Climate change on the Mediterranean Sea:

Transcription

1 The European Commission s science and knowledge service Joint Research Centre Climate change on the Mediterranean Sea: from physical changes to ecosystems consequences Diego Macias European Commission Joint Research Centre, Directorate for Sustainable Resources, Via E. Fermi, 2749 (TP270), I Ispra (VA), Italy 1

2 1. General concepts; global change & oceans 2. Numerical models as tools for CC evaluation 3. Mediterranean Sea as CC hotspot Physical consequences Ecological impacts 2

3 1. Global change & oceans Our climate is changing (rapidly) Human actions in the background Anthropocene Large consensus and concern Basically altering the natural equilibrium of the climate components 3

4 1. Global change & oceans What s the role of the oceans? Oceans are key players of the climate system: Deep Chlorophyll Maximum Biological Carbon Pump 4

5 1. Global change & oceans What s the role of the oceans? Oceans are key players of the climate system: Oceans are victims of the climate change: Multifaceted, complex interactions, non-linear dynamics Chemical impacts Ocean Acidification Decrease ph Physical impacts Cisco Werner (2007) 5 Ecological impacts

6 1. General concepts; global change & oceans 2. Numerical models as tools for CC evaluation 3. Mediterranean Sea as CC hotspot Physical consequences Ecological impacts 6

7 2. Numerical models What s a model? Conceptualization of a real system a model is a logical machine for deducting the latter from the former (Gunawardena, 2013) All models are wrong, but some might be useful (G. Box) Ecosystem Model Models are rough approximation to very complex systems.. they are not the reality Hugo Macias 2010 (3yr old) 7

8 2. Numerical models What s a model? Ecosystem Model Hugo Macias 2010 (3yr old) BUT.. When carefully validated/verified models can be useful They allow to perform experiments: -> better understanding of complex dynamic processes (atmosphere-ocean) -> Testing of hypothesis/policy options (impacts of proposed measures) -> Testing the future, scenario generation to evaluate future impacts 8

9 1. General concepts; global change & oceans 2. Numerical models as tools for CC evaluation 3. Mediterranean Sea as CC hotspot Physical consequences Ecological impacts 9

10 3. Mediterranean Sea Climate change hotspot! Located in temperate latitudes Semi-enclosed basin Large population on developed countries Influence by developing areas from northern Africa Miniature ocean! Upwellings Deep water formation Mesoscale dynamics. 10

11 3. Mediterranean Sea Physical effects of climate change: Adloff et al., 2015 Somot et al., 2006 Temperature increase +1 C/+3 C by the end of 21 st century! Lazzari et al., 2013 Dubouis et al., 2011 Macias et al.,

12 3. Mediterranean Sea Physical effects of climate change: Temperature increase Salinity changes Evaporation Overall salinity expected to increase Dubouis et al., 2011 Precipitation Dubouis et al.,

13 3. Mediterranean Sea Physical effects of climate change: Temperature increase Salinity changes Density anomalies Stratification Regional differences! Uncertain! 13

14 3. Mediterranean Sea Physical effects of climate change: Temperature increase Salinity changes Density anomalies Stratification Winter mixing (deep water formation) Somot et al., 2006 Lazzari et al., 2013 DW formation rate expected to decrease 14

15 3. Mediterranean Sea Physical effects of climate change: Temperature increase Salinity changes Density anomalies Stratification Winter mixing (deep water formation) Herrmann et al., 2014 Somot et al., 2006 ~2100 ~2030 Surface area where DC takes place (km 2 ) 1e+5 8e+4 6e+4 4e+4 2e Days DCZ area hindcast DCZ area mpi45 DCZ area mpi85 DCZ area ec45 DCZ area ec85 DCZ area ENSEMBLE Macias et al., submitted Different time-horizons are considered 15

16 3. Mediterranean Sea Physical effects of climate change: Temperature increase Salinity changes Density anomalies Stratification Winter mixing (deep water formation) Ocean currents Adloff et al., 2015 Change of distribution paths (litter) Biogeochemical consequences Macias et al.,

17 3. Mediterranean Sea Physical effects of climate change: Temperature increase Salinity changes Density anomalies Stratification Winter mixing (deep water formation) Ocean currents Time-evolving nature of the change 17

18 3. Mediterranean Sea Scientist Stakeholder Time-evolving nature of the change Adloff et al., 2015 Somot et al., 2006 Macias et al., Macias et al., o C T with respect to 2012 ( o C) Atlantic Multidecal Oscillation unfiltered >14000 years Atlantic Multidecal Oscillation filtered Year Year 18

19 3. Mediterranean Sea Ecological Physical effects impacts of climate of climate change: 19

20 3. Mediterranean Sea Ecological impacts of climate change: 20

21 3. Mediterranean Sea Ecological impacts of climate change: Increasing complexity! 21

22 3. Mediterranean Sea Ecological impacts of climate change: The Mediterranean Sea is typically seen as an oligotrophic basin with few productivity hotspots 22

23 3. Mediterranean Sea Ecological impacts of climate change: The Mediterranean Sea is typically seen as an oligotrophic basin with few productivity hotspots Biological production (integrated) not changing that much 23

24 3. Mediterranean Sea Ecological impacts of climate change: The Mediterranean Sea is typically seen as an oligotrophic basin with few productivity hotspots Biological production (integrated) not changing that much Vertical stratification and mixing depth is expected to change in the future Lazzari et al.,

25 Surface Chla in blooming area (mg/m 3 ) 3. Mediterranean Sea Ecological impacts of climate change: The Mediterranean Sea is typically seen as an oligotrophic basin with few productivity hotspots Biological production (integrated) not changing that much Vertical stratification and mixing depth is expected to change in the future Somot et al., 2006 Macias et al., 2016 Time-evolving nature of the change Surface area where DC takes place (km 2 ) Spring bloom Maximum intensity of the chla bloom (mg/m 3 ) Present day Model DCZ area Model MODIS SEAWIFS (r 2 =0.5; p<0.01) (r 2 =0.46; p<0.01) Annual accumulated extension of DCZ (km 2 ) MODIS Model SEAWIFS (r 2 =0.75; p<0.01) 0 1e+6 2e+6 3e+6 4e+6 5e+6 6e Surface Chla (mg/m 3 ) Surface area where DC takes place (km 2 ) 1e+5 8e+4 6e+4 4e+4 2e+4 Spring bloom H2030 DCZ area hindcast DCZ area mpi45 DCZ area mpi85 DCZ area ec45 DCZ area ec85 DCZ area ENSEMBLE Chla hindcast Chla MPI45 Chla MPI85 Chla EC45 Chla EC45 Chla ENSEMBLE Maximum intensity of the chla bloom (mg/m 3 ) MPI45 MPI45 EC45 EC Annual accumulated extension of DCZ (km 2 ) e+6 4.0e+6 6.0e+6 8.0e+6 1.0e+7 1.2e+7 Days Days

26 Surface Chla in blooming area (mg/m 3 ) 3. Mediterranean Sea Ecological impacts of climate change: The Mediterranean Sea is typically seen as an oligotrophic basin with few productivity hotspots Biological production (integrated) not changing that much Vertical stratification and mixing depth is expected to change in the future Somot et al., 2006 Macias et al., 2016 Time-evolving nature of the change Surface area where DC takes place (km 2 ) Spring bloom Maximum intensity of the chla bloom (mg/m 3 ) Present day Model DCZ area Model MODIS SEAWIFS (r 2 =0.5; p<0.01) (r 2 =0.46; p<0.01) Annual accumulated extension of DCZ (km 2 ) MODIS Model SEAWIFS (r 2 =0.75; p<0.01) 0 1e+6 2e+6 3e+6 4e+6 5e+6 6e Surface Chla (mg/m 3 ) Surface area where DC takes place (km 2 ) 1e+5 8e+4 6e+4 4e+4 2e+4 Spring bloom H2030 DCZ area hindcast DCZ area mpi45 DCZ area mpi85 DCZ area ec45 DCZ area ec85 DCZ area ENSEMBLE Chla hindcast Chla MPI45 Chla MPI85 Chla EC45 Chla EC45 Chla ENSEMBLE Maximum intensity of the chla bloom (mg/m 3 ) MPI45 MPI45 EC45 EC Annual accumulated extension of DCZ (km 2 ) e+6 4.0e+6 6.0e+6 8.0e+6 1.0e+7 1.2e+7 Days Days

27 3. Mediterranean Sea Ecological impacts of climate change: The Mediterranean Sea is typically seen as an oligotrophic basin with few productivity hotspots Biological production (integrated) not changing that much Vertical stratification and mixing depth is expected to change in the future Now: summer months show accumulation of large-scale predators (tuna, cetaceans, etc..) Lambert et al., 2017 Stripped dolphins Laran et al., 2017 Summer: oligotrophy all over the Med Macias et al., 2015 Summer: intense North Current (fertilization) Future: increase suitability for large predators in summer months? 27

28 Concluding remarks Models can be useful tools to evaluate potential impacts: Global change Policy measures The Blue2 initiative: Network of Experts for ReDeveloping Models of the European Marine Environment (MEME) 28

29 Concluding remarks Models can be useful tools to evaluate potential impacts: Global change Policy measures Limitations and potentialities of the models should be clearly communicated Global change will likely impact the physical and biological conditions of the Mediterranean Sea Regional differences Transient state (time-horizons) Adloff et al.,

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