Factoring out of indirect and natural effects

Transcription

1 Factoring out of indirect and natural effects Werner A. Kurz Natural Resources Canada Canadian Forest Service PFC, Victoria, BC Third Informal Dialogue on LULUCF Reykjavik, Iceland May 7-9, 2008

2 Outline What are the issues? Age-class legacy effects Natural disturbance effects Climate change effects Canada s forest carbon balance Proposal: Forward looking baseline with ex-post adjustment 2

3 Forest Sector Mitigation Potential IPCC AR4, WGIII identified high mitigation potential in Forest Sector Twenty of 36 Annex 1 countries elected FM under Article 3.4 of the Kyoto Protocol the potential is not fully used Various barriers to implementation Risk from natural disturbances Caps increasingly recognised as an interim solution in need of replacement. 3

4 Forest Sector Mitigation Potential Issues Legacy of age-class structure Impacts of natural disturbances (fire, insects, windthrow) Impacts of climate change (drought, weather extremes) All can be addressed through factoring out Factoring out : separating the impacts of direct human activities from the impacts of indirect human activities and natural effects. 4

5 Issue 1: Factoring out Effects of Age-class Legacy The future carbon balance of a managed forest is affected by today s age-class structure, which is the result of past disturbances. Measuring the absolute stock changes over a specified (commitment) period confounds impacts of management (change) with effects of age-class legacy. 5

6 The age-class legacy LS E RS Area Area Area Age class Age class Age class Three initial age-class structures: Even (1% of area in each 1 to 100 year) Left shifted (e.g. created from increased disturbances) Right shifted (e.g. created from decreased disturbances) Single site type described by one growth curve 6

7 The age-class legacy LS E RS Area Area Area Age class Age class Age class Biomass Mg C / ha Stand age 7

8 The age-class legacy LS E RS Area Area Area Age class Age class Management regime: harvest 1 % of area / yr Age class Biomass C E RS LS Time (years) 8

9 Lessons Learned Age-class structure affects the amount of C stored: In this example, the RS age-class structure contains 2.8 times the biomass of the LS age-class structure. Age-class structure also affects future C dynamics: With same management regime (harvest 1 % of area / yr): the RS landscape loses biomass C (debit), the E landscape is neutral and the LS landscape gains biomass C (credit). Age-class structure legacy affects preference for gross-net or net-net rules. 9

10 Management Effects RS Biomass C E LS Time (years) 10

11 Management Effects RS Management Change Biomass C E LS Time (years) 11

12 Management Effects RS Improving but reporting source Biomass C E LS Incentive to change FM Worsening but reporting sink Time (years) 12

13 Issue 2: Factoring out Impacts of Natural Disturbances Throughout the boreal forest, natural disturbances have significant impact on the annual GHG balance. 13

14 CFS Large Fires Database Area burned in fires ( > 200 ha ) from 1959 to Very high interannual variability Map shows 1980 to Source: Stocks et al

15 Mountain Pine Beetle Outbreak in British Columbia Large forest fires followed by natural regeneration and successful fire protection result in large amounts of mature pine forests Climate change impacts: warmer summers higher reproductive success, warmer winters (> -40 o C) higher overwinter survival rates Range expansion northward and to higher elevations 15

16 Annual area (ha 10 6 ) affected by MPB in BC Year 1999 Source: Tim Ebata, BC MoFR, Allan Carroll, CFS 16

17 Annual area (ha 10 6 ) affected by MPB in BC Year Source: Tim Ebata, BC MoFR, Allan Carroll, CFS 17

18 Annual area (ha 10 6 ) affected by MPB in BC Year Source: Tim Ebata, BC MoFR, Allan Carroll, CFS 18

19 Annual area (ha 10 6 ) affected by MPB in BC Year Source: Tim Ebata, BC MoFR, Allan Carroll, CFS 19

20 Annual area (ha 10 6 ) affected by MPB in BC Year Source: Tim Ebata, BC MoFR, Allan Carroll, CFS

21 Annual area (ha 10 6 ) affected by MPB in BC Year Source: Tim Ebata, BC MoFR, Allan Carroll, CFS

22 10.0 Annual area (ha 10 6 ) affected by MPB in BC Year Source: Tim Ebata, BC MoFR, Allan Carroll, CFS

23 Annual area (ha 10 6 ) affected by MPB in BC Year

24 Impacts of Current Mountain Pine Beetle Outbreak in British Columbia 24

25 Impacts of Current Mountain Pine Beetle Outbreak in British Columbia 25

26 MPB range expansion into the boreal forest? Lodgepole pine Ponderosa pine Mountain pine beetle Jack pine Lodgepole/jack hybrids Lodgepole/jack pine hybrid zone Immediately adjacent newly established pop n Invasion corridor? Source: Allan Carroll, CFS 26

27 Issue 3: Factoring out Impacts of Climate Change Some countries use Tier 3 process models to estimate C stock changes and report GHG emissions and removals. Interannual variability and long-term trends in climate (and other environmental factors) can have major impacts on GHG balance. Requires process models and ideally ground plot verification of the simulated effects (e.g. CO 2 fertilization). 27

28 Carbon Stock Changes in Canada s Managed Forest ( ) 28

29 Canada s National Forest Carbon Monitoring, Accounting and Reporting System (NFCMARS) 29

30 Carbon Budget Model of the Canadian Forest Sector (CBM-CFS3) An operational-scale model of forest C dynamics. Allows forest managers to assess carbon implications of forest management: increase sinks, reduce sources Builds on >15 years of CFS Science Available at: carbon.cfs.nrcan.gc.ca 30

31 Estimate C stock changes in the Managed Forest ~236 Mha of Managed Forest 31

32 Carbon Budget Model of Canadian Forest Sector Forest inventory and growth & yield data Natural disturbance monitoring data Forest management activity data Land-use change data Ecological modelling parameters CBM-CFS3 32

33 Area burned affects annual C balance C Stock Change (Mt C / yr) Source Sink Area Burned (Mha) 33

34 Managed Forest Carbon Stock Change Increasing importance of forest insects in recent years. 20 Sink Source Insects C Stock Change (Mt C / yr) Area Disturbed (Mha) Fire Harvest C Change

35 Monitoring Canada s managed forest was a net C sink between 1990 and A net source is estimated for years with large area burned. Increasing impacts of insects are contributing to a decreasing sink. 35

36 Estimates of Canada s Forest Carbon Balance in the near Future Risk Assessment of the Decision on Article 3.4 of the Kyoto Protocol 36

37 Background Article 3.4 of the Kyoto Protocol, provided the option to elect forest management to help meet emission reduction targets in the first commitment period ( ). If elected, then account for annual C stock changes in area of forest subject to forest management. All stock changes in the managed forest human induced or natural causes. But we cannot predict today the future area disturbed. What is the probability distribution of the net C balance of the managed forest in the first commitment period? 37

38 Predicting future forest dynamics using a stochastic approach Probability Insects Probability Fire Area Disturbed Area Disturbed 100 Monte Carlo Runs for all of Canada Probability Source Sink Net C stock change 38

39 Assumptions used in Risk Analyses Harvest: Used timber supply model or AAC projections, some adjusted based on provincial inputs. Fire: Annual area burned randomly drawn from regionally parameterized probability distributions of area burned. Insects: Regional projections of area and impact for six major insects based on historic data and current forest conditions. Conduct 100 simulation runs for all modelling regions in Canada Resample combinations of regional results to compile national distribution. 39

40 Canada s Managed Forest is Predicted to be a C Source in the Near Future 1 st CP Percentile Kurz et al. 2008, PNAS 40

41 Probability Distribution of 5-yr average CO 2 e Balance ( ) Source Kurz et al. 2008, PNAS 41

42 High Risk of Natural Disturbances Because of the very high interannual variability in annual area burned, any a priori baseline of natural disturbances is highly uncertain for a commitment period. Countries would likely be conservative when determining their baseline (i.e. assume high natural disturbances to protect against risk) but then could collect credits if natural disturbances were lower than assumed. Impacts of insects also large but have different time dynamics compared to fire. 42

43 Impacts of MPB in Western Canada Stock Change (Mt C / yr) Sink Source No Beetle With Beetle Beetle + Increased Savage Source: Kurz et al. 2008, Nature Impact of Beetle in 2009 and 2010: ~73 Mt CO 2 yr -1 43

44 Canada s Managed Forest is Predicted to be a C Source in the Near Future Percentile Kurz et al. 2008, PNAS 44

45 Canada did not elect Forest Management Reporting under Kyoto Rules Kyoto rules contribute to the risk that FM mitigation efforts are completely swamped by natural processes thus Article 3.4 provides few incentives to change FM Account for all carbon and non-co 2 emissions within the managed forest: includes all wildfires and insects No factoring out of pre-1990 age-class effects Reporting of absolute changes (gross-net accounting) not against a baseline (net-net) No accounting of harvested wood products 45

46 The Way Forward? Issues Legacy of age-class structure Impacts of natural disturbances (fire, insects, windthrow) Impacts of climate change (drought, weather extremes) Possible Solution: Forward looking baseline with ex-post adjustment 46

47 Forward looking baseline with ex-post adjustment Before commitment period (projection): Develop initial baseline of BAU C dynamics with current (BAU) management, age-class structure, projected (average) natural disturbances, and average climate. Identify forest management options that increase sinks and reduce sources Simulate climate mitigation management to estimate expected benefits Implement climate mitigation management Monitor natural disturbances Monitor implementation of climate mitigation activities 47

48 Forward looking baseline with ex-post adjustment After commitment period (monitoring): Recalculate baseline of BAU but with actual disturbances (and actual climate) Calculate C balance with climate mitigation management, actual disturbances (and actual climate). Report total contribution to atmosphere Assign credit/debit based on difference between adjusted BAU baseline and actual with climate mitigation activities. 48

49 A Visual Example Stock Change (Mt C / yr) Expected Mitigation Benefit Realised Mitigation Benefit Initial BAU Baseline Initial with Mitigation Activities Adjusted BAU Baseline Adjusted with Mitigation Activities 49

50 Forward looking baseline with ex-post adjustment Start of next commitment period (projection): Calculate new BAU baseline for future projections Takes into consideration the age-class structure resulting from recent disturbances. Therefore does not require a time-out period for disturbed areas. 50

51 Challenges Credits based on comparison to baseline may result in accounted carbon stock changes that differ in magnitude and/or sign from actual impact on the atmosphere. This requires that we: Report the contribution to atmosphere (actual stock change over commitment period) Account only for emissions and removals attributed to direct human activities (stock change relative to adjusted baseline). We quantify the impacts on the atmosphere but limit the credits/debits to the direct human-induced component. 51

52 Conclusions Forward looking baselines with ex-post adjustment address issues of age-class legacy, natural disturbances and climate variability. Provide a complete estimate of carbon balance, to quantify the impacts on the atmosphere, but Separate contribution of climate mitigation activities from natural and indirect-human effects. Do not result in a simpler system (but are similar to project accounting based on comparison to baseline and resolve issue of net-net or gross-net rules). Provide incentives to implement forest sector climate mitigation activities that benefit climate system. 52

53 Contact Information: Werner Kurz: References: Kurz et al., Nature, 452: , April 24th, 2008 Kurz et al., 2008, Proceedings of the National Academy of Sciences (PNAS), 105(5): Canadell et al. 2007, Env. Sci. Policy, 10: Available at 53