THE ROLE OF THE FORESTS, CO 2 EMISSIONS

Transcrição

1 Frank Werner THE ROLE OF THE FORESTS, CO 2 EMISSIONS AND CLIMATE CHANGE COMBAT

2 CO 2 -level in atmosphere highest in decades Source: CBC News Source: Spiegel online

3 CO 2 - effects of forests and wood products Forest as carbon pool Fossil emissions from production Wood Industrial Residual wood Buildings as carbon pool Fossil emissions from disposal Used wood Wood

4 on (partial) solutions

5 Overview Introduction The role of forests in mitigating climate change The tricky nature of GHG profiles of products GHG implications of different forest management and wood use scenarios Conclusions

6 Global carbon flows/rebound effects of climate change on forests/ of leverages in wood use /carbon pool dynamics and substitution THE ROLE OF FORESTS IN MITIGATING CLIMATE CHANGE

7 Increase in atmospheric CO 2 concentration

8 Human perturbations to the global carbon cycle

9 : the warmest decade on record

10 Feedback to climate change Climate change will affect many processes (growth, decay, disturbances) with great differences between ecosystems and regions We are currently not in the position to estimate net impacts, but Asymmetry of risks: unlikely that increases in productivity can offset increased disturbance losses (Kunz et al. 2008)

11 of leverages + Biomass expansion factor (BEF): 1.3 ( ) Commercial volume + C in litter + C in dead wood + Root:shoot ratio (R:S): 0.3 ( ) + C as soil organic carbon > living biomass (factor 1 6) + Transformation losses (< 50%) (Sources: IPCC 2003, IPCC 2000)

12 of leverages Living biomass Commercial volume C in Product Total forest carbon pools Ecoresponse Management intensity??? 3.4 m 3 2 m 3 Resource efficiency 1 m 3

13 Carbon dynamics of carbon pools vs. substitution C in forest pools cumulated C emissions Less use baseline t baseline t More use Carbon pools strive for steady state flow equilibrium Substitution effects are cumulative Cascade use allows for double substitution

14 Carbon dynamics of carbon pools vs. substitution C effects Substitution C pools in forest Less use baseline time More use C pools in forest Substitution

15 Use of wood from sustainably managed sources is always the better option than forest conservation with regard to mitigating climate change It is only a question of Time! and of what sustainably managed means

16 Comparison of GHG profiles/influence of geographical reference/influence of methodological issues/variances THE TRICKY NATURE OF GHG PROFILES OF PRODUCTS

17 Life cycle assessment for GHG-emission profiles Raw materials Aux. materials Energy carriers Disposal/ Recycling Dismantling Use phase 1 Window Raw material extraction Semifabricates Window prod. Mounting Wastes Emissions Co-products

18 Comparison of GHG-emission profiles Exterior walls Door frames Solid wood Brick wall (2-layers) Particleboard Steel Floorings Insulation materials (u-value = 0.2) Parquet (3-layers) Ceramic tiles Wood fibreboard Mineral wool (Werner et al. 2006, own calculations)

19 Choice of the geographical reference Exterior walls Door frames Solid wood Brick wall (2-layers) Particleboard Steel Floorings Substitution abroad Substitution in Switzerland Parquet (3-layers) Ceramic tiles (Werner et al. 2006)

20 Basis for comparison? Insulation materials (u-value = 0.2) Insulation materials (phase shift) Wood fibreboard Mineral wool Wood fibreboard Mineral wool Insulation materials (u-value = 0.2) Wood fibreboard Mineral wool (own calculations)

21 Variance between producers? IBU-EPD, Hersteller 1: IBU-EPD, Hersteller 2: + 40%

22 Selection of product for comparison? Parquet (life cycle) + 30% Glued single-layer 3 layered ready-made (Werner 1997)

23 Within-company variance? Wood-based board (life cycle) (Werner 2008)

24 Essence GHG profiles of wood products are usually lower than of comparative non-wooden products. Great variability of GHG profiles from both wooden/nonwooden products, Geographical scope matters, also for strategic decisions in national politics, Consideration of material substitution for semi-finished products does not make sense.

25 Modelling approach/scenarios/impact factors/results GHG IMPLICATIONS OF DIFFERENT FOREST MANAGEMENT AND WOOD USE SCENARIOS

26 Model-based approach Forest Technosphere Forest management scenarios Wood use scenarios Forest carbon model Wood flow model Model on C-stocks and substitution effects GHG relevance of different forest and wood use scenarios

27 Model of wood products carbon pools Wood pools in-country and abroad (without forest) Recovered wood (3 y.) Recovered wood (3 y.) Exports (50/50/50/30 y.) Used wood particle board (25 y.) Industrial residual w. (2 y.) Imports (50/50/50/30 y.) Abroad In-country Construction (80 y.) Interior works (30 y.) Recovered wood (3 y.) Wood products (10 y.) Industrial residual w. (2 y.) Energy wood for forest (2 y.) System boundary of civilisational cycle

28 Substitution on a building element level Building element Construction Wood elements/products Competing product/substitute Exterior wall Laminated timber board 2-layered brick wall Pillar Gluelam pillar Steel pillar Ceiling Ceiling of wood beams Ceiling of reinforc. concrete Insulation Wood fibre insulation panel Mineral wool Roofing Unlined joist construction Porous concrete pitched r. Underground engineer. Wood palisade Concrete palisade Interior works Coverings of wall Profiled board, spruce Interior plasterwork Staircase Wooden staircase, oak Ready-made concrete staircase Flooring 3-layered parquet flooring Ceramic tiles, enamelled Facade Wood panels incl. supporting bars Exterior plasterwork Furnishing Doorframe, particleboard Doorframe, steel Furniture Wood furniture, particleboard Steel furniture

29 Average substitution factors ( increment optimized ) kg CO 2 /m 3 wood (920 kg CO 2 ) Switzerland Abroad Total Material substitution Energetic substitution < -480 > Total < -800 > '330 (Werner et al.2010)

30 Scenarios The scenarios reflect realistic policy options. Wood extraction Increment optimized Kyoto optimized Reduced forest m. Baseline Wood extraction Switzerland + 90% + 75% - 40% + 20% Consumption Construction, interior works, wood products Construction Energy Construction + 80% + 0% + 80% - 24% + 20% Forest energy wood + 122% + 344% + 67% - 81% + 20% Foreign trade balance

31 /year Mio. t CO 2 -equiv. Comparison of scenarios Annual effects: global Adjustment of parameters Optimized increment, building Baseline Reduced tending Optimized increment, energy Kyoto optimized (Werner et al.2010)

32 /year -emissions Scenario Increment optimized, buildings Annual effects in Switzerland Percent of annual swiss CO % 6% 4% 2% 0% -2% -4% -6% -8% -10% -12% -14% Substitutional effects material Stock change in civ. Circle Sum of effects Substitutional effects energy Stock change in forests (Werner et al.2010)

33 CONCLUSIONS

34 Conclusions (I) The strategies that provide the best carbon balance on the longterm strive for an as high as possible wood use in domestic construction based on domestic wood supply. The material use of wood and subsequent energetic recovery is undoubtably the better option than direct energetic use (cascade use of wood). A pure sink carbon strategy in forest may seem promising in the short-term. Potential carbon gains of sink strategies will however not off-set impact of increased disturbances. Such strategies are not sustainble, also not from a resource perspective.

35 Conclusions (II) The climate effect of material substitution from wood use can be significant (positive). The substitution effect from material (and energetic) use of wood instead of non-wooden material is unlimited in time (cumulative). Increase of C-pools leads to a new steady-state flow equilibrium = no further net storage effect in equilibrium. Uncertainties and data variability in such models, e.g. related to forest dynamics, substitution effects, scenarios, etc. Interpretation is crucial!

36 Conclusions (III) Strategies for an optimized use of forests and wood to mitigate climate change can only reasonably assessed in an integral way, including transsectoral effects (e.g. substitution effects). For the assessment of these strategies, clear geographical and temporal preferences have to be stated.

37 Muito obrigado!