Warming and acidification of the Mediterranean Sea

Transcription

1 Warming and acidification of the Mediterranean Sea Jean-Pierre Gattuso CNRS-Université Pierre et Marie Curie-Paris 6 Institute for Sustainable Development and International Relations

2 Global carbon budget ( ) 0.8 Pg C yr Pg C yr Pg C yr -1 (9.9 Pg C in 2013) Le Quéré et al. (2013)

3 Global carbon budget ( ) 0.8 Pg C yr -1 Atmosphere 46% Pg C yr Pg C yr -1 (9.9 Pg C in 2013) Vegetation 28% Oceans 26% 26 millions tonnes CO2 per day Le Quéré et al. (2013)

4 Ocean: actor and victim of climate change Magnan et al. (2015)

5 Ocean: actor and victim of climate change Magnan et al. (2015)

6 Ocean: actor and victim of climate change Magnan et al. (2015)

7 Ocean acidification

8 What is ocean acidification? CO 2 is an acidic gas (it produces an acid when combined with water) Each of us adds 4 kg eq CO2 per day to the ocean (increasing acidity, reducing ph) Sam Dupont

9 ph ph and acidity

10 ph and acidity ph Acidity : x 10-9 mol H + kg % +34 %

11 Ocean acidification can be measured 60 N A 80 N Irminger Sea Iceland Sea B 40 S 45 S 50 S 165 E 175 E MUNIDA 20 N 40 N BATS ESTOC HOT CARIACO 150 W 120 W 90 W 60 W 30 W 0 Figure 1. Location map of the seven ocean carbon time-series sites, including Iceland Sea, Bates et al. (2014)

12 Ocean acidification can be measured 60 N A 80 N Irminger Sea Iceland Sea B 40 S 45 S 50 S 165 E 175 E MUNIDA 20 N 40 N BATS ESTOC HOT CARIACO 150 W 120 W 90 W 60 W 30 W 0 Figure 1. Location map of the seven ocean carbon time-series sites, including Iceland Sea, Bates et al. (2014) Range : to units yr -1 IPCC AR5 WG I

13 Time-series NW Mediterranean

14 Publication rate Papers: 561 in % in past 3 years +39% y-1 since 2000 vs +5% y -1 in WoS Authors: 1804 in 2013 Gattuso & Hansson, OA-ICC

15 Meta-analysis: Kroeker et al. (2013) Significant negative effect on: survival calcification growth development abundance Positive effect For Revi Negative effect Kroeker et al. (2013)

16 Changes to organisms and ecosystems Gattuso et al. (2014)

17 Changes to organisms and ecosystems Biological and ecological effects: high to low confidence Biogeochemistry: medium to low confidence Gattuso et al. (2014)

18 Changes to organisms and ecosystems Biological and ecological effects: high to low confidence Biogeochemistry: medium to low confidence Gattuso et al. (2014) Knowledge gaps: Multiple drivers Evolutionary adaptation Response of communities Food web, up to predators

19 Experimental space Riebesell & Gattuso (2015)

20 Benthic mesocosms: efoce experiment

21 Experimental setup Reference plot 1 m Control enclosure 2 m Experimental enclosure 2 m 1 m 1 m 1 m 2 m 1 m David Luquet

22 Photosynthesis Stimulated in individual leaves No change in the field David Luquet S. Schenone

23 No change in the abundance of organisms David Luquet

24 David Luquet We conclude that there is no effect on the seagrass, Posidonia oceanica Future meadows are at risk from ocean warming

25 Pelagic mesocosms David Luquet Slide: courtesy of F. Gazeau

26 Gazeau et al. (in prep.) Experimental conditions Summer 2012 Winter 2013 Slide: courtesy of F. Gazeau

27 Key results Very few effects of ocean acidification on these communities which are strongly nutrient-limited Nitrogen fixation stimulated in summer above 1000 µatm pco2 N fixation (nmol L -1 d -1 ) N fixation (nmol L -1 d -1 ) ph pco 2 (µatm) Rees et al. (sbm) Slide: courtesy of F. Gazeau

28 Future changes in ph

29 Future changes in ph

30 Biodiversity, CO2 vent, Ischia total loss of some calcareous species reduced biodiversity altered competitive dynamics between species regime shifts : totally different ecosystems warming may intensify the effects acidification Hall-Spencer and colleagues, Plymouth Univ.

31 CO2 vent, Spain Linares et al. (2015)

32 Ocean warming

33 Past warming Marbá et al. (2015) Marbá et al. (2015) Satellite data ( ): Summer SST: C C decade 1 in the western basin C decade 1 in the eastern basin

34 Temperature, Bay of Villefranche a Annual mean (0 to 75 m) a Summer anomaly (surface) Parravicini et al. (2015)

35 Adloff et al. (2015) Future warming Adloff et al. (2015) Composite of SST anomalies vs (largest and smallest anomaly out of the 6 scenario simulations at each grid point)

36 Warming: mass mortalities Gattuso et al. (2014). R. Berkelmans Also in the Mediterranean Sea

37 Warming: redistribution of species Poloczanska et al. (2014)

38 Commercial species > 75 % of bivalve production in the Mediterranean (Lacoue-Labarthe et al., in press) Gazeau et al. (2014) Slide: courtesy of F. Gazeau

39 Response of a Mediterranean mussel Excess mortality due to warming No effect of ocean acidification on growth Slide: courtesy of F. Gazeau Gazeau et al. (2014)

40 Survey of Mediterranean mussel producers Level of knowledge Rodrigues et al. (in press) Perception of level of threat Rodrigues et al. (in press)

41 Key ecosystems, species and impacts Ecosystem Key species Response to OA Response to warming Seagrass meadows Coralligenous reefs P. oceanica Increased productivity L. lichnoides, coral species Vermetid reefs V. triqueter, D. petraeum, N. brassicaflorida Crustose Coralline Algae (CCA) cease Slower calcification, recruitment Mussel beds M. galloprovincialis No response unless in high temp deterioration CCA and coral mortality Mortality Larval mortality Combined effect Greater mortality Greater mortality at low ph with increased temp

42 Global impacts of ocean acidification and warming REVIEW OCEANOGRAPHY Contrasting futures for ocean and society from different anthropogenic CO 2 emissions scenarios J.-P. Gattuso, 1,2,3 * A. Magnan, 3 R. Billé, 4 W. W. L. Cheung, 5 E. L. Howes, 6 F. Joos, 7 D. Allemand, 8,9 L. Bopp, 10 S. R. Cooley, 11 C. M. Eakin, 12 O. Hoegh-Guldberg, 13 R. P. Kelly, 14 H.-O. Pörtner, 6 A. D. Rogers, 15 J. M. Baxter, 16 D. Laffoley, 17 D. Osborn, 18 A. Rankovic, 3,19 J. Rochette, 3 U. R. Sumaila, 20 S. Treyer, 3 C. Turley 21 Science, July 2015

43 Future scenarios

44 Physics and chemistry Two scenarios considered Gattuso et al. (2015)

45 Physics and chemistry Two scenarios considered Significant gaps: Regional projections, e.g. sea level and low oxygen areas Projections in the coastal zone Changes in the internal and decadal variability Gattuso et al. (2015)

46 Projections for 2100 Thresholds: +1.5 C and -0.2 ph units relative to preindustrial RCP8.5: 69% of the ocean surface will exceed both thresholds RCP2.6: < 1% Gattuso et al. (2015)

47 Risks of impact on marine and coastal organisms and ecosystem services (A) (B) RCP RCP Present day Cumulative fossil fuel emissions since 1850 (GtC) 5* RCP8.5 RCP * 5* RCP Present 5* day * Krill Seagrass Mangroves Warm- Pteropods Bivalves (mid lat.) (high lat.) (mid lat.) (high lat.) water corals Coastal and marine organisms Changes in the global average of sea surface temperature sea surface ph RCP8.5 RCP4.5 RCP2.6 interva l RCP8.5 RCP4.5 RCP2.6 Global average sea surface temperature and ph at present and in 2100 according to the 3 RCPs. RCP8.5 RCP4.5 Gattuso et al. (2015) Open ocean carbon uptake Finfish RCP2.6 Present day ( ) 936 Coastal Recreational Bivalve Fin Fin fisheries protec- services fisheries & fisheries (mid & high tion from coral aquaculture (low lat.) lat.) reefs (mid lat.) Ecosystem services Risk of impact Undetectable High Moderate Very high Confidence levels for present-day and the 3 RCPs 1* very low low medium high 5* very high Figure 2 Atmospheric CO2 concentration (ppm) -0.4 RCP8.5 4 Change Changeininsea seasurface surfacetemperature temperature ( C ( Crelative relativeto to ) ) Change in sea surface ph (units relative to ) -0.5 (C)

48 Risks of impact on marine and coastal organisms and ecosystem services (A) (B) RCP RCP Present day Cumulative fossil fuel emissions since 1850 (GtC) 5* RCP8.5 RCP * 5* RCP Present 5* day * Krill Seagrass Mangroves Warm- Pteropods Bivalves (mid lat.) (high lat.) (mid lat.) (high lat.) water corals Coastal and marine organisms Changes in the global average of sea surface temperature sea surface ph RCP8.5 RCP4.5 RCP2.6 interva l RCP8.5 RCP4.5 RCP2.6 Global average sea surface temperature and ph at present and in 2100 according to the 3 RCPs. RCP8.5 RCP4.5 Gattuso et al. (2015) Open ocean carbon uptake Finfish RCP2.6 Present day ( ) 936 Coastal Recreational Bivalve Fin Fin fisheries protec- services fisheries & fisheries (mid & high tion from coral aquaculture (low lat.) lat.) reefs (mid lat.) Ecosystem services Risk of impact Undetectable High Moderate Very high Confidence levels for present-day and the 3 RCPs 1* very low low medium high 5* very high Figure 2 Atmospheric CO2 concentration (ppm) -0.4 RCP8.5 4 Change Changeininsea seasurface surfacetemperature temperature ( C ( Crelative relativeto to ) ) Change in sea surface ph (units relative to ) -0.5 (C)

49 ( C ( Crelative relativeto to ) ) 4 5* RCP8.5 RCP * 5* RCP * Present 5* Seagrass Mangroves Warm(mid lat.) water corals day Krill Pteropods Bivalves (high lat.) (mid lat.) (high lat.) Open ocean carbon uptake Finfish Coastal and marine organisms Coastal Recreational Bivalve Fin Fin fisheries protec- services fisheries & fisheries (mid & high tion from coral aquaculture (low lat.) lat.) reefs (mid lat.) Ecosystem services Risk of impact Undetectable High Moderate Very high Confidence levels for present-day and the 3 RCPs 1* very low low medium high 5* very high 936

50 Solutions Gattuso et al. (2015)

51 Gattuso et al. (2015) Summary

52 4 key messages 1. Ocean strongly influences the climate system and important provider of key services 2. Impacts already detectable, high risk of impacts well before 2100, even with a low emission scenario 3. Immediate and substantial reduction of CO2 emissions to prevent massive and mostly irreversible impacts 4. As CO2 increases, the protection, adaptation, and repair options become fewer and less effective

53 On the road to COP21 in Paris The Carbon Brief

54 On the road to COP21 in Paris Paris Agreement: Holding the increase in the global average temperature to well below 2 C above pre-industrial levels and to pursue efforts to limit the temperature increase to 1.5 C above pre-industrial levels The Carbon Brief

55 A timeline for net zero emissions Knutti et al. (2015)

56 Risks for ocean and society from different CO 2 emissions pathways Removed unpublished data

57