Ocean impacts (risks) under different temperature scenarios (1.5°C vs. 2°C vs. 4°C)

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  • Figure 30-9: (a) Simulated changes in dissolved O2 (mean and model range as shading) relative to 1990s for
    RCP2.6, RCP4.5, RCP6.0, and RCP8.5. (b) Multi-model mean dissolved O2 (μ mol m–3 ) in the main thermocline
    (200–600 m depth average) for the 1990s, and changes in the 2090s relative to 1990s for RCP2.6 (c) and RCP8.5
    (d). To indicate consistency in the sign of change, regions are stippled when at least 80% of models agree on the
    sign of the mean change. These diagnostics are detailed in [Cocco et al. , 2013] in a previous model inter-comparison
    using the SRES-A2 scenario and have been applied to CMIP5 models here. Models used: CESM1-BGC, GFDLESM2G,
    GFDL-ESM2M, HadGEM2-ES, IPSL-CM5A-LR, IPSL-CM5A-MR, MPI-ESM-LR, MPI-ESM-MR,
    NorESM1. Figure originally presented in WGI Figure 6.30 in WGI.
  • Figure 30-9: (a) Simulated changes in dissolved O2 (mean and model range as shading) relative to 1990s for
    RCP2.6, RCP4.5, RCP6.0, and RCP8.5. (b) Multi-model mean dissolved O2 (μ mol m–3 ) in the main thermocline
    (200–600 m depth average) for the 1990s, and changes in the 2090s relative to 1990s for RCP2.6 (c) and RCP8.5
    (d). To indicate consistency in the sign of change, regions are stippled when at least 80% of models agree on the
    sign of the mean change. These diagnostics are detailed in [Cocco et al. , 2013] in a previous model inter-comparison
    using the SRES-A2 scenario and have been applied to CMIP5 models here. Models used: CESM1-BGC, GFDLESM2G,
    GFDL-ESM2M, HadGEM2-ES, IPSL-CM5A-LR, IPSL-CM5A-MR, MPI-ESM-LR, MPI-ESM-MR,
    NorESM1. Figure originally presented in WGI Figure 6.30 in WGI.
  • Figure 3. Metabolic index and its projected changes this century. A) Metabolic index as a function of temperature and oxygen, B) relative (%) changes in metabolic index, as predicted from IPCC model simulations, averaged over the upper thermocline (0-500m) for the period 2071-2100, relative to 1970-2000.
  • Figure SPM.6: Ocean acidification, risks for fisheries.
    Marine mollusk and crustacean fisheries and known locations of cold- and warm-water corals, depicted on a global map showing the projected distribution of ocean acidification under RCP8.5 (pH change from 1986-2005 to 2081-2100). The bottom panel compares sensitivity to ocean acidification across vulnerable animal phyla with socioeconomic relevance.
  • Ocean impacts (risks) under different temperature scenarios (1.5°C vs. 2°C vs. 4°C)

    1. 1. Hans-O. Pörtner: Co-Chair WGII AR6 AR5: CLA WGII CH. 6, Ocean Systems, Ocean products in TS and SPM, CC-Boxes, SYR, SED UNFCCC Art. 2: ......prevent dangerous anthropogenic interference.... ............allow ecosystems to adapt naturally... ............ensure that food production is not threatened... ............enable economic development to proceed in a sustainable manner Ocean impacts (risks) under different temperature scenarios (1.5°C vs. 2°C vs. 4°C) Scientific findings: Reducing uncertainty in decision making
    2. 2. Historical change in SST RCP 2.6 RCP 8.5 projected ... warmingAccording to emission scenarios oceans are: CMIP5 model runs Gattuso et al., 2015 WGI Figure 6.30 ... losing oxygen Historical projected committed climate change Historical  Projections ...acidifying committed
    3. 3. WGI Figure 6.30 Observations and Projections: Deoxygenation Areas of low oxygen are expanding: coastal dead zones midwater oxygen minimum zones
    4. 4. Spatial changes ...and a small overall decrease ....in ocean primary production IPCC AR5 WGII Figure 6.13 4°C~1.5°C +1.5 to >>2 °C... warming:
    5. 5. CHANGE IN MAXIMUM CATCH POTENTIAL (2051-2060 COMPARED TO 2001-2010, SRES A1B, 2°C warming of global surface T 0.7°C warmer Sea Surface T) <50% -21 – 50% -6 – 20% -1 – 5% No data 0 – 4% 5 – 19% 20 – 49% 50 – 100% >100% WGII, 6-14, SPM.6, SYR 2.6 2°CProjections 2051-60: fish and invertebrate biomass and diversity displaced and reduced at low latitudes Unabated Ocean Warming by 2050
    6. 6. REDUCED HABITAT range of marine fishes and invertebrates due to thermal constraints combined with oxygen loss in the oceans by ~20% overall Northern High Latitudes: by ~40% >>2°C 2071-2100, 0-200m IPCC Earth System Model mean, RCP8.5 scenario C. Deutsch, A. Ferrel, B. Seibel, H.-O. Pörtner, R.B. Huey, Science 2015 TO BE ASSESSED IN AR6 Projections
    7. 7. WGII, SPM.6 >>2 °C Unabated Ocean acidification affecting mollusk and crustacean fisheries, and coastal protection by coral reefs .....risks enhanced by warming extremes
    8. 8. Verons 2009 Warm water coral reefs under various pressures Vulnerable ecosystems identified in AR5 Observations: Loss of live coral cover due to various drivers WGII Box CC-CR Great Barrier Reef 0.8°COBSERVATIONS 2016 High risk of losing up to 90% of coral reefs and their services to humankind in a 1.5°C warmer world....
    9. 9. How to widely compare climate impacts?LTGG 0.8 2 1.5 4 °C A role for natural marine systems to guide the setting of long-term global goals (LTGG, relative to preindustrial), considering levels of risk 0.8°C 1.5°C 2°C 4°C LTGG ...comparing LTGGs, identifying... Key risks of impacts .... Risks to be avoided Level of additional risk due to climate change IPCC WGII Risk assessment IPCC WGII:
    10. 10. Additional risk due to climate change AN EXAMPLE: COMBINED IMPACTS OF CLIMATE DRIVERS: ocean warming and acidification, a comparative view across LTGGs based on risk 0.6°C~ ~ 4°C LTGG 2°C~ 1.5°C~ 1.5°C vs. 2°C vs. >>2°C SYR 2.5
    11. 11. Magnan et al. 2016 Nature Climate Change Linking to INDCs and Global StocktakeOCEAN RISKS 2.7 1.5 >4 3.5 0.8 TO BE ASSESSED IN AR6 °C ServicesBiota
    12. 12. Sea level rise beyond 2100 may challenge natural and human systems: 1.5°C 1.5°C~ 2°C~ Knutti et al., Ngeo 2015 TO BE ASSESSED IN AR6Global mean temperature change (°C) Long-termsea-levelrise(m) >7m : ...last time when the atmosphere had 400 ppm CO2 (in Pliocene, 3-5 Mya) 5-9 m : ...during the last interglacial (Eemian, 125.000 ya, at 0.7-2°C above pre-industrial) Coming close to Paleo-findings.... ....affecting habitat, freshwater resources, human society through flood events High ambition mitigation needed
    13. 13. Future Risks Climate change will amplify existing risks and create new risks for natural and human systems. Risks are unevenly distributed and are generally greater for disadvantaged people and communities in countries at all levels of development. Increasing magnitudes of warming increase the likelihood of severe, pervasive, and irreversible impacts for people, species and ecosystems. WGII SPM
    14. 14. • Ocean acidification: Defending oyster cultures at the US Westcoast against inflow of acidified water. • Marine Protected Areas: Enhancing the resilience of coral reefs and their fish stocks against warming and acidification. • Restoration of Mangrove Forests ALREADY OCCURRING REGIONAL ADAPTATION IS …but adaptation capacity is highest under moderate climate change, ≤ 1.5°C
    15. 15. IPCC WGII Ocean Reprint Collection: http://ipcc-wg2.gov/publications/ocean/ Thank you!

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