One has to wonder though, since CO2 residence time has been said to be anywhere from five year to hundreds, or even thousands of years, with no solid agreement yet, how they can be so sure of themselves?
From the University of Cambridge
4 degree rise will end vegetation ‘carbon sink’
Latest climate and biosphere modelling suggests that the length of time carbon remains in vegetation during the global carbon cycle – known as ‘residence time’ – is the key “uncertainty” in predicting how Earth’s terrestrial plant life – and consequently almost all life – will respond to higher CO2 levels and global warming, say researchers.
Carbon will spend increasingly less time in vegetation as the negative impacts of climate change take their toll through factors such as increased drought levels – with carbon rapidly released back into the atmosphere where it will continue to add to global warming.
Researchers say that extensive modelling shows a four degree temperature rise will be the threshold beyond which CO2 will start to increase more rapidly, as natural carbon ‘sinks’ of global vegetation become “saturated” and unable to sequester any more CO2 from the Earth’s atmosphere.
They call for a “change in research priorities” away from the broad-stroke production of plants and towards carbon ‘residence time’ – which is little understood – and the interaction of different kinds of vegetation in ecosystems such as carbon sinks.
Carbon sinks are natural systems that drain and store CO2 from the atmosphere, with vegetation providing many of the key sinks that help chemically balance the world – such as the Amazon rainforest and the vast, circumpolar Boreal forest.
As the world continues to warm, consequent events such as Boreal forest fires and mid-latitude droughts will release increasing amounts of carbon into the atmosphere – pushing temperatures ever higher.
Initially, higher atmospheric CO2 will encourage plant growth as more CO2 stimulates photosynthesis, say researchers. But the impact of a warmer world through drought will start to negate this natural balance until it reaches a saturation point.
The modelling shows that global warming of four degrees will result in Earth’s vegetation becoming “dominated” by negative impacts – such as ‘moisture stress’, when plant cells have too little water – on a global scale.
Carbon-filled vegetation ‘sinks’ will likely become saturated at this point, they say, flat-lining further absorption of atmospheric CO2. Without such major natural CO2 drains, atmospheric carbon will start to increase more rapidly – driving further climate change.
The researchers say that, in light of the new evidence, scientific focus must shift away from productivity outputs – the generation of biological material – and towards the “mechanistic levels” of vegetation function, such as how plant populations interact and how different types of photosyntheses will react to temperature escalation.
Particular attention needs to be paid to the varying rates of carbon ‘residence time’ across the spectrum of flora in major carbon sinks – and how this impacts the “carbon turnover”, they say.
The Cambridge research, led by Dr Andrew Friend from the University’s Department of Geography, is part of the ‘Inter-Sectoral Impact Model Intercomparison Project’ (ISI-MIP) – a unique community-driven effort to bring research on climate change impacts to a new level, with the first wave of research published today in a special issue of the journal Proceedings of the National Academy of Sciences.
“Global vegetation contains large carbon reserves that are vulnerable to climate change, and so will determine future atmospheric CO2,” said Friend, lead author of this paper. “The impacts of climate on vegetation will affect biodiversity and ecosystem status around the world.”
“This work pulls together all the latest understanding of climate change and its impacts on global vegetation – it really captures our understanding at the global level.”
The ISI-MIP team used seven global vegetation models, including Hybrid – the model that Friend has been honing for fifteen years – and the latest IPCC (Intergovernmental Panel on Climate Change) modelling. These were run exhaustively using supercomputers – including Cambridge’s own Darwin computer, which can easily accomplish overnight what would take a PC months – to create simulations of future scenarios:
“We use data to work out the mathematics of how the plant grows – how it photosynthesises, takes-up carbon and nitrogen, competes with other plants, and is affected by soil nutrients and water – and we do this for different vegetation types,” explained Friend.
“The whole of the land surface is understood in 2,500 km2 portions. We then input real climate data up to the present and look at what might happen every 30 minutes right up until 2099.”
While there are differences in the outcomes of some of the models, most concur that the amount of time carbon lingers in vegetation is the key issue, and that global warming of four degrees or more – currently predicted by the end of this century – marks the point at which carbon in vegetation reaches capacity.
“In heatwaves, ecosystems can emit more CO2 than they absorb from the atmosphere,” said Friend. “We saw this in the 2003 European heatwave when temperatures rose six degrees above average – and the amount of CO2 produced was sufficient to reverse the effect of four years of net ecosystem carbon sequestration.”
For Friend, this research should feed into policy: “To make policy you need to understand the impact of decisions.
“The idea here is to understand at what point the increase in global temperature starts to have serious effects across all the sectors, so that policy makers can weigh up impacts of allowing emissions to go above a certain level, and what mitigation strategies are necessary.”
The ISI-MIP team is coordinated by the Potsdam Institute for Climate Impact Research in Germany and the International Institute for Applied Systems Analysis in Austria, and involves two-dozen research groups from eight countries.
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jai Mitchell,
What you are missing is the effect of living things in the ocean waters you suppose to be in equilibrium according to Henry’s law. The ocean surface and atmosphere are not in equilibrium. Based on lots of measurements from instrumentation towed behind ships at several meters depth it was thought that atmospheric pCO2 was 7 u atm higher than the ocean, indicating saturation Takahashi et al 2012. Calleja_et al_GBC_2013 showed that there is an average pCO2 gradient of 14 u atm between 5m and the surface, 11 of which are in excess of temperature according to Henry’s law. These measurements were taken in the Mediterranean and North Atlantic and tropical Atlantic oceans, not where you expect upwelling to be pushing CO2 into the air.
The atmosphere Ocean interface is a magical place. More energy is cycled through this interface than the earth receives from the sun. An analogous nano carbon cycle also takes place across it, the magnitude of which we will never know until we quit building models that pretend it is in equilibrium and get our butts out there and measure it.
Re: My recent above posting: I am now estimating that atmospheric lifetime of CO2 beyond 300 PPMV is about 50 years in terms of halflife. The 14 years I got is atmospheric lifetime in terms of halflife of the portion of the CO2 that is past the level that is in equilibrium with the concentration of dissolved CO2 in the ocean surface waters. I expect this shorter figure to be similar to the bomb test results, since ocean surface water CO2 was not yet greatly elevated above that of ocean hundreds of meters down in the decade after the bomb tests.
CO2 retained in plants, 4 years?
So what is coal then?
These guys need to come and have a go at clearing my garden here in the tropics. If you leave it for a minute, I swear the grass grows an inch. If you leave for a month’s holiday, you need to borrow a neighbour’s tractor just to get to the house….
So where CO2 residence is concerned, the IPCC rejects the consensus?
“Its important to distinguish between the average residence time of a single molecule and the time needed to remove an accumulated stock of carbon.”
Yes, very important. The time needed to remove an accumulated stock of atmospheric CO2 is much shorter than the residence time of a single molecule. The atmosphere is in direct contact with the oceans after all. Any increase in the atmospheric pCO2 will drive it into the oceans very quickly. There’s nothing to stop it. Oceans contain much more than the atmosphere and they will hardly notice it.
but but… I thought all that carbon was going into the sea and acidfying it… 🙂 gigo
“The modelling shows that global warming of four degrees will result in Earth’s vegetation becoming “dominated” by negative impacts – such as ‘moisture stress’, when plant cells have too little water – on a global scale.”
Had they used a Ouija board for that, everyone would call them liars.
But somehow when you use a computer for the same purpose everyone suddenly assumes you’re an honest man.
I don’t doubt that their model shows what they say it shows. I just doubt that it is the only model one could make. An infinte number of models that all fit the past equally well, with wildly different outcomes in the future, are possible.
As always, this model HAS NO VALUE because the PREDICTIVE SKILL has not been demonstrated.
“The modelling shows …”
“Carbon-filled vegetation ‘sinks’ will likely become saturated …”
“The researchers say that, in light of the new evidence, scientific focus must shift …”
As usual, the PIK sleight of hand. Modelling does not SHOW anything; notice the “LIKELY”; the HAVE NO evidence; and look, there comes the demand; “focus MUST shift”.
Potsdam pseudoscientists and liars.
This whole discussion is slightly absurd. Why the focus on the biosphere alone ?
We do NOT even know which biological OR geophysical processes dominate globally in carbon sequestration and mobilization. This lack is a slight problem when trying to get some handle on what is going on, no ?
One thing I will point out is how likely it is that the amount of carbon sequestered in carbon-containing-sedimentary-rock-deposits is much larger than organic deposits. But we don’t have very good numbers for any of this.
This research seems to have been invented by geographers. Surely biologists/botanists know more about this sort of thing.
Max Roberts says:
They know more, but they are now under pressure to ration the release of their existing knowledge and to use externally imposed guidelines in the acquisition of new knowledge. I am sure (I sure hope) the Plant Sciences department next door will not publish anything as outrageous as the geographers at Clare just did, but I know the plant science folks are not indifferent to the outcome. They can now mention CO2, “environment” and “impacts” a dozen times per page in their grant applications. They use the funds granted this way to do real science (most of them do, most of the time, anyway), while Clare’s notoriety gets them the majority of student applications in Cambridge. Win-win. There is no disincentive in sticking one’s head out in a “progressive” sort of way. If anything goes wrong at Cambridge (unlikely), there are always careers to be made at the Grantham Institute.
Narrow range for Red Pine? Nonsense in one fashion, bizarrely stated in another.
Red Pine, (Pinus resinosa), also known as Norway Spruce grows anywhere in USDA zones 2 – 5.
Red/Norway pine is a very popular tree for planting and is easily available from local nurseries. Hard up for one? Easy, get one at Musser Forests.
Red pine is planted over a much greater geographical range now. Stands and landscape Norway pines are planted further south even in zones 6-7. It may not thrive as well, but t grows. So much for definite upper and lower limits.
The Forest Service’s page linked above describes how Red pine germinates best after a forest fire. The FS also mentions how the Red Pine migrated to survive previous climate changes.
Perhaps you are referring to the original Native distribution area? Though even that original distribution area is much larger than a 200 miles north south range.
Trees are far older than man and given the antics of the alarmists and MSM, perhaps wiser than many humans. Trees are definitely more adept at this climate stuff.
i thought that ”residence time” was the time that CO2 spent in the ATMOSPHERE not in plants or has Cambridge rewritten the GHG theory? Residence time in plants would depend on plant species for a start and probably hundreds of other inputs but not how much CO2 we put into the system since our proportion is but 3% of the total.
Seems this paper was written by Harry Potter.
The diagram in the article is bogus. The figures other than that of the IPCC are estimates of residence time (a.k.a. turnover time – the average length of time a molecule of CO2 remains in the atmosphere before being taken up by the oceans or terrestrial biosphere), the figure for the IPCC is an estimate of ADJUSTMENT time (the characteristic timescale on which atmospheric CO2 levels adapt to changes in sources or sinks). These are not the same thing at all, and whoever produced the diagram clearly didn’t bother to check their facts. The IPCC actually give an estimate of about 4 years for residence (turnover) time, which is completely in accordance with the other studies.
The residence (turnover) time depends on the volume of the fluxes out of the atmosphere, which are very large, so the residence time is short. The adjustment time depends on the difference between the fluxes into and out of the atmosphere, which is small (compared to anthropogenic emissions), which is why the adjustment time is much longer.
Please, in the interests of climate skeptics, stop promulgating this misrepresentation of the science. It is easily demonstrated to be incorrect, just look up “lifetime” in the glossary of the IPCC WG1 AR4 report (it appears on page 948).
So when co2 was 1,200ppm the world plunged into catastrophe? Nay, nay and thrice nay. What a load of modelling horse poop. Here is what I read above [my emphasis].
And they have the gonads to mention the IPCC modelling.
Here are some real observations of the past. Check out the temperatures.
Co2 is plant fertilizer even at 800ppm and more. We have such a long way to go and I very much doubt we will ever hit 800ppm, but I hope we do. Enter the projectionists: If China and India’s co2 output follows their present trajectory………blah, blah. Would you care to say the same about the USA? Things change!
Good graphic! This 4C threat, like the 2C threat, is presented as a major disturbance to the climate system. A system that copes every year with about a 4C variation in mean temperature as it orbits round the sun.
Dikran, the adjustment time is shorter than the residence time. When there is a partial pressure gradient beteween the atmosphere and the oceans, what’s there to stop the CO2 flux into oceans?
Bill Illis says:
December 16, 2013 at 1:23 pm
Temperatures were about 3.0C to 4.0C higher in the Miocene from about 15 Mya to 20 Mya. The Carbon cycle does not appear to have been any different since CO2 was about 250 ppm to 280 ppm in the period (although there a few random estimates at 400 ppm but these are just a few random estimates amongst hundreds of others in the 250 to 280 range).
On the contrary we had the evolution of C4 plants to combat such a change.
Edim, the figure given in the article above is clearly incorrect. The IPCC say that residence time is about 4 years, not 50-200 years, anyone who doesn’t believe me can look it up for themselves in the IPCC report, I have given the page number to make it as easy as I can. Unlike Ferdinand, I do not have infinite patience to explain these misunderstandings again and again. I wrote a journal paper on this topic in the hopes it might go somewhere towards ending the discussion of this canard on climate blogs, which only serves to discredit the skeptic community by its repetition. You can find the paper here:
http://pubs.acs.org/doi/abs/10.1021/ef200914u
Gavin C. Cawley, On the Atmospheric Residence Time of Anthropogenically Sourced Carbon Dioxide, Energy Fuels, 2011, 25 (11), pp 5503–5513
Abtract
A recent paper by Essenhigh (Essenhigh, R. H. Energy Fuels 2009, 23, 2773−2784) (hereafter ES09) concludes that the relatively short residence time of CO2 in the atmosphere (5–15 years) establishes that the long-term (≈100 year) rise in atmospheric concentration is not due to anthropogenic emissions but is instead caused by an environmental response to rising atmospheric temperature, which is attributed in ES09 to “other natural factors”. Clearly, if true, the economic and political significance of that conclusion would be self-evident and indeed most welcome. Unfortunately, however, the conclusion is false; it is straightforward to show, with considerable certainty, that the natural environment has acted as a net carbon sink throughout the industrial era, taking in significantly more carbon than it has emitted, and therefore, the observed rise in atmospheric CO2 cannot be a natural phenomenon. The carbon cycle includes exchange fluxes that constantly redistribute vast quantities of CO2 each year between the atmospheric, oceanic, and terrestrial reservoirs. As a result, the residence time, which depends upon the total volume of these fluxes, is short. However, the rate at which atmospheric concentrations rise or fall depends upon the net difference between fluxes into and out of the atmosphere, rather than their total volume, and therefore, the long-term rise is essentially independent of the residence time. The aim of this paper is to provide an accessible explanation of why the short residence time of CO2 in the atmosphere is completely consistent with the generally accepted anthropogenic origin of the observed post-industrial rise in atmospheric concentration. Furthermore, we demonstrate that the one-box model of the carbon cycle used in ES09 directly gives rise to (i) a short residence time of ≈4 years, (ii) a long adjustment time of ≈74 years, (iii) a constant airborne fraction, of ≈58%, in response to exponential growth in anthropogenic emissions, and (iv) a very low value for the expected proportion of anthropogenic CO2 in the atmosphere. This is achieved without environmental uptake ever falling below environmental emissions and, hence, is consistent with the generally accepted anthropogenic origin of the post-industrial increase in atmospheric carbon dioxide.
The adjustment time cannot be shorter than the residence time, if you think that is the case, you do not understand the meanings of these terms. The residence time depends on the rate CO2 is taken out of the atmosphere. However the rate at which an excess of CO2 is removed from the atmosphere also depends on the rate at which it is being added by the natural environment, which is why adjustment time is inevitably longer.
The graphic lists the graph’s source as Lawrence Solomon’s “The Deniers,” but perhaps it would help the readership to know (1) whether the red bar was in the original and (2) how that particular graphic was chosen to accompany the post without explanation of its precise relevance.
Maybe there’s something I’m missing, but I’m inclined to share vikranmarsupial’s reservations about its inclusion.
Dikran, when you add CO2 to the atmosphere, you increase the pCO2 in the atmosphere and therefore create a gradient in pCO2 (atmosphere/oceans). What is the mechanism that prevents the CO2 influx into oceans? The oceans can hardly notice the increase, since they contain MUCH more.
I will repeat again – the adjustment time must be shorter than the residence time. It might take a long time to remove a molecule (it has to be present at the exchange interface) , but how can it take long time to equalize partial pressures? It makes no sense.
Edim, do you agree that the figure is incorrect and that the actual residence (turnover) time given in the IPCC reports is about four years? Yes or no.
Dikran, I don’t know – I only know that there is so much confusion. The consensus scientists themselves are not precise at all and mix the terms.
My point is that the adjustment time is even shorter than the atmospheric ‘life time’ of an individual molecule, simply because the atmosphere is in direct contact with the oceans, while an individual molecule is not.
dikranmarsupia and Jai Mitchel
That the dynamic equilibrium of the biosphere(Ie time to equilibrium after a pertubation) is very long is counter to evidence along many lines.
1. Each year 1/2 the excess CO2 is taken up by something.
2. The ocean cannot be in equilibrium with a rising atmospheric partial pressure of CO2 (Only can be in equilibrium with a constant partial pressure CO2)
3. The Ocean does not exchange one for one, even with a constant partial pressure of CO2, some of the CO2 is removed to the lower ocean, or consumed by the plant-life, bacteria life in the ocean, losses if you like.
4. Observationally plant productivity varies quickly as CO2 partial pressure rises, not slowly. One would expect photosynthesis, vegetation productivity, vegetation density, and vegetation range to adapt to CO2 changes within a few years.
Some of the issues.
It has already been mentioned that warmer climates reduce drought.
Desert areas are not generally determined by temperature but rather by continental positions relative to the dominant circulations.
Temperature rise is known to be biassed to the minimums, for example the minimum temperatures are reduced. Moving from polar regions to the equator we generally see less extreme climates, with the temperature ranges narrowing to 10 degrees near the equator. Maximum temperatures at any given latitude (where the max is significantly above freezing) are likely to fall with global warming while minimums rise (more than the maxes fall). This known pattern (due to water evaporation) is counter to the assertion that droughts will emerge from warming.
As temperatures rise vegetation patterns would move northward, (in the Northern Hemisphere) Vegetation wont die out, it will move based on the new distribution of rainfall, and the relevant circulations controlling rainfall. As Vegetation moves further northward where the largest land masses are I would expect an increased sinking effect due to higher vegetation density and extended growth range of vegetation (in the far north). Can’t say much for the south because there aren’t many land-masses in the right place for range expansion
All of this ignores the fact that raising the temperature by 4 Degrees would imply an energy absorption by CO2 to be increased by about 12% from 85% absorption to 97% absorption (assuming that all the 33 degree rise above blackbody of the atmosphere has to do with GHGs (which it is not)) at which point the energy absorbed by CO2 would be 97% of incident. This requires many doublings of CO2 to achieve. – IE 4 degrees of warming is practically impossible to achieve, if I recall correctly by the time CO2 is dense enough to cause 4 degrees of warming, combustion will be impossible because O2 levels will be too low to support combustion.
Edim, says “Dikran, I don’t know”
O.K., so you can’t be bothered to check whether basic information is correct or not, I have to say that is not what I would call skepticism, but perhaps it explains how such canards manage to survive in climate discussions on blogs.
I have already explained why adjustment time cannot possibly be less than residence time, but you have ignored that explanation, and just repeated yourself, so there is little point in me continuing the disucssion.