Arctic plants may not provide predicted carbon sequestration potential

UNIVERSITY OF STIRLING

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IMAGE: SCIENTISTS DR MIKE BILLETT AND DR LORNA STREET CONDUCT MEASUREMENTS OF ECOSYSTEM LEVEL FLUXES OF CARBON DIOXIDE, IN LIGHT AND DARK CHAMBERS. PICTURE TAKEN IN TALL SHRUB BIRCH COMMUNITIES AT… view more CREDIT: UNIVERSITY OF STIRLING

The environmental benefits of taller, shrubbier tundra plants in the Arctic may be overstated, according to new research involving the University of Stirling.

Current ecosystem and climate models suggest that, as the Arctic warms, tundra ecosystems are becoming more productive, with greater photosynthesis resulting in more carbon being removed, or sequestered, from the atmosphere.

However, most models do not consider the transfer and fate of this carbon below-ground, and how this can interact with soil carbon through the activities of soil microorganisms. This is critically important because the vast majority of carbon in Arctic ecosystems is found in soil and ‘permafrost’ (permanently frozen soil or sediment) in the form of organic matter produced by the incomplete decay of dead plants, animals and soil organisms in cold conditions.

The new research considered the impact of a shrubbier Arctic on soil carbon stocks and the overall carbon sequestration potential of these ecosystems. Significantly, it found that some tall shrub communities stimulate recycling of carbon in soils, releasing it back into the atmosphere as carbon dioxide – meaning that more productive shrubs might not always result in greater carbon sequestration.

Professor Philip Wookey of the Faculty of Natural Sciences at the University of Stirling led the Natural Environment Research Council (NERC) funded research programme of which this study was a part. Stirling colleague Dr Jens-Arne Subke was also involved in this work.

Professor Wookey said: “While previous studies suggest that a warmer, greener Arctic may increase the rate that carbon dioxide is removed from the atmosphere, our research identified an acceleration in the rate of loss of carbon from soils, back into the atmosphere.

“This may more than offset carbon sequestration and would, unexpectedly, turn these ecosystems into a net source of carbon dioxide to the atmosphere. Significantly, current ecosystem and climate models do not account for this conundrum, which means we may be underestimating future climate feedbacks from Arctic ecosystems.”

The study was led by Dr Lorna Street, of the University of Edinburgh’s School of GeoSciences, and also involved scientists from the NERC Radiocarbon Facility in East Kilbride, and the Universities of Durham and Liverpool. Further support was received from the Aurora Research Institute, Wilfrid Laurier University, and the University of Montreal, all in Canada.

The fieldwork – looking at how carbon is cycling in plants and soils over the past 50 years – was conducted in 2013 and 2014 in the Mackenzie Uplands of Northwest Territories, Canada.

The team found evidence that birch shrubs in Arctic tundra are strongly linked to the release of old carbon – fixed by photosynthesis more than 50 years ago and stored in soil organic matter. However, this was not true of alder, another type of Arctic shrub.

Dr Street said: “We think this is because, in birch, the products of photosynthesis are transferred to the soil through fungal symbionts, which stimulate the decomposition of soil organic material as a means of releasing the nutrients, like nitrogen, that the birch shrubs require to grow.

“By contrast, in alder, photosynthesis products are mostly retained in plant tissues because alder often has the help of microorganisms in the roots, which are capable of ‘fixing’ nitrogen directly from the atmosphere.

“These findings indicate that, if – as evidence has suggested – shrub birch proliferates in tundra ecosystems over the next decades, this might directly stimulate the loss, through accelerated decomposition, of pre-existing soil carbon as carbon dioxide.”

Uncertainty surrounds the level of potential carbon release from high latitude permafrost systems – with predictions ranging between 0 and 200 gigatons. For context, 200 Gt represents approximately 20 years of current total global carbon emissions, due to human activity, to the atmosphere.

Dr Street added: “If our results apply across permafrost tundra regions, this suggests there is a previously unaccounted for process which could push the system towards the upper end of those predictions. This is hugely important as it means we may need to do more than currently expected, in terms of carbon dioxide emissions reductions, to meet our climate targets.”

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The study, Plant carbon allocation drives turnover of old soil organic matter in permafrost tundra soils, is available now.

44 thoughts on “Arctic plants may not provide predicted carbon sequestration potential

  1. Ten thousand years ago where was tundra , with the warming after the ice age there came forests
    QED

    • Yes, we absolutely have to consider evidence from the past.

      This reminds me of Ian Stirling’s theory that polar bears can’t survive an seasonally ice-free arctic ocean. He knows how polar bears are now. He extrapolates based on that knowledge. As far as I can tell, he ignores the fact that polar bears survived the seasonally ice-free arctic ocean during the Holocene optimum. That’s why Susan Crockford gets it right and Stirling gets it wrong.

      There used to be forests in the arctic. link There were trees not just shrubs. You can’t assume that all you will get will be just shrubs.

      • Evidence from the past tells us that humans, animals and the planet adapt to changes faster than they can kill us. Especially if the past is around 6,000 years, and the Flood was a worldwide catastrophe. A faulty premise, billions of years, leads to failed predictions.

        • Oh dear. A world wide flood? Geologists abandoned diluvionism in the nineteenth century for a reason.

          • Not for a reason. For an ideology. Keep up just about every week scientists find something that will rewrite their books. One book has never been rewritten.

          • There is a lot of land area, formerly inhabited by humans, that is now under water. As we moved into the Holocene, the sea level rose something like 400 feet (120 m). There is a fair amount of underwater archaeology devoted to studying this.

            The final flush of Lake Agassiz caused sea levels to rise 1 to 3 m. link It’s quite possible it happened quickly enough to cause something like a tsunami and recently enough that people remember the event in their oral history.

            Flood stories are common to all the cultures with which I am familiar. link

            Slowly or quickly, the flood did happen.

    • Make that 4,000 years and go to rsr .org /hpt and you’ll find accurate predictions based on secular science.

  2. And the increasing shrub birch growth in tundra zones of the frozen north are releasing so much CO2 that the atmospheric results are plainly visible in the atmospheric CO2 readings at the top of Mauna Loa! We’re doomed to die in a burning hell on earth! What? No signal visible? A big nothing burger? Never mind. But we might die in a burning hell on earth if these arsonists and rioters don’t get dealt with properly. What about the CO2 they’re producing? There’s an inconvenient truth!

  3. Uh-oh, this must mean – gasp, that IT’S WORSE THAN WE THOUGHT. Again. For the bazillionth time.
    Yawn.

    • I think their conclusions are obtuse. They fail to mention trees (which already exist across the tundra but can barely grow). Notice these alarming articles almost never mention the age of the carbon that is being released. In this article they say “50 years”. What the heck? Since when was carbon being laid down in the tundra 50 years ago? Was it melted, grew and froze again? No.

      The biomass being melted by rising Arctic temps was put there the last time it was much warmer than now, a thousand or thousands of years ago. Look at it. Is it made up of little alders? Is it pinus and birches?

      What happens if the permafrost stays melted (each summer)? Trees grow, of course!

      Have a look at the forests around Arctic Red. That is where the huge trees came from to build the Inuvik Friendship Centre – an enormous log building. They cut the trees at Arctic Red and floated them down the river. Arctic Red was frozen solid permafrost not that long ago. Now there are forests. Why are these authors whining about carbon released that is only 50 years old? Are they serious? How do you get a calamity out of that?

      The whole of Canada used to be covered by permafrost with essentially no trees at all. When it melted, surprise, surprise, trees grew to cover it, unless there is a lot of human management to create grassy meadows. I would much rather have trees and meadows full of deer, than ice.

      • Right on Crispin. “Dwarf Birch” (Canadians call them) become regular birch when the climate warms and the treeline marches northward.

        When we were heading for the Glacial Maximum, the march was southward and trees of the previous interglacial taiga found themselves populating much of the northern half of the USA. When it melted back, those taiga varieties not only marched back up north but also west, climbing to the upper slopes of the Rockies where taiga ‘weather’ was preserved – Colorado etc.

        BTW, the roots of those flimsy looking Dwarf Birch are quite unexpectedly, fat and almost impossible to pull out of the ground. They are ready to shoot for the sky when things warm up. Arctic Grayling (a black trout) smoked using the thick roots are a gourmet delight!

  4. The environmental benefits of taller, shrubbier tundra plants in the Arctic may be overstated, according to new research involving the University of Stirling.

    It would be wouldn’t it

  5. So maybe they didn’t think about this. Birches are white but alders are shrubs of Color. No wonder the “birch communities” are bad for Mother Earth. No climate justice, no climate peace.

  6. “Uncertainty surrounds the level of potential carbon release from high latitude permafrost systems – with predictions ranging between 0 and 200 gigatons. For context, 200 Gt represents approximately 20 years of current total global carbon emissions, due to human activity, to the atmosphere.”

    Say what? You can’t narrow it down between 0 and 200 gigatons? I note that you are not giving a time frame for this “potential carbon release”. A year? A decade? A century? Why are you even publishing this “study”?

    The only thing this waste of money proves is that compared to the natural CO2 fluxes, human emissions are background noise.

  7. I have lived in the Arctic, the winter and frozen ground kills bacteria that causes rot and the release of methane. The surviving bacteria acustom to the cold is extremely slow at metabolizing. (tundra has very little sugar content) As a result, large amounts of tundra builds up for centuries. Carbon dioxide levels go down in the summer even though there is 24 hour sunlight. This indicates that any carbon dioxide released from the tundra is being absorbed faster than it can be emitted. If you have a potted plant with Pete around the roots, you can measure the rate of the decay for yourself.

  8. Are any of their predictions ever “right”? Within 5% of what they expect? Of course we wouldn’t read an article with the headline “We don’t know anything but give us money to study it anyway”. At least that would be honest. That is why NO, ZERO, NADA taxpayer money should be used for science. The government demands nothing, private investors demand results. If it is important, then private individuals, by creating organizations, should choose to fund it and profit from the results.

  9. Am I mistaken? I thought birch grew in numerous locations where it is cool and moist. Why focus on the Arctic only? Are birch trees a really bad species that should be eliminated everywhere? I sense a money making prospect arising.

  10. “expected carbon sequestering”

    expected by whom exactly?

    Did anyone ask the plants? Because if you talk to them, they’ll say, “you idiot, you want me to starve even more?”

    Why do I feel as if the true purpose of this study was to “prove” that plants don’t really need that much CO2 in order to live? They only “need” a little bit in the Arctic, so you know, humans bad again.

  11. “Arctic plants may not provide predicted carbon sequestration potential”

    But there again, they may. OK, stop reading now.

  12. Are not plants grown from CO2? Are they saying that warming leads to less plant matter in the Arctic? Are they saying that the locally enriched CO2 environment in such areas does not lead to increased growth of other plants? So many questions.

  13. Flea bites can be made to look very alarming under a powerful microscope if you have the mind and grant funds to do it.

  14. Arctic plants need to shape up and buckle down and do the job they are supposed to do: sequester “carbon”. Otherwise, we will sic Al Gore on them. And if that doesn’t work, Greta will go bark at them.

  15. I thought the heavy lifting in carbon sequestration was being done by seashells and limestone. Where I live there’s hundreds of feet of Ordovician limestone underneath. There is a reason there is so little carbon dioxide in the atmosphere. It’s because it quickly gets metabolized from a gas into solid stuffs such as carbonates. Someone calculate how much CO2 there would be in the atmosphere if all of earth’s limestone were converted to gas. If it’s true that the weight of the atmosphere only amounts to the weight of 33 feet of water, you would have something like Venus’s atmosphere where not only is the concentration higher but there is more of it.

  16. Blaming CO2 for warming is shallow penetration of science/physics. Analysis using data from Quantum Mechanics calculations by Hitran reveals that water vapor increase has caused about 10 times more ground level warming than CO2 increase. The cooling effect of more CO2 in the stratosphere apparently cancels the small contribution to warming of more CO2 at ground level with the result that CO2 has no significant effect on climate.

    WV has been increasing about 1.5% per decade which is MORE THAN IS POSSIBLE from feedback from temperature increase. Most (about 96%) of the WV increase is a result of irrigation increase. All of the human contribution to climate change (about half of the total increase since 1909) is a result of increased water vapor. http://globalclimatedrivers2.blogspot.com

  17. Actually the cited research is quite illustrative once one gets past a personal stance on the CO2 level’s significance. The salient point is how fungal soil activity influences the carbon cycle.

    It means that linear interpretations of all plant communities functioning similarly in cycling carbon can not be assumed. Years ago I used to brew compost “tea” for different types of plants & in some situations formulated for plants which benefitted from brews with lots of fungal micro-organisms.

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