BSSC 2011 St. Petersburg, 26 August 2011

1. BSSC 2011 St. Petersburg, 26 August 2011 Regional Climate Change Assessments as a Service to Society: The BACC Example Marcus ReckermannHans-Jörg Isemer Hans von StorchAnders Omstedt and the BACC Author Team

2. Overview • Examples and principles for BACC-type assessments • BACC results (published 2008) • BACC 2

3. Why regional climate change assessments? Why care about regional climate change? • Global assessment done by IPCC (AR4 from 2007) • Climate changes NOT uniformly around the world • Impacts differ greatly around the world • Relevant political decisions are taken locally (adaptation) • Public and policy makers need scientifc information • Information scattered in numerous publications, largely difficult to access (language), let alone for non-scientists → Regional Climate Offices → Regional Climate Change Assessments

4. BACC (2005-2008) Climate Report for the Metropolitan Region of Hamburg (2007-2010) BACC II (2009-2013) NOSCCA North Sea Region Climate Change Assessment (2010-2014) 2 BACC-like assessments

5. Organisation BALTEX Science Steering Group and Scientific community The BACC process BACC Science Steering Committee Lead authors selects Draft chapter outlines and select Contributing authors 1st draft Management and Coordination ( BALTEX Secretariat ) Expert review 2nd draft Expert review Similar to IPCC process but no government reviewStrictly scientific Final draft Editing and Formatting Publication

6. Principles of BACC-like assessments Principles… • Writing team of experts from different expertises, lead authors responsible for grand topics (IPCC-style)Lead authors recruit contributing authors with special expertise • Exclusive use of „current legitimate knowledge“… What is that? • published and publicly available • peer reviewed articles from scientific journals • institutional reports • conference proceedings • No NGO or private company publications (e.g. Greenpeace, WWF, Shell, Munich-Re etc.) • No unpublished results • Objectivity: No mixing of personal views, agendas or missions to be mixed up with the scientific status; consensus view to be reached if possible • If consensus cannot be reached, this must be stated („we agree that we disagree“), and conflicting views should be described • Minority views should not be ignored if they are scientifically plausible

7. BACCground • Regional climate change assessments needed (IPCC has been doing global climate change assessments since 1990) • Vast amount of material available in the Baltic Sea basin (also partly inaccessible previousely). Purpose • to provide the scientific community (and the public) with an assessmentof ongoing and future climate change in the Baltic Sea Basin • is done by reviewing and assessing published scientific knowledge on climate change in the Basin BALTEX Assessment of Climate Change for the Baltic Sea basin - BACC BACC Book published in January 2008 • 84 authors from 13 countries contributed • > 2000 references, ~ 10 % non-English literature • Stakeholder involvement: Helsinki Commission (HELCOM) involved

8. BACC Chapter 1 Introduction and Summary Lead Authors: Hans von Storch, Anders Omstedt Chapter 2 Past and current climate change Lead Authors: Raino Heino, Heikki Tuomenvirta, Valery Vuglinskiy, Bo Gustafsson Chapter 3 Projections of future anthropogenic climate change Lead Author: L. Phil Graham Chapter 4 Climate-related change in terrestrial and freshwater ecosystems Lead Author: Benjamin Smith Chapter 5 Climate-related marine ecosystem change Lead Authors: Joachim W. Dippner, Ilppo Vuorinen Annexes Various authors provide up-to-date background “textbook” knowledge on all aspects of BACC

9. BACC Past and current climate change Air Temperature Changes in Baltic Sea basin near-surface air temperature for the period 1871-2004 relative to 1961-1990 • Significant positive trend with regional and seasonal variations • Warming trend in the north: + 1 ºC; in the south: + 0.7 ºC per 100 yrs (basin: + 0.85 ºC) • Warming trend is largest in spring • Regional change is slightly larger than on the global scale (IPCC-AR4: + 0.74 ºC per 100 yrs)

10. BACC Past and current climate change Precipitation • Large spatial and seasonal variations of precipitation, but trends towards… • More rain in winter (especially in the south) • More rain in spring (especially in the north) • Less rain in summer (especially in the south) • Overall slight increase Changes of precipitation over the Baltic Sea basin as ratios of the period 1976-2000 relative to 1951-1975Light green = Precipitation decreaseDark green = Precipitation increase

11. BACC Past and current climate change River ice Earlier ice break up in Tornionjoki river (Finland)

12. BACC Past and current climate change Wind and Storminess Number of low pressure systems (p<980 hPa) in Stockholm and Lund There is NO trend in windiness or storminess over the Baltic Sea Basin!

13. BACC Past and current climate change Sea ice Winter 2007/2008 mildest ever recorded

14. BACC Projections of future anthropogenic climate change Air Temperature Winter RCM: HIRHAM RCM projection for 2071-2100 relative to 1961-1990 (A2 scenario) RCM: RCAO GCM: HadAM3H GCM: ECHAM4/OPYC

15. BACC Projections of future anthropogenic climate change Air Temperature Air Temperature Animation RCM projection for 2071-2100 relative to 1961-1990 (A2 scenario)

16. BACC Projections of future anthropogenic climate change Precipitation Precipitation Animation RCM projection for 2071-2100 relative to 1961-1990 (A2 scenario)

17. BACC Projections of future anthropogenic climate change Total riverine discharge to the Baltic Sea RCAO projections for 2071-2100 relative to 1961-1990 Discharge peaks come earlier in the year Overall amounts increased Lower salinities expected

18. BACC Projections of future anthropogenic climate change Sea ice Mean number of ice days simulated by RCAO Present winter For the period 2071-2100 using the A2 emission scenario For the period 2071-2100 using the B2 emission scenario

19. BACC Terrestrial ecosystems The expected future warming is associated to a possibly accelerated continuation of the present trends in • Earlier spring phenological phases, • Northward species shifts • Increased growth and vigour of vegetation Terrestrial ecosystems in the south are projected to be a carbon source by the end of the century

20. BACC Impacts on marine ecosystems … increase of temperature… • Higher metabolic rates • Impact on acclimation capacity • Reduce the general fitness • Reduce enzyme activities • Shift in species composition (phytoplankton) • Enhanced cyanobacteria blooms … decrease of salinity… • Osmotic stress • Shift in species composition (phyto– & zooplankton) • Egg survival • Food quality for fish (growth rate) • Distribution of benthos • Reduction of fitness • Invading species … reduction in sea ice… • Ringed seal survival

21. BACC II: An update to BACC to be published in 2014 1st BACC II Lead Author Team Meeting in Gothenburg, Sweden23-24 November 2010 2nd BACC II Lead Author Team Meeting in Hamburg, Germany28-29 March 2011

22. BACC II: An update to BACC to be published in 2014 • Science Steering Group constituted mostly from BACC I Lead Authors • New lead authors and contributing authors (23 to date) • New in BACC II • Past climate variability: Holocene (10.000 yr) and historical time frame (1000 yr) • Sea level change • Socio-economic impacts: Agriculture and forestry, Urban complexes, Fisheries and aquaculture • Attributing causes of regional climate change: • Global warming, aerosols (natural and pollutants), land cover and resource management • „Summary brochure for policy makers and the public“

23. thebaccblog.blogspot.com Value for the managing of scientific knowledge Value for society of BACC-type assessment reports • Overview over the current conensus (and dissensus) view over the current state of research for • scientists • stakeholders • public Go to our websites www.baltex-research.eu/BACC2

24. Thank you!