii says:
July 3, 2012 at 9:51 am
“Today, one should not overlook that the wild fires in Colorado is acknowledged to relate to the increased carbon dioxide in the atmosphere.”
Yup, like the ice cores, CO2 upticks occur because of the temperature – a forest fire can reach 1200C+ and generate a lot of CO2.
Acckkii, also, your thing about rising CO2 not contributing much to plant growth. Get a grip. We are talking about creatures made mainly out of C – where do you think it came from? Note also numerous papers (one recently here on a CO2 experiment with rice) – greens have attacked the “fertilizing” effect of CO2 because it is so darn obvious. They want it to stay in the atmosphere to make more heat. The pesky stuff even disappears into the ocean so the greenies have raised the spectre of ocean acidification. They are trying to cut CO2 off at the pass – but don’t you fall for it – your too old for that at 62, even though you are a spring chicken compared to me.
Gary Pearse says:
July 7, 2012 at 12:30 pm
“….even though you are a spring chicken compared to me.”
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1- CO2 is good for plants, don’t think about that any more,
2. Smokey says:
July 5, 2012 at 1:31 pm
acckkii says:
“…firstly, the impact of atmospheric carbon dioxide on temperature is not ruled out, and secondly, this effect is negligible.”
I agree with that statement.
Regards,