Talking about wood products for carbon sequestration, I don't know if you have seen this report from the Wilderness Society, perhaps the most in-depth I've seen? -Ning
http://wilderness.org/files/Wood-Products-and-Carbon-Storage.pdf On Sep 27, 7:55 am, Duncan McLaren <duncan.p.mcla...@gmail.com> wrote: > Thanks for your feedback. It's great to see more detailed work > ongoing, and I look forward to reading your paper. Hopefully I will > get the chance to use it to update my report. > > I agree that sustainable forestry has a role in a package of NETs, but > whether WHS is the best option for some or all of the accumulated > carbon is an open question for me still. Comentators above have argued > for BECCS and biochar. Personally I have a soft spot for timber use in > construction (even if the store is relatively shortlived). > > I agree that there are environmental impacts from most if not all > NETs, and hadn't intended to imply that forestry-related approaches > were particularly bad, simply to highlight that current forestry > techniques are not always sustainable (or ethical for that matter), > and expanding conventional approaches to plantation forestry, for > example, could be counterproductive, even in carbon terms. > > Best wishes > Duncan > > On Sep 25, 4:37 pm, Ning Zeng <z...@atmos.umd.edu> wrote: > > > > > > > > > Hello Duncan: > > > I enjoyed reading through your very nice analysis of NETs over the > > weekend. I agree with Oliver Tickell's comment that we need > > "knowledge, not conjecture". I have been researching on the "wood > > burial" idea which has even less research compared to many others. > > > We have a paper that is in review at Climatic Change, which brings > > more information on wood burial's (we now call it Wood Harvest and > > Storage or WHS) harvest potential, and more information is on the way > > on cost and storage and other practical considerations. The abstract > > of the paper is below. It is relevant to some key factors you > > discussed in your report, including: > > > 1. We use GtC, while you use GtCO2, so that the estimate of Zeng > > (2008) of 10 GtC potential is really 37 GtC/y. However, that is just a > > theoretical potential based on coarse wood production rate of all > > world's forests. In this new paper (Zeng et al. 2011), we consider > > many practical constraints including land use and conservation needs, > > and we arrive at a range of 1-3 GtC/y (4-10 GtCO2/y). > > > 2. This new paper also shows the area of forest needed in order to > > accomplish these sequestration goals. At our low value of 1GtC/y, it > > requires 800 Mha forest land with a (modest) harvest intensity of 1 tC/ > > ha/y, a much lower rate than typically assumed bioenergy crop harvest > > rate. The amount of biomass (2Gt dry biomass) involved is equivalent > > to the current worldwide forest harvest. So this is definitely not > > business-as-usual, but a leap for forestry. > > > 3. The cost estimate of Zeng (2008) of $14/tCO2 was based on cost of > > harvesting. If including storage (mostly in situ around harvest > > landing site to minimize transportation cost), it will probably double > > to $30/tCO2. Adding other unforseen cost, bearing in mind the > > observation that real-world implementation often tends to be more > > expensive, I'd wave my hand (before realistic demo project) to put > > the cost at about $50/tCO2. I think this is actually what you used in > > the cost/potential plot (Fig. 7). > > > 4. I thought it's a bit unfair to apply environmental impact to wood > > burial, while not to other methods. All these have major environmental > > issues to consider, but my feeling is that sustainable forestry, we > > actually know better how to do it right. > > > Best Regards! > > -Ning Zeng > > > Ecological carbon sequestration via wood harvest and storage: An > > assessment of its practical harvest potential > > > Ning Zeng, Anthony King, Ben Zaitchik, Stan Wullschleger, Jay Gregg, > > Shaoqiang Wang, Dan Kirk-Davidoff > > > A carbon sequestration strategy has recently been proposed in which a > > forest is sustainably managed to optimal carbon productivity, and a > > fraction of the wood is selectively harvested and stored to prevent > > decomposition. The forest serves as a ‘carbon scrubber’ or ‘carbon > > remover’ that provides continuous sequestration (negative emissions). > > The stored wood is a semi-permanent carbon sink, but also serves as a > > ‘biomass/bioenergy reserve’ that could be utilized in the future. > > Earlier estimates of the theoretical potential of wood harvest and > > storage (WHS) were 10 ± 5 GtC y-1. Starting from this physical limit, > > here we apply a number of practical constraints: (1) land not > > available due to agriculture; (2) forest set aside as protected areas, > > assuming 50% in the tropics and 20% in temperate and boreal forests; > > (3) forests difficult to access due to steep terrain; (4) wood use for > > other purposes such as timber and paper. This ‘top-down’ approach > > yields a WHS potential 2.8 GtC y-1. Alternatively, a ‘bottom-up’ > > approach, assuming more efficient wood use without increasing harvest, > > finds 0.1-0.5 GtC y-1 available for carbon sequestration. We suggest a > > range of 1-3 GtC y-1 carbon sequestration potential if major > > investment is made to expand managed forests and/or to increase > > management intensity. > > The implementation of such a scheme at our estimated lower value of 1 > > GtC y-1 would imply a doubling of the current world wood harvest rate. > > This can be achieved by harvesting wood at a modest harvesting > > intensity of 1.2 tC ha-1 y-1, over a forest area of 8 Mkm2 (800 Mha). > > To achieve the higher value of 3 GtC y-1, forests need to be managed > > this way on half of the world’s forested land, or on a smaller area > > but with higher harvest intensity. We compare the potential of WHS > > with a number of other carbon sequestration methods, and recommend WHS > > be considered part of the portfolio of climate mitigation options. > > > On Sep 21, 7:11 am, Duncan McLaren <duncan.p.mcla...@gmail.com> wrote: > > > > Group members may find my assessment of negative emissions > > > technologies (NETs) of interest. > > > > The full report runs to about 100 pages, and can be found > > > athttps://sites.google.com/site/mclarenerc/research/negative-emissions-... > > > > A summary version written for Friends of the Earth (England, Wales and > > > NI) will be published online later today. > > > > The assessment covers a wide range of NETs, but not SRM techniques. It > > > considers capacity, cost, side effects, constraints, technical > > > readiness, accountability and more for about 30 options. > > > > I'd be delighted to get feedback and comments. > > > > regards > > > Duncan -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To post to this group, send email to geoengineering@googlegroups.com. To unsubscribe from this group, send email to geoengineering+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en.
