From the University of Exeter , terrible news:
Carbon stored in Arctic tundra could be released into the atmosphere by new trees growing in the warmer region, exacerbating climate change, scientists have revealed.
The Arctic is getting greener as plant growth increases in response to a warmer climate. This greater plant growth means more carbon is stored in the increasing biomass, so it was previously thought the greening would result in more carbon dioxide being taken up from the atmosphere, thus helping to reduce the rate of global warming.
However, research published in Nature Climate Change, shows that, by stimulating decomposition rates in soils, the expansion of forest into tundra in arctic Sweden could result in the release of carbon dioxide to the atmosphere.
Dr Iain Hartley now based in Geography at the University of Exeter, and lead author of the paper, said: “Determining directly how carbon storage is changing in high-latitude ecosystems is very difficult because the majority of the carbon present is stored below ground in the soils. Our work indicates that greater plant biomass may not always translate into greater carbon storage at the ecosystem level.
“We need to better understand how the anticipated changes in the distribution of different plant communities in the Arctic affects the decomposition of the large carbon stocks in tundra soils if we are to be able to predict how arctic greening will affect carbon dioxide uptake or release in the future.”
By measuring carbon stocks in vegetation and soils between tundra and neighbouring birch forest, it was shown that compared to tundra, the two-fold greater carbon storage in plant biomass in the forest was more than outweighed by the smaller carbon stocks in forest soils.
Furthermore, using a novel methodology based on measuring the radiocarbon content of the carbon dioxide being released, the researchers found that the birch trees appeared to be stimulating the decomposition of soil organic matter. Thus, the research was able to identify a mechanism by which the birch trees can contribute directly to reducing carbon storage in soils.
“Dr Gareth Phoenix, of the University of Sheffield’s Department Animal and Plant Sciences, who collaborated on the research, added:
“It shows that the encroachment of trees onto Arctic tundra caused by the warming may cause large release of carbon to the atmosphere, which would be bad for global warming.
“This is because tundra soil contains a lot of stored organic matter, due to slow decomposition, but the trees stimulate the decomposition of this material. So, where before we thought trees moving onto tundra would increase carbon storage it seems the opposite may be true. So, more bad news for climate change.”
The results of the study are in sharp contrast to the predictions of models which expect total carbon storage to increase with the greater plant growth. Rather, this research suggests that colonisation by productive, high-biomass, plant communities in the Arctic may not always result in greater capture of carbon dioxide, but instead net losses of carbon are possible if the decomposition of the large carbon stocks in Arctic soils are stimulated. This is important as Arctic soils currently store more carbon than is present in the atmosphere as carbon dioxide and thus have considerable potential to affect rates of climate change. It is yet to be seen whether this observed pattern is confined to certain soil conditions and colonising tree species, or whether the carbon stocks in the soils of other arctic or alpine ecosystems may be vulnerable to colonisation by new plant communities as the climate continues to warm.
The research took place within the Natural Environment Research Council (NERC)-funded Arctic Biosphere Atmosphere Coupling at Multiple Scales project (ABACUS; www.abacus-ipy.org) which was led by the University of Edinburgh. This particular study was carried out by a team from the University of Exeter, University of Stirling, NERC Radiocarbon Facility, James Hutton Institute (Aberdeen), the University of Sheffield, and Heriot-Watt University.
What a nonsense… During the previous warmer interglacial, forests were growing up to the Arctic Ocean in Alaska and Siberia with temperatures 5-10 degr.C higher than now. Probably most if not all permafrost melted away and the Arcticwas at least in summer completely icefree… CO2 levels were 300-310 ppmv and CH4 levels maximum 700 ppbv. So where is the problem?
Apart from the fact that the science is settled …
It is yet to be seen whether this observed pattern is confined to certain soil conditions and colonising tree species, or whether the carbon stocks in the soils of other arctic or alpine ecosystems may be vulnerable to colonisation by new plant communities as the climate continues to warm.
… nothing ever seems to be settled in climate science.
This is a very strange paper, since there is actually very little real tundra in Sweden. The treeless areas in the mountains are typically montane heath, but with little or no permafrost.
There may however be another reason for this “discovery” at this particular time. Sweden’s main (state-owned) mining company LKAB is planning a large increase in production of iron ore which will of course mean more CO2 “pollution”, and has suggested that rather than buying more CO2 emission rights on the EU-market they should spread fertilizer on the very slow-growing and nutrient-poor forests in northern Sweden (with the enthusiastic approval of the landowners). The forests would then grow faster and absorb far more CO2 than emitted by LKAB in addition to producing additional timber and biofuel, but the idea has been fiercely resisted by EU environment bureaucrats.
This is very likely paid-for “research”.
Tundra terrains have higher levels carbon sequestered in the ground because it is too cold for biomass decomposition to keep up with annual production. Forests only exist where it is warm enough for production and decomposition to approach a balance. But, by the sterling logic of these yaboos, it is the trees that are to blame for the difference in carbon levels in the soils. It is definitely hard to argue with those kind of intellectual powerhouses.
tty says:
June 18, 2012 at 12:50 pm
This is a very strange paper, since there is actually very little real tundra in Sweden. The treeless areas in the mountains are typically montane heath, but with little or no permafrost.
There may however be another reason for this “discovery” at this particular time…..
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Thanks for the inside story. Ain’t Politics grand?
Mike M says (June 18, 2012 at 5:50 am): “Ummm, the machines are real.”
But do you have a model that runs on solar? 🙂
I read up on Tree Line levels a year or two ago, and most research up to around 2008 seemed to indicate that the tree line had not shifted north.
Perhaps I am mistaken, but as the above paper does not speak to the supposedly advancing (necessary for their hypothesis to be correct) tree line that I would question its research in how it ascertains that the arctic is greening any more than it has been lately.
Did I miss something?
A published study showing the Holocene treeline was higher than current. http://pubs.usgs.gov/pp/1782/ about 9,000 years ago. Anther story on Holocene beingwarmer than today (about 3.5C warmer) http://www.sciencedaily.com/releases/2011/12/111214094650.htm
Now another paper talking about how tree ring growth stopped following temperature rise around 1950, but that wood density is making up for it (shorter growth years would seem to lead to denser wood – but what do I know) http://eyeonthearctic.rcinet.ca/en/news/usa/97-environment/1385-rising-temperatures-affecting-alaskas-treeline
Paywall treeline article that would be interesting to readhttp://accessscience.com/abstract.aspx?id=YB061230&referURL=http%3a%2f%2faccessscience.com%2fcontent.aspx%3fid%3dYB061230
So, if the treeline was higher and further north 9,000 years ago, how much carbon could actually have been stored in the Arctic tundra between then and now, that would be at risk of being released, if (somehow) we gained the 3.5 extra degrees needed to match temperatures found then?
cui bono says:
June 18, 2012 at 4:37 am
I look back on those Thunderbirds clips and now see them as anti technology.,so how long has this really been going on?
DaveE.
Richdo says:
“…the researchers found that the birch trees appeared to be stimulating the decomposition of soil organic matter.”
Well of course they do. co2 is their primary food; more is better. Not surprising that they’d have evolved mechanisms to stimulate it’s release into a useable form. Seems the trees are smarter than the “climate scientists” studying them.
The obvious question to ask would be “What’s the optimal level of carbon dioxide for the tree species in question?” The most likely reason for ignoring this question is that the answer is several times greater than that which the “scientists” think is “too much”.
No doubt an actual scientist would be more interested in what appears to be a mutualistic relationship between trees and soil organisms which decompose organic matter in the soil
richard M says:
June 18, 2012 at 9:01 am
“The Arctic is getting greener as plant growth increases in response to a warmer climate”
I would like to see this statement quantified as it’s broad brush is foundational to this….study.
Here y’go: “The robust projections of our models suggest that the Arctic is probably getting quantifiably, catastrophically greener as plant growth is likely to increase in a possible response to what we can say with a high probability is a warmer climate.”
Mark says:
June 20, 2012 at 12:05 am
No doubt an actual scientist would be more interested in what appears to be a mutualistic relationship between trees and soil organisms which decompose organic matter in the soil.
It’s more likely ro be a result of the tree roots aerating the soil by displacement, which allows the aerobic bacteria in the soil to get to work releasing the nutrients the trees need.