Ocean acidification and climate change

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1 Ocean acidification and climate change Dr Carol Turley OBE, Plymouth Marine Laboratory Castle Debates, London, February 2018

2 The ocean absorbs over a quarter of man-made CO 2 emissions 91% 27% Fossil fuels Land uptake 9% 27% 45% CO 2 stays in atmosphere Deforestation Ocean uptake Carbon budget

3 The ocean has taken up 27% of carbon dioxide emissions:. reducing atmospheric warming but causing ocean acidification 27% of CO 2 Ocean acidification

4 Ocean acidification is happening now and is measurable Atmospheric CO 2 Seawater pco 2 Seawater ph

5 increase Atmospheric CO 2 and seawater ph are linked by the 'carbonate chemistry system' Ocean acidification is not just ph change

6 increase Atmospheric CO 2 and seawater ph are linked by the 'carbonate chemistry system' increase increase decrease Affects carbonate saturation state may cause CaCO 3 to dissolve Ocean acidification is not just ph change

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8 Acidification is 10 times faster than at any time during at least the last 65 million years If it continues at the same rate (~RCP8.5) it will take 10,000 s yrs for the chemistry to recover

9 Corals Calcifying algae Fleshy algae Abundance - 47% Calcification - 32% Molluscs Photosynthesis - 28% Abundance - 80% Coccolithophores Growth + 17% Diatoms Calcification - 40% Survival - 34% Growth - 17% Development - 25% Calcification - 23% Echinoderms Photosynthesis + 28% Growth + 17% Growth - 10% Development -11% Combined results from these experiments show consistent responses (negative & positive) by different groups of organisms to decrease of 0.4 ph units Metadata analysis by Kroeker et al (2013)

10 Cold water corals may be particularly vulnerable Hennige et al (2015). Proc Roy Soc B, 282

11 A Olsen & J Tjiputra; OSPAR-ICES OA Study Group They are important reef-like habitats around our shores Cold-water coral (Lophelia) reefs Ross & Howell (2013) present RCP RCP RCP RCP Seafloor Ω aragonite (corrosive at Ω < 1.0)

12 Ocean acidification and cold-water corals habitat is made from live and dead coral LIVE coral DEAD coral LIVE coral can continue to calcify and grow* under projected future conditions *Shape and mineralisation changes. Unknown costs DEAD coral will start to dissolve and become weaker. Hennige et al. 2015, Büscher et al. 2017; Guinotte et al ~ 70% of CWC habitats will be in corrosive water by Will CWC habitats degrade?

13 Pteropods shells are already dissolving in the Southern Ocean and off California Movie: Brad Seibel, University of Rhode Island Bednaršek et al. 2012

14 Potential foodweb impacts from decrease in Pteropods Key components of food for zooplankton and fish such as salmon and herring Pacific Salmon Pteropods Aydin et al. (2005) Courtesy: R Feely

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17 Economic impacts are still very uncertain - but already occurring in some regions Pacific NW oyster hatcheries started declining in 2005, with 80% mortality by 2008 Declines caused by upwelled low ph waters, further impacted by ocean acidification Mitigation measures in place but these are a temporary solution Monitoring system installed but at a cost of US$500k Barros et al. (2013) Photo: Mike UIrban Elliott's Oyster House

18 The ocean is absorbing nearly all the heat energy from global warming causing it to warm: Ocean warming affects: Ocean deoxygenation 93% of heat Sea level rise Ocean circulation and mixing hence weather and extreme events (eg strength of hurricanes) Ocean warming

19 The ocean receives all the water from melting ice:. along with thermal expansion, resulting in sea level rise 100% of water Sea level rise Image credit: UKOA, Sea Surface Consortium

20 The ocean is at the frontline of climate change multiple stressors often occurring at the same time and place Acidification Warming Oxygen loss Sea Level Rise Pollutants Bad management = Oceans of Stress

21 The ocean is at the frontline of climate change multiple stressors often occurring at the same time and place Directly relevant to CO 2 emissions and the UNFCCC [Article 2, UNFCCC] Acidification Warming Oxygen loss Sea Level Rise Pollutants Bad management = Oceans of Stress

22 Societal Impacts Impacts will be strongest in coastal communities relying on marine productivity and coastal protection Many of these are highly vulnerable and less able to adapt

23 Conclusions on ocean acidification ~50% of all species tested were negatively affected by ocean acidification Effects of ocean acidification were amplified by other stressors Environmental changes are fast relative to evolutionary adaptation (higher organisms) Important ecosystem services are at risk

24 Wider conclusions: Ocean chemistry and physics is changing rapidly due to CO 2 emissions Current *NDCs are not enough to avoid high risks of impacts to ocean ecosystems and the goods and services they provide We need more ambitious CO 2 emissions reduction *Nationally Determined Contributions

25 Thank you More information see: