MJ Apps, Canadian Forest Service Nov 2004 Why regional carbon budgets? Scientific and Policy Background Scientific and policy requirements for comprehensive and dynamic carbon budgets Mike Apps GCP Scientific Steering Committee & Natural Resources Canada Canadian Forest Service

MJ Apps, Canadian Forest Service Nov 2004 How will rates of atmospheric C accumulation change? –Impacts –Adaptation measures Can the fluxes causing the atmospheric accumulation be controlled? –Mitigation: what can be done to reduce sources and or increase sinks –Can these be monitored effectively? –How long will they last? Two Overarching Questions

MJ Apps, Canadian Forest Service Nov 2004 Active Carbon Cycle Exchange of 120 GtC/yr (land), and 90 GtC/yr (ocean) C is cycled, not permanently stored A natural cycle that has operated for at least 4 glacial cycles Provocative insight: Kleidon Climatic Change 2004

MJ Apps, Canadian Forest Service Nov 2004 Similar behaviour over multiple glacial cycles Warm – deglaciation, 280 ppm Cold – glaciation, 180 ppm Narrow range of CO 2 variation: ~180 ppm to ~280 ppm Petit et al., 1999

MJ Apps, Canadian Forest Service Nov 2004 Variation in T and CO 2 over last 4 glacial cycles A stable mode of behaviour for at least the past ½ million years Temperature CO 2 Future? Today Falkowski et al., 2000 Petit et al., 1999

MJ Apps, Canadian Forest Service Nov 2004 Perturbed Active Carbon Cycle Fossil deposits And adds additional carbon to the active cycle Human activity alters mechanisms of the cycle How the Earth system handles these perturbations will determine the impacts How human activities are modified will influence the magnitude and timing of the perturbation

MJ Apps, Canadian Forest Service Nov Ocean Uptake Land Uptake 2.2 Land-Use Change 6.3 F Fuel, Cement Global Budget: Top Down Perspective Atmosphere Surface biosphere Data for 1990s from Houghton 2003 Re-analyses of Ocean (Plattner) and LUC data Net: s Atmospheric accumulation rate 3.2 GtC per year 1990s GtC/yr - equivalent to burning all of Canada’s trees every two years.

MJ Apps, Canadian Forest Service Nov Ocean Uptake Land Uptake 2.2 Land-Use Change 6.3 F Fuel, Cement Global Budget: Main questions Atmosphere Surface biosphere Atmospheric accumulation rate 3.2 GtC per year 1990s 2.9 How good are estimates? Where are the release occurring? How will they change over time? Can human behavior be modified?

MJ Apps, Canadian Forest Service Nov 2004 Similar set of questions 2.4 Ocean Uptake Land Uptake 2.2 Land-Use Change 6.3 F Fuel, Cement Global Budget: Main questions Atmosphere Surface biosphere Atmospheric accumulation rate 3.2 GtC per year 1990s 2.9

MJ Apps, Canadian Forest Service Nov Ocean Uptake Land Uptake 2.2 Land-Use Change 6.3 F Fuel, Cement Global Budget: Main questions Atmosphere Surface biosphere Atmospheric accumulation rate 3.2 GtC per year 1990s 2.9 What are the mechanism responsible? Where is the uptake occurring? How will it change over time? Can management influence?

MJ Apps, Canadian Forest Service Nov 2004 REDUCE SOURCESINCREASE SINKS Global Budget: Scoping mitigation opportunities 2.4 Ocean Uptake Land Uptake 2.2 Land-Use Change 6.3 F Fuel, Cement Atmosphere Surface biosphere Atmospheric accumulation rate 3.2 GtC per year 1990s 2.9 Activities are undertaken within regions at local levels Comprehensive REGIONAL budgets are needed for guidance

MJ Apps, Canadian Forest Service Nov 2004 Mitigation: carried out at local to regional scales Mitigation: Regional C Budget requirements: Comprehensive/sectoral perspective –Implementation and accuracy Spatially complete –Resolution appropriate for decision making or reporting Appropriate time scales –Resolution years, horizon yrs Forecasting/scenario ability –Planning strategies Tracking/monitoring ability with uncertainties –Evaluating, assessing, and adaptive management. Reporting Transparency, credibility, explicit uncertainty –Accountability and comparability

MJ Apps, Canadian Forest Service Nov 2004 Global Perspective: reconciling top-down and bottom up Land uptake currently inferred as residual. –Bottom up estimates are incomplete – limited by sectors, regions, and data Houghton reviewed the recent top down and bottom up estimates and attempts to reconcile. Houghton concludes –global land net uptake : net tropical source and a net northern sink, –magnitudes depend on accuracy of estimates of tropical LUC and –Both net tropical source and net northern sink appear to change over time R.A.Houghton, Global Change Biology 9: ,

MJ Apps, Canadian Forest Service Nov 2004 Importance of mechanisms for land uptake What we now know: No single region is responsible No single mechanism is responsible Rather Spatial mosaic of sources and sinks – at many scales, across landscapes, across biomes, across regions Biological sources and sinks are often autocorrelated (but with time delays) The spatial mosaic changes with time Gaining a quantitative understanding of the processes underlying the land uptake is INTRINSICALLY a REGIONAL AND LOCAL problem, with scaling up challenges  REGIONAL CARBON BUDGETS

MJ Apps, Canadian Forest Service Nov 2004 Importance of mechanisms for land uptake 1)Different mechanisms  different mitigation approaches policy interest, scientific challenge 2)Different mechanisms  different future trajectories (climate implications) scientific challenge, policy need – though not always appreciated! 3)Ability to factor out direct human interventions from indirect responses and natural variability policy request, strong scientific challenge

MJ Apps, Canadian Forest Service Nov 2004 Increased growth rate, decreased decomposition Different factors important for different regions Increased Site fertility (Carrying capacity) Two broad mechanisms for land uptake 1.Changes in productivity (stimulated NPP, reduced respiration) in response to CO2, climate, nutrient, management … Examples Disturbed soils Forest Stand Biomass+ detritus +soils age Site C i Deceased site fertility, growth rate, …

MJ Apps, Canadian Forest Service Nov 2004 Two broad mechanisms for land uptake 2.Changes in demographics (age distribution) due to change in mortality (LUC or natural distrubances) stand age CiCi Site level At landscape or regional scale, must take into account age distribution Shift of average age to right increases C (i.e., landscape becomes a sink) Shift to left decreases C (i.e. source)

MJ Apps, Canadian Forest Service Nov 2004 stand age stand C i Biomass+ detritus +soils Source Sink Subtle scaling issue: Site to Landscape Local Tower But, significant time before C released during/after disturbance is recaptured Net loss Net removal Site scale accumulation Must be very careful when scaling up site to regional Contribution to landscape remains deficit for much longer than instantaneous measurement suggests

MJ Apps, Canadian Forest Service Nov 2004 Need for comprehensive system perspective At any scale, net flux to atmosphere is a complex balance of many individual time varying fluxes each having different controls Equivalent/complementary results (conservation of mass) IFF all significant fluxes, and all significant stock changes are accounted Two basic approaches to carbon balance: 1) Flux estimates 2) Pool (stock) change Carbon balance at an ecosystem scale e.g., Barford et al (2001)(Harvard ) Carbon balance at a regional scale e.g., Janssens et al (2004) (Europe) Carbon balance at a global scale e.g., Houghton (2003)

MJ Apps, Canadian Forest Service Nov ± 1.1 Land uptake 2.4 ± 0.7 Oceans 3.2 ± 0.1 GtC/yr Atmosphere increase 6.3 ± 0.4 F Fuel, Cement Atmosphere Surface biosphere 2.2 ±0.8 Land-Use Change Forests ? Ocean Circulation ? Sarmiento et al 1998 Peterson et al 2001 >8Gt/yr? Need for comprehensive system perspective Especially important in predicting future atmospheric carbon if some of the present feedbacks fail … Balance will be altered by global change Cox et al 2000 Kurz &Apps 1999

MJ Apps, Canadian Forest Service Nov 2004 Carbon feedbacks from dieback in Amazon Ignoring climate change Uptake Including climate change Release Betts: Future changes (?) global & region scale Regional changes with global significance Betts et al 2004

MJ Apps, Canadian Forest Service Nov 2004 Betts: Future changes (?) global & region scale Even larger changes simulated for soils

MJ Apps, Canadian Forest Service Nov 2004 MJA IOS Mar Kurz and Apps, Ecol. Appl With large C consequences Note Change after 1970 Kurz and Apps: Contemporary, regional scale Stand replacing disturbances in Canadian forests have changed over last 50 years

MJ Apps, Canadian Forest Service Nov 2004 Policy and decision makers focus on: – Likely impacts (party/country level and globally) Of not doing anything ( impacts and adaptation potential) Of mitigation measures (cost/benefit) Timing of these impacts – Feasible mitigation opportunities Within country Globally – Robust analysis of party (country) level budgets Trade and negotiations Planning and monitoring Summary: Policy issues and challenges

MJ Apps, Canadian Forest Service Nov 2004 Quantitative understanding the spatial and temporal dynamics of the perturbed carbon cycle: –Reconciling top-down and bottom-up estimates of the global carbon budget –Understanding the mechanisms that control the major fluxes ( anthropogenic and biospheric ) making up the budget –Predicting how the budget will change over time –Observation and measurement challenges posed by the above needs Summary: Science issues and challenges

MJ Apps, Canadian Forest Service Nov 2004 The way forward? ‘ Better’ regional carbon budgets Data, comprehensive (processes, sectors, pools), spatial representation, dynamic that can be used to constrain and augment global budgets to inform decision makers at regional scales to enable implementation of carbon management strategies to monitor progress at relevant scales and facilitate adaptive management

MJ Apps, Canadian Forest Service Nov 2004 Think globally, analyze locally