Summary of IPCC expert on new scenarios. Towards New Scenarios for Analysis of Emissions, Climate Change, Impacts and Response Strategies

Transcription

1 Summary of IPCC expert on new scenarios Towards New Scenarios for Analysis of Emissions, Climate Change, Impacts and Response Strategies September 2007 Noorwijkerhout, NL John van Aardenne 1

2 Why this IPCC expert meeting? - identify requirements and plans for the development of new scenarios of emissions, climate change and adaptation and mitigation - decision of proposed set of benchmark concentration pathways Participants: Background information - ESM: researchers on Earth Systems Modeling including climate, carbon cycle, atmospheric chemistry - IAV: researchers on modeling of Impacts, Adaptation, Vulnerability - IAM: researchers on Integrated Assessment Modeling - users: experts from the policy and user communities Note: Development of scenarios is done by research community (not IPCC scenarios!) 2

3 The new scenario experiment: aim and time-lines considered GOAL: To Develop new scenarios of emissions, climate change and adaptation and mitigation including processes like carbon cycle, aerosols, chemistry, dynamic vegetation. Near term scenarios (to ~2030) - develop better projections of regional climate change and its impacts - include co-benefits with air quality and synergies between adaptionmitigation - high resolution models - IAM and IAV study uncertainties by exploring larger variety of scenarios Longer term scenarios (to 2100 and beyond) - options for stabilization of anthropogenic influences on climate or consequences of failure to do so. - feedbacks between climate and biogeochemistry and non-linearties in climate system. - lower resolution models - ESM determine uncertainty through large ensemble simulation for small number of scenarios. 3

4 Timeline of the new scenario experiments: The new scenario experiment: different phases (1) 4

5 The new scenario experiment: different phases (2) Preparatory phase: Benchmark Concentration Pathways (BCP) from IAM should be delivered to GCM, AOGCM and ESM modelers. Phase 1: a) GCM, AOGCM and ESM used BCP to produce climate scenarios b) IAM prepare new socio-economic, land use etc scenarios into a scenario library (open process for regional and global model teams) Phase 2: a) Downscaling of ensemble scenarios from ESM to study regional manifestation of global climate b) IAV impact assessments c) IAM: incorporate feedback processes in emission scenarios (ecosystem, carboncycle Phase 3: a) development of internal consistent scenarios on emissions, atmosphere-climateocean change, effect of climate change impacts b) publication of results to feed AR5 5

6 New concept of scenario studies: benchmark concentration pathways New concept of benchmark concentration pathways: start Serial activity, groups wait on each other start Parallel process of different groups EOS transactions,

7 Selection of Benchmark Concentration Pathways (criteria) Benchmark scenarios to be selected from existing literature (as used in AR4) What is in the benchmark scenarios? -GHG emissions and concentrations resulting from IAM - GHG: CO 2, CH 4, N 2 O, CFCs, HFCs, PFCs, SF 6 - Reactive gases: CO, NO x, NH 4, VOCs - Derived GHGs: tropospheric O 3 - Emissions of aerosol (precursors): SO 2, BC, OC TRICKY - Land use and land cover Extension to existing scenarios: -downscaling of short lived species and land use/land cover to 0.5x0.5 (near-term simulations) and 1x1 degree (long-term) -extension to 2300 by simple scaling (e.g. population). Deadlines for Benchmark scenarios: ~September

8 Selection of Benchmark Concentration Pathways (range of forcing) Range of radiative forcing and selection of BCP IMAGE 2.6 8

9 Selection of Benchmark Concentration Pathways (outcome) BCP 8.5 (850 ppmv): MESSAGE model (IIASA) BCP 6: probably MINICAM (PNNL) BCP 4.5: probably AIM (NIES) Lowest case: IMAGE model (MNP) Sensitive issue: proposed BCP3 seen too far from policy targets. BCP2.6 IMAGE scenario as tentative realization, scientific community attempts to derive a similar pathway to show that this is not an outlyer scenario. BCP2.9 IMAGE scenario as fallback option Decision to be made by IAM consortium together with 2 external experts (summer 2008) 9

10 Benchmark Concentration Pathways and atmospheric chemistry modelling Information request by ESM models (what might be available by mid-2008?) 10

11 Linking radiative forcing and atmospheric chemistry Interpretation of the climate scenarios is sensitive to: 1: level and geographical distribution of aerosols and chemically active gases 2: land use patterns. For the short term experiment depending on the ESM and on the scientific purpose calculation of space and time distribution of gases and aerosols will be performe online (in ESM if capable) or offline (global 3D chemistry models). A group of IAM, ESM met to discuss a harmonization exercise (Jean Francois Lamarque). Aim: a) consistent past, present, future emissions trend b) consistent gridding of emissions (0.5 or 1 degree) c) post-processing of emissions (VOC speciation, seasonality etc). d) consistent land use datasets How: Maybe workshop in early alt1: use EDGARv4 as basis (year=2004, maybe quick 2005 estimate) - alt2: select historical data based on emissions review of existing datasets, and apply sectoral grid definition to different datasets JRC is willing to provide EDGAR data to such an harmonization exercise. Link with HTAP work: are model requirements in HTAP comparable with ESM wishlist 11

12 Main message - mid 2008 new emissions scenarios up to year 2100 available to ESM, IAM IAV - existing published scenarios - some modifications planned (downscaling, harmonization) - quality of air pollutant emissions will differ between scenarios (ozone scale by CH 4, aerosols scaled by SO 2, etc). - in 2009 new emissions scenario experiments - open process, possible input from HTAP/AEROCOM - e.g. HTAP could think of providing improvement on AP scenario s (results of atmospheric chemistry models on future ozone and aerosol) - dataset within HTAP/AEROCOM and new scenario activity - EDGAR might be used in harmonization exercise (open for discussion) - downscaling of new emissions scenarios will 12