Trees worsen greenhouse effect!(?)

by egoigwe | May 15, 2007 at 07:14 am
850 views | 12 Recommendations | 6 comments

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Hamburg- A leading expert in Germany has spawned a major scientific debate by claiming that trees put millions of tons of methane into the atmosphere every year exacerbating the greenhouse effect. Amid controversy, Dr Frank Keppler of the Max Planck ...



Hamburg- A leading expert in
Germany has spawned a major scientific debate by claiming that trees
put millions of tons of methane into the atmosphere every year
exacerbating the greenhouse effect. Amid controversy, Dr Frank Keppler
of the Max Planck Institute for Chemistry has reaffirmed findings by
his team in Mainz, Germany, in January 2006 that they had detected
methane exhaled from living plants.



"I am 100 per cent confident that plants emit methane," he told
Chemistry World magazine, insisting that as yet unpublished research
would confirm his findings once and for all.



Keppler's unexpected discovery has caused heated debate among
biologists and atmospheric chemists. Though bacteria in soil or
decaying matter produce methane in anaerobic conditions, there seems to
be no reason or mechanism for living plants to emit the gas in an
oxygen-rich environment.



The implications of the findings are worrying: on a global scale,
Keppler estimated, methane emissions from plants and trees could amount
to hundreds of millions of tonnes a year, throwing scientists'
understanding of the greenhouse gas's sources and sinks way off kilter.




But many researchers have queried the global impact, suggesting that
Keppler's scale-up calculations, based on methane emission per unit of
metabolically active mass of plant, were a gross overestimate.



Yet until recently, no published research has questioned Keppler's
central discovery that plants can emit methane in the first place.  Go to original story 

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0
ScienceDave

I would like to see the original link to the text you're refering to. 

I remember first reading this in Nature and thinking, "No way! That is impossible!"

The issue of criticism they received, including from my cramped student office, is that they fail to provide an actual biochemical mechanism for the production of methane.  Without a mechanism, it remains ambiguous WHAT was actually producing the methane (i.e. was it an experimental artefact?) 

"But many researchers have queried the global impact, suggesting that

Keppler's scale-up calculations, based on methane emission per unit of

metabolically active mass of plant, were a gross overestimate."

 ---Do ALL trees produce methane, never mine the same amount? What environmental parameters controls the production of methane, and to what extent?

[q
url="http://www.nature.com/nature/journal/v447/n7140/full/447011a.html"]Tom
Dueck of Plant Research International in Wageningen, the Netherlands,
and his colleagues say that they can find no evidence that plants
produce the potent greenhouse gas...


...One reason that the matter has not already been settled is that
the amount of methane produced by each plant is low relative to the
ambient methane concentration. To tackle this problem, Dueck and his
team grew plants in an atmosphere of 'heavy' carbon dioxide enriched in
the isotope carbon-13 to give any methane produced a recognizable
isotopic signature. But their studies detected no significant methane
emissions (New Phytol. doi:10.1111/j.1469-8137.2007.02103.x; 2007).[/q]

Something with more merit:

"Total
emissions are known pretty well from the top down," [Ed Dlugokencky of
the Earth System Research Laboratory in Boulder, Colorado] says. "If
methane emissions are coming from forests then that probably just means
less from wetlands."

Essentially, the total global methane budget is known, just not the exact degree in which all the players in it play. 

0
egoigwe

 ..One reason that the matter has not already been settled is that

the amount of methane produced by each plant is low relative to the

ambient methane concentration.

Well, would that be admitting that plants do produce methane? If it is true won't it follow that there must be some mechanism for that production present? 

Ego

0
ScienceDave

According to the original study you refer to, the amount of methane is low per individual plant.  However, Dueck's team found no evidence for methane production, even when using heavy carbon as a tracer.

I agree, if methane was present there is a mechanism responsible.  However, to date there has been no evidence for methane production by plant macrofauna.  This is why it is key to provide the mechanism, as it is completely novel.

I feel I should emphasize Ed Dlugokencky's comment again, as it pertains directly to the potential climate effects if methane is produced by trees.  If the "top down" emissions are well constrained (i.e. the entire methane budget on earth), then the estimates of individual methane reservoirs (and fluxes betwen them) of the global methane cycle are likely to be incorrect at the moment.

moonwolf
moonwolf
flagged this story as Good Stuff

at 12:23 on May 15th, 2007

In complex biological systems nothing is ever as simple as we'd like!


Good stuff and very interesting.  The relevant question if this is true would be does the ability of trees to fix carbon from the atmosphere exceed the negative effect of their production of methane?


 


 

ScienceDave
ScienceDave
flagged this story as Good Stuff

at 14:08 on May 15th, 2007

I agree, Great stuff!  This sort of work needs to be brought to the attention
 of the general public.

0
alvinwriter

I don't think there's any problem with findings like these if they are part of the natural processes. What we can do is try to mitigate the artificial release of greenhouse gases which may go beyond being manageable through natural means.

Some deforestation may help offset global warming: study: http://www.thenewsroom.com/details/189694?c_id=wom-bc-ar

Find more news on global warming you can use in TheNewsRoom. Email jtowns@voxant.com to find out more. We'll be happy to hear from you.

 - Alvin from TheScienceDesk at TheNewsRoom.com

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