The Fifth Assessment: A Discussion of the IPCC Working Group 1 AR5 Report

Transcription

1 The Fifth Assessment: A Discussion of the IPCC Working Group 1 AR5 Report Prof. Chris E. Forest The Pennsylvania State University (ceforest@psu.edu) Lead Author - Chapter 9 - Evaluation of Climate Models! 19th Annual Energy and Climate Change Research Seminar May 13, 2014 Washington Marriott at Metro Center

2 IPCC WG1 Summary! The human influence on Earth s climate is clear It s still warming... but with more observables. More warming to come. New lines of evidence New concepts

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4 The Timeline 2010 MAY - IPCC WG1 Authors and Reviewers Selected 2010 NOVEMBER - First Lead Author Meeting - Kunming, China 2011 MARCH 18 - Zeroth Order Draft 2011 JULY - Second Lead Author Meeting - Brest, France 2011 NOVEMBER 18 - First Order Draft 2012 APRIL - Third Lead Author Meeting - Marrakech, Morocco 2012 AUGUST 10 - Second Order Draft 2013 JANUARY - Fourth Lead Author Meeting - Hobart, Australia 2013 MAY 13 - Final Draft 2013 SEPTEMBER 27 - IPCC Plenary Approval of SPM - Stockholm, Sweden

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7 (b) Observed change in surface temperature Observed Surface Temperature Changes Figure SPM.1a (a) Observed globally averaged combined land and ocean surface temperature anomaly Annual average 0.4 Temperature anomaly ( C) relative to Decadal average (b) Observed change in surface temperature ( C) Year

8 Increased focus on observed precipitation changes Observed change in annual precipitation over land (mm yr -1 per decade) (IPCC WG1 AR5 Figure SPM.2)

9 Many additional observations are now used to assess historical climate change Year (a) 45 Northern Hemisphere spring snow cover (c) 20 Change in global average upper ocean heat content (million km 2 ) (10 22 J) (b) Year 14 Arctic summer sea ice extent (d) Year 200 Global average sea level change (million km 2 ) (mm) (c) Year Year (IPCC WG1 AR5 Figure SPM.3)

10 Including key Carbon Cycle observations (a) CO2 (ppm) Atmospheric CO Year (b) pco2 (μatm) Surface ocean CO 2 and ph Year in situ ph unit (IPCC WG1 AR5 Figure SPM.4)

11 Anthropogenic warming has mainly occurred in the ocean.! Evidence in the Global Energy Budget Accumulated Energy Increase since 1970 >90% of energy increase in ocean heat content ZJ = Joules IPCC WG1 AR5 Box 3.1, Figure 1

12 The Drivers of Climate Change Radiative Forcing: Figure SPM.5 Emitted compound Resulting atmospheric drivers Radiative forcing by emissions and drivers Level of confidence Well-mixed greenhouse gases CO 2 CH 4 Halocarbons N 2 O CO 2 CO 2 H 2 O str O 3 CH 4 O 3 N 2 O CFCs HCFCs 1.68 [1.33 to 2.03] 0.97 [0.74 to 1.20] 0.18 [0.01 to 0.35] 0.17 [0.13 to 0.21] VH H H VH Anthropogenic Short lived gases and aerosols CO NMVOC NO x Aerosols and precursors (Mineral dust, SO 2, NH 3, Organic carbon and Black carbon) CO 2 CH 4 O 3 CO 2 CH 4 O 3 Nitrate CH 4 O 3 Mineral dust Organic carbon Sulphate Black carbon Cloud adjustments due to aerosols Nitrate 0.23 [0.16 to 0.30] 0.10 [0.05 to 0.15] [-0.34 to 0.03] [-0.77 to 0.23] [-1.33 to -0.06] M M M H L Albedo change due to land use [-0.25 to -0.05] M Natural Changes in solar irradiance 0.05 [0.00 to 0.10] M Total anthropogenic RF relative to [1.13 to 3.33] 1.25 [0.64 to 1.86] 0.57 [0.29 to 0.85] Radiative forcing relative to 1750 (W m 2 ) H H 2.6 M Wm -2

13 IPCC WG1 AR5, Figure SPM.6

14 Can Climate Models capture the observed changes? Land surface Global averages Land and ocean surface Ocean heat content Observations Models using only natural forcings Models using both natural and anthropogenic forcings IPCC WG1 AR5 Figure SPM.6

15 Can Climate Models capture the observed changes? IPCC WG1 AR5 Figure SPM.6

16 Can Climate Models capture the observed changes? Sea Ice IPCC WG1 AR5 Figure SPM.6

17 Can Climate Models capture the observed changes? Sea Ice Ocean Heat Content IPCC WG1 AR5 Figure SPM.6

18 What are the causes of warming? Based on attributable warming using local detection of temperature trends Observed = HadCRUT4 IPCC WG1 AR5 Figure 10.5

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20 RCP Scenarios have replaced SRES Scenarios (which replaced IS92 Scenarios RCP := Representative Concentration Pathways 2.6, 4.5, 6.0, & 8.5 := Radiative Forcing at 2100

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23 RCP Scenarios have replaced SRES Scenarios (which replaced IS92 Scenarios RCP := Representative Concentration Pathways 2.6, 4.5, 6.0, & 8.5 := Radiative Forcing at 2100

24 Climate Projections using RCP Scenarios Temperature, NH Sea Ice, Ocean ph IPCC WG1 AR5 Figure SPM.7

25 Climate Projections using RCP Scenarios Temperature, NH Sea Ice, Ocean ph (a) ( o C) Global average surface temperature change historical RCP2.6 RCP Mean over RCP2.6 RCP4.5 RCP6.0 RCP8.5 (c) (ph unit) Global ocean surface ph Year RCP2.6 RCP4.5 RCP6.0 RCP8.5 (b) 10.0 Northern Hemisphere September sea ice extent (5) (10 6 km 2 ) (3) (5) RCP2.6 RCP4.5 RCP6.0 RCP8.5 (c) Global ocean surface ph IPCC WG1 AR5 Figure SPM.7

26 Chapter 9 Summary Figure

27 Climate Projections using RCP Scenarios Low (RCP2.6) High (RCP8.5) (a) RCP 2.6 RCP 8.5 Change in average surface temperature ( to ) ( C) 2 (b) Change in average precipitation ( to ) (c) (%) IPCC WG1 AR5 Figure SPM.8 Northern Hemisphere September sea ice extent (average )

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29 2ºC Target 4ºC Target

30 Conclusions: The human influence on Earth s climate is clear

31 Conclusions: The human influence on Earth s climate is clear Past: It s still warming... but with more observables.

32 Conclusions: The human influence on Earth s climate is clear Past: It s still warming... but with more observables. Future: More warming. More sea level rise.

33 Conclusions: The human influence on Earth s climate is clear Past: It s still warming... but with more observables. Future: More warming. More sea level rise. New lines of evidence Deep Ocean, Carbon-cycle, sea-ice, ocean ph

34 Conclusions: The human influence on Earth s climate is clear Past: It s still warming... but with more observables. Future: More warming. More sea level rise. New lines of evidence Deep Ocean, Carbon-cycle, sea-ice, ocean ph New concepts Aerosol-Cloud effective forcing Earth System Models (emissions to response) Cumulative Carbon Emissions Temperature Target