HELCOM Baltic Sea Action Plan in a warmer world

Transcription

1 HELCOM Baltic Sea Action Plan in a warmer world H.E. Markus Meier 1,2 1 Research Department, Swedish Meteorological and Hydrological Institute 2 Department of Meteorology, Stockholm University markus.meier@smhi.se

2 Content Results of the ECOSUPPORT project Discussion of limitations of the approach Recommendations for future research 2

3 Baltic Sea - how to approach the future? Combined effects of climate change and nutrient loads COD Ensemble modelling to quantify uncertainty SPRAT Decision support to policy makers

4 Baltic Sea - how to approach the future? Advanced modeling tool for scenarios of the Baltic Sea ECOsystem to SUPPORT decision making COD 11 partner institutes from 7 Baltic Sea countries

5 Baltic Sea: future projections 4 climate projections different global climate models A1B and A2 scenarios COD 2 realizations SPRAT 1(2) regional climate model (RCAO, CLM) 1(2) hydrological models 3 Baltic Sea models (BALTSEM, ERGOM, RCO-SCOBI) 3(4) nutrient load scenarios: BSAP, (CLEG), REF, BAU Total: 38(58) scenario simulations

6 Ensemble mean volume averaged temperature and salinity (Source: Meier et al., 2011a) 6

7 Ensemble average changes of the annual mean biologically available total nitrogen and phosphorus loads (Source: Meier et al., 2011a) 7

8 Ensemble average vertical profiles and changes between and in oxygen concentration at Gotland Deep observations BAU REF BSAP (Source: Meier et al., 2011a) 8

9 Volume averaged anoxic areas BAU REF BSAP observations (Source: Meier et al., 2011a) 9

10 Ensemble mean changes between and of a d annual mean phytoplankton concentration (in mg Chl m-3) and e h Secchi depth (in m) BSAP CLEG REF BAU (Source: Meier et al., 2012c) 10

11 BAU REF BSAP Primary production Nitrogen fixation Phosphorus release from the sediments Nitrogen release from the sediments Sediment phosphorus pool Ratio between release and phosphorus sediment pool Denitrification (Source: Meier et al., 2012c) Ratio between denitrification and nitrogen supply 11

12 Conclusions In future climate, increased loads and temperature dependent rates of biogeochemical processes may result in an overall intensification of internal nutrient cycling, including substantial increases in both primary production of organic matter and oxygen consumption for its mineralization.

13 Conclusions Without drastic nutrient load abatements hypoxic and anoxic areas are projected to increase. The BSAP does not result in an oligotrophic Baltic Sea ( prior to 1960s roughly). ECOSUPPORT was a big step beyond the state-of-the-art because we used 1. transient simulations ( ) 2. multi-model ensemble approach

14 AMBIO Special Issue, September

15 Conclusions Uncertainties of the projections are dominated by 1. unknown nutrient loads (bioavailability, nutrient retention in the coastal zone, scenarios), 2. biases of the GCMs/RCMs (hydrological cycle, estuarine circulation) and 3. biases of the biogeochemical models. For instance, we found largely differing sensitivities of the models to changing nutrient loads. In addition, the northern Baltic Sea biogeochemistry seems to be less well described.

16 Monthly mean 2m air temperature at Gotland Deep for (RCA with 50km) (Source: Meier et al. 2011b) 16

17 Water temperature 17

18 SST changes versus air temperature changes for winter and summer (Source: Meier et al., 2004c)

19 Seasonal SST changes ( C) RCAO/HadCM3 A1B (upper) and RCAO/ECHAM5 A1B (lower) minus DJF MAM JJA SON 19

20 Seasonal SST changes ( C) RCAO/HadCM3 A1B (upper) and RCAO/ECHAM5 A1B (lower) minus Northern Baltic amplification confirmed by satellite data DJF MAM JJA SON 20

21 Salinity 21

22 Ensemble mean volume averaged temperature and salinity (Source: Meier et al., 2011a) 22

23 Relative changes in precipitation (in percent) for the period , relative to Values are multi-model averages based on the SRES A1B scenario for December to February (left) and June to August (right). White areas are where less than 66% of the models agree in the sign of the change and stippled areas are where more than 90% of the models agree in the sign of the change. 23

24 Relative changes in precipitation (in percent) for the period , relative to Values are multi-model averages based on the SRES A1B scenario for December to February (left) and June to August (right). White areas are where less than 66% of the models agree in the sign of the change and stippled areas are where more than 90% of the models agree in the sign of the change. 24

25 25 Salinity at Gotland Deep Median profiles of salinity at monitoring station BY15 for present climate (black solid line, shaded areas indicate the +/- 2 standard deviation band calculated from two-daily values for ) and in projections for (colored lines). In (a) only effects from wind changes are considered whereas in (b) projections based upon wind and freshwater inflow changes are shown. Numbers in the legend correspond to the different scenario runs. (Source: Meier et al. 2006)

26 Runoff Kattegat Baltic proper Bothnian Sea Gulf of Riga Bothnian Bay Gulf of Finland Total Source: Meier et al. (2012b) 26

27 27 Sensitivity of salinity to the freshwater supply sensitivity experiments natural variability scenarios present climate (Source: Meier and Kauker, 2003b)

28 Recommendations for future research 1. New scenario simulations are needed based upon IPCC AR5 (sea ice, hydrological cycle, larger ensemble, saltwater inflows, sea level rise) 2. Climate - land use socioeconomy interaction/feedback 3. More plausible nutrient load scenarios consistent with large-scale developments 4. Multi-stressor approach (warming, de-oxygenation, eutrophication, overfishing, invasive species, pollutants) 5. Cost-effective implementation strategies of the BSAP will be developed based upon the information from spatially and temporally highly resolved modelling.

29 BALTEX and BSAP 7th Study Conference on BALTEX Borgholm, Island of Öland, Sweden, 10 to 14 June 2013 Changes in Energy, Water and Matter Cycles - 20 Years of BALTEX Research Building Regional Earth System Knowledge - A future programme for the Baltic Sea region Vision: Open international and interdisciplinary collaboration network providing service to society in the respect that thematic assessments (like BACC) provide an overview over knowledge gaps which need to be filled (e.g. by funded projects). 29

30 Thank you for your attention! Cyanobacteria bloom