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Climate change integrated assessment methodology for cross- sectoral adaptation and vulnerability in Europe. Climate change scenarios incorporated into the CLIMSAVE Integrated Assessment Platform. For further information contact Martin Dubrovsky (email: ma.du@seznam.cz)
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Climate change integrated assessment methodology for cross-sectoral adaptation and vulnerability in Europe Climate change scenarios incorporated into the CLIMSAVE Integrated Assessment Platform For further information contact Martin Dubrovsky (email: ma.du@seznam.cz) or visit the project website (www.climsave.eu) Funded under the European Commission Seventh Framework Programme Contract Number: 244031
Presentation structure 1. Introduction 2. Methodologies for preparing reduced-form ensembles of future climate scenarios (...focus on uncertainties) 2.1 GCM ensemble (CMIP3 data ~ IPCC-AR4) for European case study 2.2 UKCP09data for Scottish case study + representativeness of the reduced-form ensembles 3. Comparison of GCM-based vs. UKCP09 scenarios 4. Summary & Conclusion
Introduction – CLIMSAVE project CLIMSAVE project (www.climsave.eu; 2010-2013) • coordinated by the Environmental Change Institute, University of Oxford • 18 partnersfrom 13 countries (incl. China and Australia) • Aim:integrated methodology to assess cross-sectoral climate change impacts, adaptation and vulnerability • The main product of CLIMSAVE:a user-friendly, interactive web-based tool (Integrated Assessment Platform; IAP) that will allow stakeholders to assess climate change impacts and vulnerabilities for a range of sectors • IAP is based on an ensemble of meta-models, which are run with the user-selected climatic datarepresenting present and future climates • When creating an ensemble of climate change scenariosfor the IAP, two requirements were followed: 1. an ensemble of climate change scenarios is not large, and 2. it satisfactorily represents known uncertainties in future climate projections.
GCM-based scenarios(based on monthly GCM outputsfrom IPCC-AR4 database /~CMIP3/;Europe)
GCMs in CMIP3 database We use 16 SRES-A2 simulations of 24 GCMs x 6 emission scenarios (incomplete matrix).
Pattern scaling is used to create a set of climate change scenarios Pattern scaling approach allows to reflect multiple uncertainties:- where several ΔTG values are used to multiply several GCM-based patterns ΔTG = change in global mean temperature ΔXS = standardised scenario (relatedto ΔTG= 1K; derived from GCMs) ΔX(t) = ΔXSx ΔTG(t) uncertainty in pattern (~ modelling uncertainty): uncertainty in TG (~uncertainties in emissions & climate sensitivity): X 3 sources of uncertainty
Reducing an ensemble of scenarios When using the above pattern-scaling approach (GCM-based standardised scenarios are scaled by MAGICC-modelled TGLOB values), we • find a “representative” subset of GCMs, which satisfactorily represents the inter-GCM uncertainty, • choose several TGLOB values, which account for uncertainties in emission scenarios and climate sensitivity.
Choosing a setof TGLOB values TGLOB (modelled by MAGICC for 6 SRES emissions scenarios x 3 climate sensitivities) Considering SRES emissions scenarios and 1.5-4.5K interval for climate sensitivity: 2050:effect of uncertainty in climate sensitivity is (slightly) larger 2100: both effects are about the same CLIMSAVE employs 12 values of TGLOB(~ 4 emissions x 3 climate sensitivity) Reduced set of 3 values: emissions clim.sensitivity high scenario: SRES-A1FI 4.5 K low scenario: SRES-B1 1.5 K middle scen.: SRES-A1b 3.0 K
Defining a representative subset of GCMs • Two approaches are used here to define a representative GCM subset: • A. expert-based judgement “CLIMSAVE” subset • B. applying objective criteria “EU5a” subset
“CLIMSAVE” subset (method: expert choice) Input: summer (JJA) winter (DJF) ΔTAVG + ΔPREC Output(5 GCMS): MPEH5, HADGEM, GFCM21, NCPCM, MIMR
Defining a “EU5a” subset(based on objective criteria) • Target size of the subset = 5 GCMs • The subsets will consist of: • best GCM [Quality(GCM) ~ ability to reproduce annual cycle of TEMP and PREC in a given 0.5x0.5°gridbox] • central GCM(8D metrics ~ changes in seasonal TEMP and PREC) • +3 most diverse GCMs(maximising a sum of inter-GCM distances; the same metrics) • (prior to analysis, GCM outputs were regridded into 0.5x0.5° grid common with the CRU climatology)
“Best” GCM Best GCM; Q = f [ RV(Temp), RV(Prec)] ...based on RV(Prec) MPEH5 = GCM which is the best in the largest number of gridboxes [Quality(GCM) ~ ability to reproduce annual cycle of TEMP and PREC in a given 0.5x0.5°gridbox] ...based on RV(Temp)
+ “Central” GCM ( = closest to Centroid) = GCM which is the Central GCM in the largest number of gridboxes (metrics: Euclidean(8D ~ seasonal changes in TEMP and PREC) • note: MPEH5 and HadGEM, which were found to be among the best GCMs, are also among the three most central GCMs CSMK3
3 mutually most diverse GCMs HADGEM, GFCM21, IPCM4
1 centroid 5 GCMs for Europe(3799 0.5°x0.5° land grid boxes) 1 best 3 most diverse 3bests “EU5a”: MPEH5, HADGEM, GFCM21, CSMK3, IPCM4 vs. “CLIMSAVE”: MPEH5, HADGEM, GFCM21, NCPCM, MIMR
GCM subset validation(number of significant differences in AVGs and STDs (subset vs.16 GCMs) EU5a vs. 16GCMs CLIMSAVEvs. 16GCMs • Whole Europe: • - the CLIMSAVE’s problem: significant underestimation of inter-GCM variability in TEMP • - EU5a performs better • both TEMP and PREC • both AVG and STD • UK: • - not such large differences between the two subsets avg(ΔT) std(ΔT) avg(ΔP) insignificant difference: A16G-½S16G, < avgsubset< A16G+½S16G ⅔S16G, < stdsubset< 3/2.S16G std(ΔP)
UKCP09-based climate scenarios • UKCP09 = future climate projection developed by UK Met. Office (http://ukclimateprojections.defra.gov.uk). It is based on: • PPE of HadSM3 simulations (= simplified HadCM3) (PPE = Physically Perturbed Ensemble; 31 key model parameters perturbed) • downscaled by Hadley RCM, • adjustedby outputs from 12 other GCMs, • and disaggregated into 10000 valuesby a statistical emulator • Probabilistic projections of climatic characteristics is given in terms of 10000 possible values (realisations) for each 25x25 km grid box over UK • the projection is available for 3 SRES emission scenarios (low = B1, medium = A1b, high = A1FI) • Aim: Reduce 3 (emissions) x 10,000 realisations to reasonably large ensemble of scenarios (preserving the ensemble variability)
UKCP09 climate scenarios- creating the reduced-form ensemble • 3D space [Tannual, Psummer, Pwinter] • 27 points relate to 3x3x3 combinations of low, med, high changes in the three variables [median, 10th and 90th percentiles along each of 13 lines going through the cube’s center and defined by corners/centres of sides/centres of edges of the cube] • 27 scenarios = the means of 10 neighbours closest to each of 27 points (in a 3D space) Ta Psummer Pwinter 27 climate change scenarios related to 3x3x3 combinations of (low, med, high) changes in dTannual, dPsummer, dPwinter
UKCP09 (2050s): TEMPannual= middle WL-SL WL-SM WL-SH WM-SL WM-SM WM-SH WH-SL WH-SM WH-SH TEMPannual PRECONDJFM PRECAMJJAS
Same but for TEMPannual= low TEMPannual PRECONDJFM PRECAMJJAS slide #20
Same but for TEMPannual = high TEMPannual PRECONDJFM PRECAMJJAS
UKCP09: full vs. reduced ensembles • Q: How does the reduced UKCP09 ensemble represent the original ensemble? • input “full” database = 30000 scenarios = • (3 emission scenarios) x (10000realisations) • for each grid, climate variable and 10 year timeslice) • reduced-form scenarios = 91 scenarios = • (3 emission scenarios) x (27 scenarios representing 3x3x3 combinations of low/medium/high values of Tannual, Psummer, Pwinter • for each grid, climate variable, 2020s and 2050s timeslices • maps: avg(std) from 10000vs. 27scenarios for 2050s (this and following 2 slides) low (SRES-B1) med (SRES-A1b) high (SRES-A1FI) 3 emis.scen. JJA DJF JJA DJF JJA DJF JJA DEC 10000 members 3x 10000 memb. PREC full vs. reduced ensembles: good fitbetween the means 27 clusters 3x 27 clust. JJA DJF JJA DJF JJA DJF JJA DEC
UKCP09: full vs. reduced ensembles 3 emis.scen. low (SRES-B1) med (SRES-A1b) high (SRES-A1FI) JJA DJF JJA DJF JJA DJF JJA DEC 10000 members 3x 10000 memb. TEMP perfect fit 3x 27 clust. 27 clusters 3x 10000 memb. 10000 members PREC perfect fit 3x 27 clust. 27 clusters JJA DJF JJA DJF JJA DJF JJA DEC
UKCP09 vs.GCM (only UK territory) • UKCP09: • original ensemble = 3 emissions x 10000 realisations = 30000 scenarios • reduced ensemble = 3 emissions x 27 scenarios = 81 scenarios • GCMs: • original ensemble = 16 GCMs x 4 emissions x 3clim.sens. = 192 scen. • reduced ensemble = 5 GCMs x 4 emissions x 3clim.sens. = 60 scenarios • UKCP09 vs GCMs: • ........................... UKCP09....... GCMs • full datasets: 30000 vs.192 scenarios • reduced dataset: 81vs.60 scenarios
UKCP09 vs GCMs: avg(PREC) 3 emis.scen. low (SRES-B1) med (SRES-A1b) high (SRES-A1FI) JJA DEC JJA DEC JJA DEC JJA DEC 5GCMs x 3CS reduced dataset GCMs 16GCMs x 3CS full dataset UKCP09 shows slightly larger reductions in PREC 10000 members UKCP09 27 clusters reduced dataset JJA DEC JJA DEC JJA DEC JJA DEC
UKCP09 vs GCMs: avg(TEMP) 3 emis.scen. low (SRES-B1) med (SRES-A1b) high (SRES-A1FI) JJA DEC JJA DEC JJA DEC JJA DEC 5GCMs x 3CS reduced dataset GCMs 16GCMs x 3CS significant difference between GCM and UKCP09 full dataset 10000 memb. UKCP09 reduced dataset 27 clusters JJA DEC JJA DEC JJA DEC JJA DEC
UKCP09 vs GCM: std(PREC) 3 emis.scen. low (SRES-B1) med (SRES-A1b) high (SRES-A1FI) JJA DEC JJA DEC JJA DEC JJA DEC 5GCMs x 3CS reduced dataset GCMs GCMs:the subset reproduces the internal variability 16GCMs x 3CS full dataset • GCMs vs UKCP09:internal UKCP09 ensemble variability is larger (corresponds to larger avg(TAVG) in UKCP scenarios) 10000 members UKCP09 UKCIP09:the reduced-form ensemble reduces internal variability 27 clusters reduced dataset JJA DEC JJA DEC JJA DEC JJA DEC
UKCP09 vs GCMs: std(TEMP) 3 emis.scen. low (SRES-B1) med (SRES-A1b) high (SRES-A1FI) JJA DEC JJA DEC JJA DEC JJA DEC 5GCMs x 3CS reduced dataset GCMs 16GCMs x 3CS GCMs vs UKCP09:internal UKCP09 ensemble variability is larger full dataset 10000 memb. UKCP09 reduced dataset 27 clusters
Summary + Conclusions (1) • Climate change impact studies require ensembles of climate change scenarios representing known uncertainties. Available scenario datasets were too large for CLIMSAVE, reductions were proposed. • 2 case studies in CLIMSAVE = 2 datasets to reduce in size: • GCMs(CMIP3 dataset of GCMs from various modelling groups): • “large ensemble” = 16 GCMs x 4 emissions x 3 climate sensitivity = 192 scenarios (~ 3 uncertainties) • reduced-form ensemble = 5 GCMs x 4 emissions x 3 climate sensitivity (or 5 GCMs x 3 dTglob) = 60 (15) scenarios • though the “optimum” subset varies across Europe, the single GCM subset still reasonably well represents the inter-GCM variability over majority of European territory • UKCP09[~ PP(HadSM) + HadRM + “statistical emulator”] • large ensemble = 10000 realisations x 3 emission scenarios = 30000 scenarios (structural uncertainties within 10000 members also account for climate sensitivity uncertainty) • reduced-form ensemble = 27 scenarios x 3 emissions = 81 scenarios • within-ensemble variability is lower (effect of natural climate variability is reduced)
Summary + Conclusions (2) • In both ensembles: • the reduced-form scenarios reasonably well represent means and variabilities of the original ensembles • > structural & climate sensitivity & emissions uncertainties are preserved • GCMs vs UKCP09: • except for avg(PREC), significant differences between the 2 ensembles were found • [these differences] >> [the differences related to reducing the original datasets]