7.5 COMFORT Synthesis paper

beyond tipping points- what did we learn from COMFORT

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Blenckner et al

Overall aim

• Natural & social dimension
• Broaden the scope = tipping points and change, plus rates
• => how can the knowledge of COMFORT be used => social, and relate to risk propeller => hazard, exposure, vulnerability
• Solution orientated

Structure of the manuscript

• 1. Introduction
• Ocean’s importance for climate, life and society
• integration of gradual change, extremes and tipping points across research communities and transformative ways for academia and community of practice
• 2. Risk of severe extremes, gradual and abrupt changes - quite crossings (resulting in a map with regional findings)
• 2.1 Climate-induced physical changes in the ocean (Gruber, Heinze, Frölicher, Henson, Hauck… ??)
• Quick overview of the major changes and rate-of change, ToE
• examples from the extremes and compounds events in different regions
• examples of different shifts in different regions
• 3. Consequences for ecosystems (Möllmann et al based on D4.4 Risk report
• Provinces and changes in novel and disappearing conditions
• Coral reefs
• Climate-fishing interactions
• 4. Transformative ways forward to avoid tipping points and severe impacts
• 4.1 Climate mitigation scenarios (Keller, Joos, Schwinger…
• carbon removal and mitigation scenarios
• overshoot – hysteresis => Jörg examples
• economics and carbon trade (Rickels)
• 4.2 Governance of research initiatives to form research and society platforms (Hov, Martins, Broadgate, Roden, Holland….)
• coordination of marine obs in 4 D –linked to model uncertainty areas or where we have missing data
• all in one place obs + model (biophysical+ biology) with clear organization + mandate – may be with warnings
•  address both change and tipping points (integrate the research community)
• Climate-species management targets
• Target –policy setting scenarios?
• platform for academia + community of practice
• future visions (Psychologists for future, Lea Dohm)
• 5. Outlook

2.1 Risks for severe climate-induced changes => major results from WP 1 and WP 2

Fig. 1: Global (ocean warming or abrupt change) map with links to boxes that show the major physical/biogeochemical regional changes and issues like compound extremes (findings from COMFORT)

Observed-based rate of change (1950-2014), IPCC et al 2021

Pacific Ocean

- Extreme compount events

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Arctic Ocean :

• 2 times higher warming rate
• 10 times higher acidification rate
• new mixes of Atlantic and Pacific waters
• Subsea permafrost melts leading to acidification and coastal erosion
• large decrease in summer ice cover, with projections of complete ice loss by 2050

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Atlantic Ocean

- Weakening of the Atlantic Meridional Overturning Circulation (AMOC)

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Southern Ocean

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3. Risks for ecosystems => major results from WP 3 and WP 4

Fig. 2: Risks propellers from different case studies => survey = D4.4

Simpson et al. 2021

Risks for Tipping Points for Corals in Seychelles : Risks and Solutions

T

Heatw

Juv coral density

Struc. Complex.

depth

MPAs

Fishing

Tourism?

Spatial and temporal heatwaves

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pH

Based on Graham et al 2015

4. Solution forwards – mitigation scenarios => COMFORT WP5 and WP6

Fig. 3: The results of ocean-based carbon-dioxide removal (CDR) approaches have a relatively small effect on atmospheric CO2 and temperature

Fig. 4a

• Risk of tipping points

Kloenne et al 2023

4. Recommendations towards solutions

4.1 Climate mitigation scenarios

• mitigation scenarios need to be more realistic, plus additional CDR are needed
• pronounced climate fluctuations in net zero emission scenarios that need to account for
• nationally Determined Contributions to GHG reductions need to be faster implemented and more ambitious to reduce the risks

4.2 Governance of research initiatives to interact with and serve society

• coordination of marine obs in 4 D –linked to model uncertainty areas or where we have missing data
• couple model development and application to a systematic development of the marine observation systems in 4-d , observation+model-based marine analysis, reanalysis and forecasting => platform
• all in one place obs + model (biophysical+ biology) with clear organization + mandate – may be with warnings
• address both change and tipping points (integrate the research community) and inform public
• target –policy setting scenarios?
• Future visions

• Fig. 4b Synthesis fig bringing the different aspects together

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• Ocean change both gradual and abrupt and tipping points (with hysteresis)
• Local/regional ecosystem consequences => risk propellers
• Mitigation – CDR
• Platform for ocean data (obs-model)
• Platform for Community of Research – Community of Practice
• Psychological aspects?
• Policy

Thank you

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 820989 (project COMFORT, Our common future ocean in the Earth system – quantifying coupled cycles of carbon, oxygen, and nutrients for determining and achieving safe operating spaces with respect to tipping points). The work reflects only the author’s/authors’ view; the European Commission and their executive agency are not responsible for any use that may be made of the information the work contains.

Coastal & enclosed basins

• Mediterranean Sea => warming, lower oxygen conc and strong acidification trend (stronger than Atlantic) in particular Eastern basin => affecting cold water corals
• Baltic Sea => becomes warmer and lower oxygen, novel food web conditions now and in the future expected, regime shifts found in the past due to climate-fishing , and recently Western Baltic cod => consequences for food web and society
• North Sea => at least 3 food web regime shifts found in the last 3 decades with the latest in the 2000s with clear hysteresis papers. Future projections indicate further shifts with very low bottom oxygen conditions with consequences for food webs

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Atlantic Ocean

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• Ocean uptake of anthropogenic CO₂ is leading to progressive acidification of surface and mid-depth waters in the Atlantic Ocean, the major CO₂ sink^7–12, subsequently threatening regional ecosystems. Projections suggest that exceeding CO₂ responsible for 2°C of warming would shift the environment to hazardous, non-optimal living conditions for cold-water corals and other marine organisms that require particular chemical conditions to build their calcium-based shells and other structures^11,12.
•  The subpolar North Atlantic Ocean currents are proposed as a global core tipping element of the climate system at a temperature increase of 1.1-3.8oC1. The current global warming lies at ~1.1°C and thus already within the lower bound of the critical range. Ocean currents weakening would have climatic impacts on decadal timescales, leading to regional cooling and weather extremes over Europe, as well as changes in global atmospheric circulation². These local ocean currents are connected to the Atlantic Meridional Overturning Circulation (AMOC) and their collapse may lead to an AMOC decline leading to severe changes in the Atlantic Ocean heat transport, Arctic sea ice extent and regional climate patterns

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• Potential interaction between different tipping elements in several regions of the Atlantic Ocean
• Subpolar ocean currents had destabilised previously in the 13^th and 14^th centuriesy leading to rapid ocean circulation changes and long-lasting regional climate change³. The destabilisation was associated with freshwater input from melting glaciers and the Arctic sea ice. This highlights the potential interaction between different tipping elements in different regions: the Greenland Ice Sheet, Arctic sea ice and the North Atlantic subpolar gyre.
• Cooling of the northern hemisphere as a result of a collapse strong decline of the Atlantic Meridional Overturning Circulation (AMOC) can be amplified by the Carbon dioxide removal (CDR) techniques

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• of the northern hemisphere as a result of a collapse strong decline of the Atlantic Meridional Overturning Circulation (AMOC) can be amplified by the Carbon dioxide removal (CDR) techniques

Arctic ocean

• The Arctic region is getting acidic (2x) and warmer (10x) faster than the rest of the globe with consequences for marine life
• The Arctic Ocean currents are changing due to increased freshwater inputsThe Arctic Ocean is being progressively “invaded” by the Atlantic and Pacific domains, leading to the mixing of two distinct ecosystems (Ingvaldsen et al. 2021). Additionally, the Arctic Ocean has been recently observed to already shift from light to nutrient limitation due to decreased sea ice cover and thus increased light availability. The consequences of these changes are detrimental and may trigger regional regime shifts in biological, physical-chemical properties (Polyakov et al. 2020, Drinkwater et al. 2021, Vernet et al. 2020, Kelly et al. 2020, Oziel et al. 2020).
• The Arctic region is prone to an increased intensity and frequency of extreme events
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Pacific Ocean

• Marine heat waves are increasing with severe impacts on fishes, very good example is the blob
• Acidification extremes => effects on plankton
• Deoxygenation events in the Eastern Pacific
• Warming projections increases the risk for exploited fish stocks , plus changes in the distribution, example the skipjack tuna, with severe consequences for low income island states

Southern Ocean

• Sea ice loss projections
• Acidification will affect food web
• Changes in phytoplankton communities due to changes in silicate are projected under high emission scenarios