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Explainer: how much carbon can the world’s forests absorb?

You are walking through the bush when you see an enormous tree trunk, tens of metres long, lying across the forest floor. Imagine you and several dozen friends lifting it by hand. Now you’ve literally…

If deforestation is cut down, the world’s forests could act as a large net sink for carbon emissions. Flickr/sobriquet.net

You are walking through the bush when you see an enormous tree trunk, tens of metres long, lying across the forest floor. Imagine you and several dozen friends lifting it by hand. Now you’ve literally grasped the significance of trees and forests when it comes to carbon sequestration - trees are heavy, and carbon accounts for almost half their dry weight, or biomass.

The world’s forests are a net carbon “sink”. Each year they remove more carbon from the atmosphere by photosynthesis than they return via their own respiration, decomposition of dead roots, trunks and leaves, and by forest fires.

That is how the growth and re-growth of forests around the world has slowed climate change in the past century. It has been estimated that between one-third and one-fourth of the total carbon dioxide (CO2) emissions from burning coal, gas and petrol has been turned into wood and other plant parts through this process. Without that incredible ecosystem service, climate change would be much more extreme today than it already is.

Despite advances in satellite remote sensing and ground inventories, our estimate of the area covered by forests globally is surprisingly shaky. We are unsure how much the trunks of all those trees weigh, nor can we know for certain the weight of their roots. It is even harder to figure out how much the total global forest biomass grows from one year to the next - a key figure that tells us how much of our annual CO2 pollution has been scrubbed out of the air by forests.

Forest ecologists like a challenge however, and there have been several attempts at estimating the forest carbon “sink”. Perhaps the most internationally comprehensive approach was an assessment of forest carbon stocks and fluxes across the globe between 1990 and 2007. They assessed the carbon content of live biomass, dead wood, litter, oil organic matter and harvested wood products in tropical, temperate and boreal forests, and examined how these stocks changed over roughly two decades.

According to this analysis, intact forests and those re-growing after disturbance (like harvesting or windthrow) sequestered around 4 billion tonnes of carbon per year over the measurement period — equivalent to almost 60% of emissions from fossil fuel burning and cement production combined.

This news is not as good as it seems. During the time measured, tropical deforestation resulted in the release of almost 3 billion tonnes per year. Thus, globally, the net forest carbon sink amounted to just 1.1 billion tonnes per year or one-seventh of average emissions from fossil fuel burning and cement production over the period measured.

These numbers suggest that forests, and tropical forests in particular, could play a key role in slowing the rise of atmospheric CO2 in the decades to come.

In the tropics, growth and re-growth of forests generated a colossal carbon sink of 2.8 billion tonnes of carbon per year. This largely, but not entirely, counterbalanced the equally colossal carbon emissions associated with deforestation of other tropical forests. As a result, the tropics served as a relatively small net source of carbon to the atmosphere since 1990.

If deforestation continues unabated, and droughts and forest fires become more common, as is expected, then tropical forests could become a large net source of carbon to the atmosphere, heating up the pace of climate change. Disturbances to temperate and boreal forests from climate change-induced droughts, wildfires and windstorms could make the situation even worse.

Conversely, if deforestation was to slow in comparison to continued growth of recovering and intact forests, tropical forests could serve as a large net sink of carbon in the future and make the United Nation’s Reducing Emissions from Deforestation and Forest Degradation (REDD) programme a meaningful contributor to offsetting emissions.

Our best estimates of global forest carbon sinks and sources demonstrate the ongoing importance of forests to the global carbon cycle. Unfortunately, however, they do not provide a road map to the future.

If forest “scrubbing of CO2” declines while release of CO2 remains stable or grows, the “braking” effect of the world’s forests on the pace of climate change will grow weaker, perhaps disappearing entirely. That would be truly bad news for the global climate and those who depend on it.

And unfortunately, that is not just a lot of hot air.

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66 Comments sorted by

  1. John Newlands

    tree changer

    I think there are several problems in relying upon forests as a carbon sink. One is novel interpretation of the supposed rules. For example Norway paid Bolivia to preserve a forest under the REDD scheme so the Bolivians raised the adjoining forest instead. In Australia forestry interests claim that durable uses for timber (like floorboards) are a carbon sink and the forest regrowth accelerates the cycle. They omit to mention that many logs unsuited to sawing go to the chipper to make shortlived…

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    1. Mark Poynter

      Forester

      In reply to John Newlands

      John

      I agree with some of what you say, but not all.

      Yes, paper products can have a relatively short service life, but some of it has a lengthy life eg. books. Also, once the service life ends, a substantial proportion (about 50% I think) is recycled, thereby prolonging the carbon storage. Also, a substantial proportion is not ultimately burnt, but ends up in land fill where research has shown it can store carbon for at least another 20 - 30 years, and could be used to produce renewable energy…

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    2. Ben Moore

      Lecturer, Hawkesbury Institute for the Environment, University of Western Sydney

      In reply to John Newlands

      John,
      Carbon credit schemes are designed as an incentive to encourage the protection and development of carbon sinks. If sequestration in these sinks subsequently suffers a setback, for reasons presumably beyond anyone’s control, why should carbon credits be revoked? This would only serve to reduce the incentive to plant trees and punish an innocent party. The important consideration should be whether burnt plantations or forests continue to be managed as carbon sinks. I.e. are they allowed to…

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    3. John Newlands

      tree changer

      In reply to Ben Moore

      I suggest forestry carbon sinks could become a form of moral hazard whereby we desperately want them to 'succeed' so we lull ourselves into thinking they are better than are. As physicist Richard Feynman said we can fool ourselves but not (Mother) Nature. I have serious reservations about the carbon credits accorded to indigenous burning of the NT savannah. That could be the thin end of the wedge.

      If just one carbon credit got revoked because a forest later burned down. it would be a major…

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    4. James Hill

      Industrial Designer

      In reply to Mark Poynter

      Yes, historically and before the expansion of the Grid, milk factories on the NSW North Coast generated their won electricty using steam turbines,
      I hitched a lift from a truck driver who was going to a nearby State forest to collect sawdust, from locall milling, to fire these still existent steam powered generating plants.
      Things, however, might have changed in the last two decades.

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    5. James Hill

      Industrial Designer

      In reply to Ben Moore

      Even in Medieval England under the Norman Conquest, a totalitarian regime if ever there was one, ( undertaken under a Papal banner to reinforce the point) forest wardens were appointed to make sure that the forests and the wild life in these original "Conservation Parks" were not destroyed by fire.
      In Australia, supposedly "heir" to this tradition of forest wardens, the conservation parks are held to be "wilderness" and without adequate management and protection, regularly and disastrously burn down.
      Much CO2, including that from the incinerated wildlife, is lost to the atmosphere.
      No mention need be made, one hopes, of the very serious loss of human life that also follows the "wilderness" embargo on active management and prevention of serious, destructive conflagrations.
      So there must be a sensible incentive to prevent the holocausts caused by the "wilderness" mind set, which even the backward English medievalists rejected in favour of intervention and prevention.

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    6. David Arthur

      resistance gnome

      In reply to John Newlands

      Thanks for that, John.

      There's one point I'd like to pick up, and that's the idea that forest growth can somehow excuse a bit of coal burning. My understanding is that this notion is, at best, wishful thinking.

      You see, to avoid runaway greenhouse warming, we need an atmosphere with no more than 350 ppm CO2 (no less than 250 ppm CO2 also, lest the world revert to Ice Age conditions).

      Because atmospheric CO2 is already ~400 ppm, this means we MUST achieve two distinct goals.

      1) totally cease all FOSSIL fuel use ie stop adding to the problem
      2) achieve as much reafforestation as possible, to try to get atmospheric CO2 back down to no more than 350 ppm.

      There's a third thing we can do as well, which is to hope that these two measures are sufficient. Don't allow any mealy-mouthed conman sell you the notion that we can do the reafforestation instead of totally ceasing fossil fuel use. We must do both, not just do one as a substitute for the other.

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    7. David Arthur

      resistance gnome

      In reply to Mark Poynter

      Mark, fair comment about biomass energy, except that where biomass energy is simply obtained by combustion, a huge proportion of nutrients that ideally should be recycled to the plantation also go up in the smoke.

      The Good News is, the biotech people are working on ways of digesting cellulose and possibly also transforming lignin to simpler fuels, thus greatly decreasing nutrient loss.

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    8. Richard H. Stafursky

      logged in via Facebook

      In reply to John Newlands

      John, yes, who really conserves? In the US I recently witnessed a land trust conservation purchase of about 120 acres of Massachusetts forests. The local newspaper said that the land trust bought the forest and that the seller of the acres was a good conservationist, because he sold it to the land trust. The truth was that the seller tried for many years to make the forest mountain into an expensive housing development and even installed a road to the top of the mountain with lights and utilities…

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    9. Mark Poynter

      Forester

      In reply to David Arthur

      David

      The reality is that the bush will eventually burn anyway, and so burning forest and sawmill waste for biomass is arguably little different to what naturally happens in a fire-prone landscape.

      In addition, my understanding is that biomass would be produced only from woody waste that is either currently just burnt to dispose of it, or used for some other low value product such as wood chips. Most of the forest nutrients are contained in foliage and this would not be used for biomass…

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    10. David Arthur

      resistance gnome

      In reply to Mark Poynter

      "... the bush will eventually burn anyway, and so burning forest and sawmill waste for biomass is arguably little different to what naturally happens in a fire-prone landscape."

      Bush may eventually burn anyway, but at a much lower average rate of cycling through fixing-burning than takes place in managed forests.

      Get thinking big about this, Mark. IF the forestry industry is able to do as I propose, ie recover biofuels from forestry while recovering nutrients to enhance regrowth, as well as greatly improve efficiency of energy recovery from forestry waste, then there would be a strong case to be made for granting industry access to a much larger proportion of the national forest.

      Not only that, but with nutrient recovery, it may even be possible to expand the forested area of Australia, thus achieving greater carbon drawdown than set out in Peter Reich's article.

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    11. Greg North

      Retired Engineer

      In reply to James Hill

      Australia is just a tad different to the UK James, not just in size and population density but climate, geology, topography and flora all having a great impact.

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    12. Greg North

      Retired Engineer

      In reply to John Newlands

      Forests do certainly have to be rigorously managed John if they are to be an effective carbon sink and harvesting ought to be part of the management to on one hand enhance ability to do burn offs and so reduce risk of wild fires and also to provide access so as to more readily combat fires that do break out from lightening strikes.

      I also remember reading years ago something about trees absorbing more CO2 during peak growth times and so if it can be accurately determined for particular species…

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    13. James Hill

      Industrial Designer

      In reply to Greg North

      The argument depends upon the similarities, surely, there are droughts and there are forestfires in the Northern Hemisphere and the population densities in the medieval era were similar to those in Australia.
      So over to you, Greg.
      The difference with Australia being the neglect of that shared heritage as embodied by the Terra Nullius style "wilderness" mind set, of the white, middle class, suburban elite.

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    14. Greg North

      Retired Engineer

      In reply to James Hill

      " The argument depends upon the similarities, "
      Enough said then James and you just might want to review the basis of the argument.

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    15. greg fullmoon

      being and doing

      In reply to Mark Poynter

      methane capture from landfill is about 50% this is then burnt as a fuel releasing further Carbon (admitted not a lot) to atmosphere..

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  2. Peter Evans

    Retired

    It would be interesting and useful to see this issue put as an expression of the amount of carbon storage we can achieve through increasing forest growth. One way to put that might be to ask "Who many trees do we need to plant, after taking into account losses through land clearing and forestry activity, to achieve our emissions reduction target by 2020?". This would go a long way to showing whether it is achievable or not.

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  3. James Hill

    Industrial Designer

    Apparently 15,000 years ago a drought began in Australia, following a very much wetter period, "Riverine Response to Altered Hydrologic Regimen".
    In the Australian tropics, this drought, which lasted ten thousand years, appears to have favoured fire dependent eucalypt forests with the original rainforest of the former wet period surviving in isolated elevations protected from encroaching fire.
    In the last five thousand years a wet environment has appeared that, if the above article is to be given…

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    1. David Arthur

      resistance gnome

      In reply to James Hill

      "Apparently 15,000 years ago a drought began in Australia, following a very much wetter period, "Riverine Response to Altered Hydrologic Regimen"." Would you be so good as to provide a reference?

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    2. James Hill

      Industrial Designer

      In reply to David Arthur

      "Riverine Response to Altered Hydrologic Regimen".
      Somewhat lacking in comprehension there David?
      An academic paper.
      Happy Searching!
      Clue, something to do with the study of rivers.
      Are you deficient in critical intellectual capacity?
      In which case don't bother.
      You, and your ilk, will have trouble finding someone to spoon feed you your understanding, and you'd probably spit it out any way.
      Want more information?
      Why would I want to waste my effort on you, when you cannot make any effort yourself?

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    3. David Arthur

      resistance gnome

      In reply to James Hill

      Thanks James. I copied the title exactly as you had entered it into a search engine, and it didn't turn up the paper within the first couple of pages of results. If you had reproduced the title correctly, it would have been there. Please give up on the gratuitous insults, and just supply an author name.

      The reason is, wqant to read this paper to see if it has anything to say on whether Australia's dry climate was caused by Aboriginal burning practices changing forest structure, or whether there was an ongoing drought during the entire period from the Last Glacial Maximum through the warming period to the Holocene Epoch; for a dry period to persist through that entire transition would be quite unusual.

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    4. James Hill

      Industrial Designer

      In reply to David Arthur

      Pardon my abusive reply, I read that report in a specialist professional library almost forty years ago and guess what I cannot remember the author's name, so the next thing for me to do is to pretend it does not exist?'
      I did get confirmation of its existence in a conversation with a science undergraduate, studying Hydrology( by the text book he was studying while waiting for a train), about twelve years ago, who said it was a classic study.
      So forgive me if, absent its prominence on the internet…

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    5. Greg North

      Retired Engineer

      In reply to David Arthur

      You will find some general references to climatic conditions and growth changes by reading up on Indigenous history, one article being - http://en.wikipedia.org/wiki/History_of_Indigenous_Australians

      It seems that research would show a dryness or long term drought occurred initially as a result of an Ice Age during which sea levels, rainfall and CO2 levels were all quite considerably lower and thus a lot of rain forest died off.

      I would think that research ought to happen into what kind of…

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    6. David Arthur

      resistance gnome

      In reply to Greg North

      Thanks Greg. My understanding is that it is quite plausible that Ice Ages are times of drier conditions, certainly in temperate latitudes such as the Murray-Darling and the Nullarbor Plain.

      I am less certain of the extent to which drier conditions would have pertained in tropical Australia.

      What struck me about James Hill's reference to an old paper setting out evidence of an extended dry period affecting the tropics from 15 millenia ago (the latter part of the last glacial period ("Ice Age" in the popular parlance) to 5 millenia ago (well into the interglacial Holocene Epoch) are firstly, that this drought is purported to have persisted through the entire transition from glacial (cold to interglacial (warm) period. It is this point, in particular, about which I was surprised.

      I shall email paleoclimatologist, Dr Andrew Glikson, if he can enlighten us on this issue.

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    7. David Arthur

      resistance gnome

      In reply to David Arthur

      Dr Glikson refers us to "Late Pleistocene and Holocene climate of SE Australia reconstructed from dust and river loads deposited offshore the River Murray Mouth", Earth and Planetary Science Letters 255 (2007) 257–272, (http://people.rses.anu.edu.au/dedeckker_p/pubs/29.pdf), in which Gingele, De Deckker & Norman published their analysis of a sediment drill core obtained offshore from the Murray River mouth.

      The core was interpreted as showing that the period from 7500 to 5000 years ago was, indeed, quite dry. However, particularly wet periods were recorded from 13,500 to 11,500 years ago, and again from 9,500 to 7,500 years ago - all results consistent with other paleoclimate records from SE Australia (see article references).

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  4. James Hill

    Industrial Designer

    India, originally, before the arrival of the nomadic "Cattle" people, was covered by rainforest.
    The cattle, whose ancestors still live in the Indonesian rainforests, browse on young trees, and eventually vast areas of rainforest were grazed away.
    Try a time period of about six thousand years.
    A Doctor Venkat, was able to show, recently, that if cattle were excluded from a certain area, and rainforest and other trees replanted, not only would the forests grow but that treeroots growing far down…

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    1. John Nicol

      logged in via email @bigpond.com

      In reply to James Hill

      No doubt James you have studied carefully the land used in the far North for grazing cattle. However, I do not think the suggestion that any one who may not share your ideas "are somehow devoid of the critical application of intelligence."

      It does appear that many environmentalists are not interested in including human beings and their activities among the list of phenomena representing biodiversity. Surely the introduction of cattle to India as a means of survival by a species whose intelligence…

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    2. James Hill

      Industrial Designer

      In reply to John Nicol

      The case for the land used for grazing in monsoonal India being different to the land used for grazing in monsoonal Northern Australia is?
      Surely a necessary start for anyone embarking on the expensive comparative study that you imply is needed, John?
      Give it your best shot.
      As shown the Indians have been able to increase the forest cover by planting and the exclusion of cattle.
      Those involved seem to have rated it desirable.
      The First peoples, as you have probably noted, husbanded wallabies by clearing forest glades and regularly burning same off to provide pasture, with the wallabies sheltering themselves in the surrounding scrub.
      And yes, why not have your silage pits of harvested grass.
      Though I can see them being robbed for methane production or secondary biodiesel, probably to pay off some debiltating debts.
      Debt, and the threat of death through starvation, being the drivers of environmental destruction in underdeveloped countries, in my opinion.

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    3. Ben Moore

      Lecturer, Hawkesbury Institute for the Environment, University of Western Sydney

      In reply to John Nicol

      Ironically, we already have a massive network of these pits. Millions of years worth of plant growth was added into them during the Carboniferous, conveniently at a time before bacteria evolved the ability to rapidly decompose cellulose and lignin as they do today. The biomass in these pits was compressed and has been safely stored as extremely carbon- (and energy-) rich coal, oil and gas ever since. But what do we do? Dig it up and burn it!

      Many people have investigated a related technique of artificially sequestering carbon, howeve. When we pyrolyse woody and leafy material (i.e. burn it in the absence of oxygen), we create charcoal or biochar, which can be ploughed back into the soil. There, it offers benefits to plant growth as well as locking away carbon. Whether this can ever be done on a large enough scale to make a difference to atmospheric CO2 levels is a matter of debate.

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    4. David Arthur

      resistance gnome

      In reply to James Hill

      Thanks James. I understand that native forest-dwelling cattle remained relatively small, with relatively minor impact on forests, and that larger cattle were as much selectively bred from these original forest-dwellers as introduced with human invasions.

      I also understand that the bulk of Indian deforestation has been due to humans, much of it during the British Raj; it takes a big grazer, like an elephant, to create savannah.

      "This Fissured Land: An Ecological History of India", by Madhav Gadgil & Ramachandra Guha, published 1994, might clarify some of these issues for each of us, less so for John Nicol.

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    5. John Holmes

      Agronomist - semi retired consultant

      In reply to James Hill

      I may be mistaken, but do not ignore the role of fire & frequency/timing and intensity.

      My personal observations over parts of the Top End seemed to show a strong correlation between woody plant density and cattle grazing. Graze too much, and you get many more woody plants. However there was rarely sufficient to support high intensity crown fire.

      Re creating rainforests will depend on substantial fire suppression. Wish you luck on that one.

      I was working on managing native Needle bush…

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    6. James Hill

      Industrial Designer

      In reply to John Holmes

      There was a New Scientist article about 1990, sorry can't be bothered looking through my files for the copy, which quoted the First peoples of the NT concerning their mosaic pattern of cold burns.
      "I we didn't burn, the fuel would just build up and a big fire would destroy everything".
      The undefeatable logic behind thousands of years of successful environmental mangement.
      But it is good, John, to get some input from an Agronomist.
      Do you think that there is a good understanding of Agronomy in the general population?
      There seems to be absolutely no inclination to study any thing about geology among environmentalists, would it be similar with agronomy, even though both disciplines are deeply connected with, duh!, the environment?
      Please pardon the sarcasm., but a little study of these subjects might be a small sacrifice in the saving of the planet, but somehow it is all just too, too hard for the suburban, "educated" elite.

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    7. greg fullmoon

      being and doing

      In reply to James Hill

      The reference to uninformed environmentalists is valid. I'm moderately active as an environmentalist and realize my scientific illiteracy in many of the fields of Earth science.

      I'm reading into stuff all the time.. most recently CEP Brooks 'Climate through the Ages'.. the revised version.

      Of course there is much more modern material to access, however it was rewarding to have Brooks talk me through his logic..

      I'm from New Zealand, originally OZ, and the debate here is vigorous in respect…

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    8. James Hill

      Industrial Designer

      In reply to greg fullmoon

      Thanks Greg, I only did a year of geology at the tertiary level, but as you say, it is not so boring, considering that everyone walks around on it everyday.
      Ultimately posession is nine tenths of the law and so perhaps we own the earth we walk on.
      So why is there an embargo on discussing the science?
      I get sick of all the urging, for everyone to rise up and trounce the evil doers, orchestrated by a few zealots who cannot explain where they got their special, inside knowledge.
      They are all a bit anti-science in the end.

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    9. greg fullmoon

      being and doing

      In reply to James Hill

      Well the wizard is clever, but in being clever he is powerful.. and look what he hath done..

      the World in which we live..

      The World is screaming.. it wants the rate of change to slow..

      It wants the new introductions to be thought out..

      And it wants us to take a few backward steps and move in different directions..

      All the World is plotted on a bell curve of Intelligence.. not every one is a scientist.

      Even those on the far left of the graph have a right to a life unimpeded…

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    10. John Holmes

      Agronomist - semi retired consultant

      In reply to James Hill

      Re Agronomy and the wider population. Agronomy is applied ecology using all tools economically and socially available.

      Comment first - re "...The undefeatable logic behind thousands of years of successful environmental management...." For whose benefit? Got to be a bit careful as history is written by the winners. Which species died out? Yes it was stable, yet what about the pockets of rainforests in the Top End?

      Q2 first: "the answer lies in the soil..". Also if you do not take…

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    11. James Hill

      Industrial Designer

      In reply to John Holmes

      See, I knew it was an interesting subject.
      Years ago some engineering friends built an unusual house which was eventually written up in a popular magazine.
      I asked one of them how the journalists got all the special details right, and said he that that was because he wrote it himself.
      Perhaps the same has to be applied to explaining key subjects like Agronomy to the general public.
      Convential Journalism has just failed in too many areas of knowledge essential to the general understanding.
      Perhaps that is what "The Conversation" is all about.
      When The New Scientist magazine first came out in 1958, the publisher, noting the failure of previous attempts to popularise science in magazines, told the principals that the articles must be understood by the ordinary "man" in the street.(1958 remember).
      Scientists who are also journalists emerged.
      If I might say so, you did a good job on "What is Agronomy" John.

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    12. James Hill

      Industrial Designer

      In reply to greg fullmoon

      Yes well done. greg.
      Many will benefit from reading your post.
      One small point of disagreement; those conducting the Spanish Inquisition fit your definition of activism, so it is not all good.

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    13. greg fullmoon

      being and doing

      In reply to James Hill

      Hi John,

      Funny 1958 is a very good year, I just snuck in toward the end of it..

      On the New Scientist and other 'Science' journals, I want to read the papers.. I'm not part of an institution, they're inaccessible to me..

      I've found ways sometimes to get behind the paywall by trolling other blogs and references to them.. but mostly door slammed shut..

      So here I'm reliant on the journo or a private internet search on the same subject.. Wikipedia is wicked here as it is getting updated all the time.. the open society is desirable but some way away just yet..

      So the activist finds it difficult to access the science that the Scientists say they want to share.

      Some will put their findings in papers in other accessible places but this isn't yet an encouraged activity by the pooh--bahs..

      Till then it is an abstract World.

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    14. greg fullmoon

      being and doing

      In reply to James Hill

      Perhaps this is correct, however the activists that were behind stamping out heterodox belief and practice in the Inquisition were the Authorities (church and state = Authority) seeking to maintain control of the minds of the mass.

      It then flows that the people at the Chicago School of Economics who give us economic rationalism and neo-liberalism are activists.
      As are the folks who proposed the PNAC (Project for the New American Century).. with it's references to the project taking a long time…

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    15. James Hill

      Industrial Designer

      In reply to greg fullmoon

      Demonising their opponents in order to sway the public masses through emotions rather than by reason.
      That is the boring part about activists, they start with a paranoid, losers' perspective and have the martyr complex built in, they project their own totalitarian methodology upon their opponents , fighting fire with fire, they have a hero complex as well.
      I prefer arguments from principle, such as when the philosopher Aristotle proposed a written constitution to govern society, and which opposed…

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    16. greg fullmoon

      being and doing

      In reply to James Hill

      Hi James, what would you put in your constitution?

      What rights would the future have in it?

      What rights would the biosphere have?

      Would the election process by a free market, or publicly funded?

      What would your constitution say about the issuance of money?

      Would government have the prerogative to spend money into existence to pay for public assets, by-passing the need to borrow? It is difficult to argue that this is inflationary where it creates productive classes of infrastructure…

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    17. James Hill

      Industrial Designer

      In reply to greg fullmoon

      greg, on the KISS principle, and on the understanding that everyone must understand the constitution, I would base it on the four International Greens Principles, and the seven International Co-operative Principles, (sorry they are out there on the internet somewhere) which are already inaction just waiting for morepeople to take their guidance as Aristotle might have wished.
      This aint no utopia!

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    18. James Hill

      Industrial Designer

      In reply to greg fullmoon

      Yes greg, though I find the pillars analogy to be inadequate, preferring them to be presented in a dependent hierarchy; No planet without peace, no peace without justice and no justice without democracy.
      Otherwise "activists" tend to hijack a single principle out of its context and trundle off chaotically with their single issue wheel barrows.
      Since the beginning of time four wheeled carts have been able to carry more than four individual wheel barrows.
      If we are allowed to be so mundane in our examples.
      Though wheel barrows are good, they do not really represent the spirit of Co-operation.
      Great scope for an extended rave on this one.

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    19. greg fullmoon

      being and doing

      In reply to James Hill

      Hi James,

      Last words on this thread,

      I like the analogy to insects, social insects..

      We think we are smart.. we compete..

      the hive is run on the base of co-operation.. a tad simplistic??

      I agree the rave is very timely and thank you for sharing, I've gained from the exchange.

      In NZ we are in the process of revising the Constitution.. we are largely founded in Case Law, and of course the 1840 'Treaty of Waitangi' who has its birthday in the sign of Aquarius.

      And funny Australia…

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  5. Peter Fleming
    Peter Fleming is a Friend of The Conversation.

    Leader, Wild Canid Theme, IACRC at University of New England

    Nice explanation, Peter.

    Questions: Are regrowth and actively growing plantations better at sequestering C than mature forests?
    What role do grasslands play in C sequestration; these are the sources of most animal protein consumed by people?

    Graphed models showing time series of net C sequestered in different ecosystems, including various forest and woodland types, would be a useful tool to demonstrate the dynamics of C sequestration and release. Using these models would also identify those parameters we don't have a good handle on, thereby directing research.

    The discussion on this article contrasts in tone and contenet with the comments associated with Nicky Phillips' article, Climate campaigner's carbon warning on 4th June in The Land:
    http://www.theland.com.au/news/agriculture/general/news/climate-campaigners-carbon-warning/2659412.aspx?page=3
    There is still some way to go in shifting some views.

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  6. Peter Innes
    Peter Innes is a Friend of The Conversation.

    ag science research

    You state that 'The world’s forests are a net carbon “sink”' but this surely depends on what spatial or temporal scale this is being measured. Longer term climate changes may have in the past reduced or increased worldwide forest areas and total carbon they have stored. Smaller areas may cycle through growth and regrowth due to disturbances such as fire. Once a forest reaches maturity and remains in that state - and perhaps that only applies to some rainforests, I would have thought the carbon cycle would be more or less in balance rather than a net sink.

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    1. Gary Murphy

      Independent Thinker

      In reply to Peter Innes

      I would have thought that it is a once off thing. Growing a forest sequesters Carbon until it has finished growing and then sequesters no more. And that Carbon will be released again if the trees are again cleared or burnt. Maybe if the logs were then buried it could be done continuously. Or you could use them for biomass electricity generation to replace coal generation.

      Also do forested areas release different amounts of methane to grassland areas?

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    2. Mark Duffett
      Mark Duffett is a Friend of The Conversation.

      logged in via Twitter

      In reply to Gary Murphy

      I have essentially the same question as Peter Innes and Gary Murphy: Since trees don't live forever, isn't there an effective upper limit to the carbon a given area of forest can store? If so, what is it? If not, where is it ultimately ending up? Can or does carbon keep building up in the soil indefinitely as dead trees break down?

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    3. Mark Poynter

      Forester

      In reply to Mark Duffett

      Mark, Gary

      Australian forests would have reached the maximum carbon carrying capacity just before they reach 'old growth' somewhere around 250+ years old, at which point they virtually don't grow anymore and are probably in net decline as the trees senesce and decay. Soon they start to die, and the rotting increases, and eventually they are typically burnt by fire, and the whole process starts all over again.

      Those wet old growth forests (the really iconic ones) that don't burn, may be gradually…

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  7. Ian L. McQueen

    Retired

    This is a perfect example of assumerism in action; it is assumed that carbon dioxide controls climate and therefore all that must be done is to suggest ways in which our "emissions" of carbon dioxide can be reduced. What we should be doing is going back to the original sources of (mis)information and verifying for ourselves that what is said is actual fact. What we will find is that the warmist scare is based only on computer models, models that have never been proved nor validated and which are…

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    1. Gary Murphy

      Independent Thinker

      In reply to Ian L. McQueen

      Yes - it assumes that the experts who have spent their entire lives studying the phenomenon actually know what they are talking about. Ridiculous really.

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    2. Michael Pulsford

      logged in via Facebook

      In reply to Ian L. McQueen

      You're right, carbon dioxide doesn't control climate. All kinds of things affect climate, including water vapour, which you rightly point out there is much more of in the atmosphere than CO2. But it doesn't follow from that that we can keep adding CO2 to the atmosphere without ill effects. For a parallel example - salt is a very small part by weight of our diet, and it's present naturally in most foods, but if we keep adding an ever-greater amount to our diet each day than is present there naturally, we will get sick.

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    3. Peter West

      CEO at Property

      In reply to Gary Murphy

      Well, a lot of this "science" is driven by social agendas. The oft-quoted IPCC is not composed of scientists.
      Just one example where the IPCC relies on the science that has been discredited is when Wei-Chyung Wang (who published research on Chinese measuring stations, relating to urban effects on warming) was publicly accused of fraud. (Hansen, et al,. "Climate Forcings in the Industrial Era" Proceedings of the National Academy of Science, Vol 95, 12753, 1998).
      There are many other examples…

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    4. Gary Murphy

      Independent Thinker

      In reply to Peter West

      The earth has warmed very quickly recently.
      The radiative forcing properties of greenhouse are well understood and physically quantified.
      Greenhouse gas concentrations have increased very quickly recently.

      Solar activity has some influence - as everyone already agrees. But it is not significant when compared to the radiative forcing of greenhouse gases.

      Interesting comment about sudden warming periods in the geological record. The Milankovitch cycle is a slow change over 15,000 years. Yet the geological record does not show a slow change in temperatures over that time period - it shows very sharp increases and decreases in temperature. There are obviously positive feedback processes involved. Again the radiative forcing of greenhouse gases explains this.

      Good idea to plant lots of trees (not pine though - pine forests are environmental dead zones). Unfortunately the trees won't grow very well if there is not fairly regular rainfall.

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  8. Cesar Terrer

    logged in via Facebook

    Hi everyone,

    As far as I know, nowadays the terrestrial carbon sink activity is decreasing (Canadell et al., 2007 PNAS). However, there are differences among biomes (Pan et al., 2011 Science). As Peter said, tropical forest have lost sink effectiveness, due to deforestation (although they compensate in part through regrowth by reforestation and abandonment). In the case of Australian forest, the carbon sink activity seems to have remained constant during this century. So, whats you opinion about future trends of carbon sink activity of Australian trees in the future? My understanding is that two important factors should be considered: i) droughts will become more frequent, affecting growth; and ii) an important part of the current CO2 uptake comes from dynamics of growth resulting from previous disturbances, and cannot be maintained indefinitely.

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    1. John Newlands

      tree changer

      In reply to Cesar Terrer

      I suspect the current warm year will have a bigger impact than many realise. Hot wind gales in January and March in Tasmania killed trees kilometres away from any fire fronts. Old timers tell me they've seen nothing like it. Not all trees are reviving in the current mild drizzly conditions.

      My guess is that the rainforest will retreat. Wet understorey (ferns, dogwood etc) with giant eucs will give way to box woodland with grass. The damp biomass will dry out some of it converting to CO2 and CH4. The net carbon sink will diminish and could conceivably turn into a net source.

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  9. russ george

    logged in via LinkedIn

    The author has missed some key elements in understanding and explaining terrestrial plant ecology and ocean plant ecology as they relate to CO2.

    First: High and rising CO2 has dramatically reduced plant evapotranspiration (ET) and since terrestrial plant ET is the largest source of water vapour in the atmosphere this is dramatically reducing the greenhouse gas warming of by GHG's.

    Remember CO2 is not considered in global warming models as the primary warming agent, rather it is the forcing…

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    1. John Petheram

      logged in via Facebook

      In reply to russ george

      George raised a very important aspect not covered yet in this discussion - i.e. the higher importance globally of ocean photosynthesis in producing oxyge, compared to oxygen produced by forests. However, I can find no evidence that ocean Oxygen production is as high has the 85% of the total, that was mentioned.

      Secondly, the climate science literature does not confirm the statements that "High and rising CO2 has dramatically reduced plant evapotranspiration (ET) and since terrestrial plant ET is the largest source of water vapour in the atmosphere …”. If these statements were true then we should not be seeing increased global humidity, which led to recent violent weather events.

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    2. John Holmes

      Agronomist - semi retired consultant

      In reply to russ george

      Please elaborate on "and since terrestrial plant ET is the largest source of water vapour in the atmosphere this is dramatically reducing the greenhouse gas warming of by GHG's. "

      So there is no effective evaporation of water from the oceans?

      I would suggest you are dealing the the concepts of water recycling in forested areas where local rainfall can be enhanced. Sure after a few years of high rainfall in the center in the early 70's every thing grew well, an the rivers and lakes flowed and filled inc Lake Eyre, yet after the mid level cloud bands from the NW stopped, it all dried up again.

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    3. James Hill

      Industrial Designer

      In reply to John Holmes

      When I first started working across the Riverina in 1975, the road drains were full of water and there were frogs everywhere.
      It dried up, never a frog to be seen hopping about in the car headlights, and it took till 1983 for the drought to break.
      Thanks for the explanation for the presence of the frogs.
      A local Irrigation farmer, Riverina born and bred, argued that the regular pre-war dust storms disappeared with the expansion of irrigation following the Snowy Mountains Scheme.
      Some evidence…

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  10. Will Hunt

    Farmer

    Talking about reveg and tree planting with a bloke who farms near an open cut coalmine in Queensland.
    He said, "Mate, you can plant trees till the cows come home. Won't make any difference. Whatever you can do in a year, the bloody mines will undo in 15 minutes"

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