Support the Arctic Sea Ice Forum and Blog

Author Topic: Woods and Trees: Embodied carbon and albedo  (Read 2378 times)

GeoffBeacon

  • Frazil ice
  • Posts: 378
    • View Profile
  • Liked: 7
  • Likes Given: 5
Woods and Trees: Embodied carbon and albedo
« on: February 01, 2014, 06:05:23 PM »
Should we count wooden things (e.g. wooden furniture, wooden houses) as sequestered carbon. The Ice Database on embodied carbon in building materials says

Quote
The following extract was taken from A. Amato "A comparative environmental appraisal of alternative framing systems for offices' 1996, Reference 1: ‘There are counter arguments against taking sequestered CO2 into consideration. in measuring embodied CO2, what is being sought is the CO2 burden to society which consequent upon society's use of a particular material. The deduction of a CO2 value sequestered by the material during its manufacture from the total embodied CO2 burden is not appropriate just because a material is deemed renewable and is surely only appropriate when a world wide steady state has been achieved between consumption and production, i.e. it has achieved sustainability.

Renewability does not automatically confer the attribute of sustainability to a material. if we consider the world resource of timber and its consumption as a complete system, then clearly much greater quantities of timber are being consumed than are being replenished at present, most being consumed as fuel in third world countries. Thus, in terms of anthropogenic CO2 resultant from the worlds use of its timber resource, more is being released into the atmosphere than is fixed by the renewal of timber in new plantations and by natural seeding. it therefore appears that the sequestered CO2 argument is only applicable where a steady state has been achieved.

...Finally, it seems a somewhat dubious practice to credit timber benefit of sequestered CO2 without taking into account the methane emissions resultant from the disposal of timber.

Methane, like CO2 is a greenhouse gas, but it is estimated as being 24 times more potent than carbon dioxide as stated previously. It is emitted in the UK, mainly from landfill waste, animals, coal mining, gas pipe leakage and ofishore oil and gas operations. Methane is produces as timber bio-degrades in landfill sites. '

Does this mean it is not possible to use wood for carbon sequestration?

Quote
A new house is about 80 tonnes of CO2: http://www.theguardian.com/environment/green-living-blog/2010/oct/14/carbon-footprint-house .  This suggests building in wood may be beneficial but Amato implies that it would be less valuable as sequestration than, say, Baufritz claim:

Safeguarding our world has always been at the heart of the Baufritz philosophy. Using only timber, installing the best thermally efficient windows and because our construction process is so energy efficient, has ensured our homes have earned the accolade “carbon positive” : they lock away more CO2 than is emitted during their manufacture, transportation and construction.

http://www.baufritz.com/uk/why-baufritz/ecology/
Il faut cultiver notre cité-jardin
The Sustainable Plotlands Association

GeoffBeacon

  • Frazil ice
  • Posts: 378
    • View Profile
  • Liked: 7
  • Likes Given: 5
Re: Woods and Trees: Embodied carbon and albedo
« Reply #1 on: February 01, 2014, 06:19:28 PM »
I had an email exchange with G.Bala from the Lawrence Livermore Laboratory a few years ago and preparing this entry I have just found

Quote
We also showed that the observed change in albedo constituted a direct radiative forcing of 2759 GJ ha−1 yr−1. Thus, following afforestation, 26.5 tC ha−1 needs to be stored in a growing forest to balance the increase in radiative forcing resulting from the observed albedo change. Measurements of tree biomass and albedo were used to estimate the net change in radiative forcing as the newly planted forest grew.

Albedo and carbon-storage effects were of similar magnitude for the first four to five years after tree planting, but as the stand grew older, the carbon storage effect increasingly dominated. Averaged over the whole length of the rotation, the changes in albedo negated the benefits from increased carbon storage by 17–24 %.
http://www.biogeosciences.net/8/3687/2011/bg-8-3687-2011.pdf

What does this mean for tree planting in general - or is there no "in general"?

Il faut cultiver notre cité-jardin
The Sustainable Plotlands Association

Andreas T

  • Nilas ice
  • Posts: 1126
    • View Profile
  • Liked: 11
  • Likes Given: 2
Re: Woods and Trees: Embodied carbon and albedo
« Reply #2 on: February 01, 2014, 06:58:57 PM »
Compensating for carbon released from fossil fuels by storage in a building or a tree with limited lifespan is always dubious. There should of course be a way to account for and incentivise that temporary storage where it genuinely leads to increased amounts of fixed carbon for significant duration.
Assuming that the wood form the house will end up in a methane releasing landfill a considerable timespan into the future is of course flawed. I would guess that it is more likely to be burned as fuel if it becomes available several decades from now.
"negated the benefits ..by 24%" should probably be read as "reduced benefit by 24%"

Reallybigbunny

  • New ice
  • Posts: 77
    • View Profile
  • Liked: 5
  • Likes Given: 47
Re: Woods and Trees: Embodied carbon and albedo
« Reply #3 on: April 25, 2019, 04:18:44 AM »
I didn't know trees released methane. Maybe the destruction of earth's forests is a factor in rising levels of methane in the atmosphere?

https://www.nationalgeographic.com/environment/2019/03/trees-release-methane-what-it-means-climate-change/