from Northern Arizona University
Study finds accelerated soil carbon loss, increasing the rate of climate change
Research published in Science today found that increased levels of carbon dioxide in the atmosphere cause soil microbes to produce more carbon dioxide, accelerating climate change.
Two Northern Arizona University researchers led the study, which challenges previous understanding about how carbon accumulates in soil. Increased levels of CO2 accelerate plant growth, which causes more absorption of CO2 through photosynthesis.
Until now, the accepted belief was that carbon is then stored in wood and soil for a long time, slowing climate change. Yet this new research suggests that the extra carbon provides fuel to microorganisms in the soil whose byproducts (such as CO2) are released into the atmosphere, contributing to climate change.
“Our findings mean that nature is not as efficient in slowing global warming as we previously thought,” said Kees Jan van Groenigen, research fellow at the Center for Ecosystem Science and Society at NAU and lead author of the study. “By overlooking this effect of increased CO2 on soil microbes, models used by the Intergovernmental Panel on Climate Change may have overestimated the potential of soil to store carbon and mitigate the greenhouse effect.”
In order to better understand how soil microbes respond to the changing atmosphere, the study’s authors utilized statistical techniques that compare data to models and test for general patterns across studies. They analyzed published results from 53 different experiments in forests, grasslands and agricultural fields around the world. These experiments all measured how extra CO2 in the atmosphere affects plant growth, microbial production of carbon dioxide, and the total amount of soil carbon at the end of the experiment.
“We’ve long thought soils to be a stable, safe place to store carbon, but our results show soil carbon is not as stable as we previously thought,” said Bruce Hungate, director of the Center for Ecosystem Science and Society at NAU and study author. “We should not be complacent about continued subsidies from nature in slowing climate change.”
Goofballs. A pure positive feedback system. We will shortly have a ~100% CO2 atmosphere, no doubt.
Bill Illis, what is/are the source(s) for your graph?
I’m very sceptical about this carbon in the soil concept.
Both sides of the climate debate cite it. (A few years ago Aussie farmers asked for payment (or a tax break) for ‘all the carbon they put back in the soil’. Apparently Tony Abbott’s government will now grant their request) What carbon?)
I’m sure I’ll be corrected if/where I’m wrong but it seems to me that:
a) Plants in forests, crops, savannah etc. photosynthesize the carbon in atmospheric carbon-dioxide to form sugars and cellulose.
b) The plants die or drop their leaves, twigs, fruit etc. and they lie on top of the soil.
c) Fungi feed on these – i.e. the plant matter starts to ‘rot’
d) Fungi turn cellose back onto CO2 (i.e. they reverse photosynthesis) and thus complete an important sub-cycle of the overall Carbon cycle. (Is this heresy?)
e) The rotting process is not immediate and a bit of ‘humus’ layer builds up as the top layer of the soil.
Is this humus layer the same as the ‘carbon in the soil’ that they’re banging on about? Hell it’s only thin!
Yet the paper says “Soils contain the largest pool of terrestrial organic carbon” – i.e. more than all the Earth’s biomass! I don’t believe this – but I’m still trawling through the references to find out where they got that idea from (so far all the references I’ve found refer to economics papers)
There also seems to be a greenie ‘meme’ in some camps that the Earth’s rainforests have a thick layer of peat under them. Although this is only true of Borneo and a few other forests. It is not true of the Amazon (where the humus layer is thin to non-existent) or the Congo rainforests.
As Ferdinand points out and a couple others intimate, what they are seeing is a rate increase where the same Carbon is cycled faster. The Carbon economy is growing for our efforts and will cycle faster as marginalized creatures begin to dance.
So the warmists have discovered microbial respiration? Someone let them in on decomposition. They will be astonished to find that its byproducts are CO2 and CH4, gasp!
JC(UK)
The greatest reservoir of elemental carbon (organic or not) in the various “-spheres” is in rocks.