Ocean acidification and climate change Dr Carol Turley OBE, Plymouth Marine Laboratory Castle Debates, London, February 2018
T he ocean absorbs over a quarter of man-made CO 2 emissions 91% 27% Fossil fuels Land uptake 27% 9% 45% CO 2 stays in atmosphere Ocean uptake Deforestation 2002-2013 Carbon budget Le Quéré et al 2013; CDIAC Data; Global Carbon Project 2013
Th The o e oce cean an ha has s tak aken en up up 27 27% % of car f carbo bon n di dioxi xide de em emiss issio ions ns: : …. reducing atmospheric warming but causing ocean acidification 27% of CO 2 Ocean acidification
Oc Ocea ean n ac acidi idific ficat ation ion is is ha happe ppeni ning ng no now an w and is d is mea easurabl urable At Atmospheric ospheric CO 2 Se Seawater awater pC pCO 2 Se Seawater awater pH pH
At Atmo mosph spheric eric CO CO 2 and se d seawa water ter pH a pH are re li linked d by by th the 'c 'carbo rbona nate te ch chem emistry sys istry system' tem' increase Ocean acidification is not just pH change
At Atmo mosph spheric eric CO CO 2 and se d seawa water ter pH are pH a re li linked d by by th the 'c 'carbo rbona nate te ch chem emistry sys istry system' tem' increase increase increase Affects carbonate decrease saturation state – may cause CaCO 3 to dissolve Ocean acidification is not just pH change
Ac Acid idificati ification on is is 10 10 ti times es fa faster ter th than an at at an any y ti time e du duri ring ng at at le least ast th the e la last t 65 65 mil illion lion ye years ars If If it it co conti ntinues nues at the he sa same e rate (~RCP8. 8.5) 5) it it wi will ll take ke 10,000’s yrs yrs for or the he ch chemistr mistry y to o reco cover ver
Calcifying algae Fleshy algae Corals Abu bundance ndance - 47% 47% Ph Phot otosynth osynthes esis is - 28% 28% Gr Growth wth + + 17 17% Cal alcificat cificatio ion n - 32% 32% Abu bundance ndance - 80% 80% Diatoms Coccolithophores Molluscs Cal alcificati cification on - 40% 40% Survival rvival - 34% 34% Growth Gr wth - 17% 17% Ph Phot otosynth osynthes esis is + 28 28% Dev evel elopment opment - 25% 25% Cal alcificat cificatio ion n - 23% 23% Gr Growth wth + + 17 17% Echinoderms Combined results from these experiments show consistent responses (negative & positive) by different groups of organisms to decrease of 0.4 pH units Growth Gr wth - 10% 10% Dev evel elopment opment -11% 11% Metadata analysis by Kroeker et al (2013)
Cold water corals may be particularly vulnerable Hennige et al (2015). Proc Roy Soc B, 282
They are important reef-like habitats around our shores Cold-water coral ( Lophelia ) reefs Ross & Howell (2013) present RCP 2.6 2100 A Olsen & J Tjiputra; OSPAR-ICES OA Study Group RCP 4.5 2100 RCP 6.0 2100 RCP 8.5 2100 Seafloor Ω aragonite (corrosive at Ω < 1.0)
Ocean Oc ean ac acidi idific fication ation an and cold d cold-wa water ter cor coral als s LIVE coral can continue habitat is made from live LIVE to calcify and grow* and dead coral coral under projected future conditions DEAD *Shape and coral mineralisation changes. Unknown costs DEAD coral will start to dissolve and become weaker. ~ 70% of CWC habitats will be in corrosive water by 2100. Will CWC habitats degrade? Hennige et al. 2015, Büscher et al. 2017; Guinotte et al. 2006
Pteropods shells are already dissolving in the Southern Ocean and off California Movie: Brad Seibel, University of Rhode Island Bednaršek et al. 2012
Potential foodweb impacts from decrease in Pteropods Key components of food for Pacific Salmon zooplankton and fish such as salmon and herring Pteropods Courtesy: R Feely Aydin et al. (2005)
Economic Ec onomic im impacts pacts are sti are still ll ver very y un uncertain certain - but but alr already eady occ occurring urring in in so some regio me regions ns 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
Th The e oc ocean ean is is abs absorbing orbing ne nearly arly al all the hea l the heat t en energy ergy fr from om gl global obal wa warm rming ing ca causing using it it to wa to warm: rm: Ocean warming affects: 93% of heat • Ocean deoxygenation • Sea level rise • Ocean circulation and mixing hence Ocean warming weather and extreme events (eg strength of hurricanes)
Th The e oc ocean ean re receives ceives al all l th the e wa water ter fr from om mel elting ting ic ice: e: …. along with thermal expansion, resulting in sea level rise 100% of water Sea level rise Image credit: UKOA, Sea Surface Consortium
The ocean is at the frontline of climate change … multiple stressors often occurring at the same time and place + + + + + Warming ming Oxyge gen los oss Sea ea Leve vel Rise se Poll lluta tants nts Bad d manage nageme ment Acid idifica ificatio tion = Oce cean ans of St f Stre ress
The ocean is at the frontline of climate change … multiple stressors often occurring at the same time and place Dire Di rectly ctly re rele levant to CO vant to CO 2 emi miss ssions ions and t d the he UN UNFC FCCC CC [A [Art rtic icle le 2, 2, UN UNFC FCCC] CC] + + + + + Warming ming Oxyge gen los oss Sea ea Leve vel Rise se Poll lluta tants nts Bad d manage nageme ment Acid idifica ificatio tion = Oce cean ans of St f Stre ress
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
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
Wi Wide der con r concl clusion usions: s: Oc Ocean ean ch chemistr emistry y an and ph d physics ysics is is ch changing anging ra rapi pidly dly du due to CO e to CO 2 em emissions issions Cu Curr rrent ent *N *NDC DCs s ar are no e not eno t enough ugh to to avoi avoid d hi high ris gh risks ks of of im impact pacts s to to oc ocean ean ec ecosyste osystems ms an and th d the goo e goods ds an and ser d services vices th they ey pr provide ovide We n We need eed mo more re am ambi bitious tious CO CO 2 em emissions issions re redu duction ction *Nationally Determined Contributions
Thank you ct@pml.ac.uk More information see: www.oceansofimpact.global
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