Ocean acidification and climate change Dr Carol Turley OBE, Plymouth - - PowerPoint PPT Presentation

Ocean acidification and climate change

Dr Carol Turley OBE, Plymouth Marine Laboratory

Castle Debates, London, February 2018

The ocean absorbs over a quarter of man-made CO2 emissions

Land uptake Ocean uptake Fossil fuels

2002-2013 Carbon budget

Le Quéré et al 2013; CDIAC Data; Global Carbon Project 2013

91% 9%

45% CO2 stays in atmosphere

27%

27%

Deforestation

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 CO2 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

• spheric CO2

Se Seawater awater pC pCO2 Se Seawater awater pH pH

increase

At Atmo mosph spheric eric CO CO2 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'

Ocean acidification is not just pH change

increase

increase decrease increase

Affects carbonate saturation state – may cause CaCO3 to dissolve At Atmo mosph spheric eric CO CO2 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'

Ocean acidification is not just pH change

Ac Acid idificati ification

• n 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

• r the

he ch chemistr mistry y to

• reco

cover ver

Coccolithophores Fleshy algae Calcifying algae Echinoderms Corals

Cal alcificat cificatio ion n - 32% 32% Abu bundance ndance - 47% 47% Gr Growth wth

• 10%

10% Dev evel elopment

• pment -11%

11% Gr Growth wth + + 17 17% Gr Growth wth + + 17 17% Ph Phot

• tosynth
• synthes

esis is + 28 28%

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)

Cal alcificati cification

• n
• 40%

40% Survival rvival

• 34%

34% Gr Growth wth

• 17%

17% Dev evel elopment

• pment - 25%

25% Cal alcificat cificatio ion n

• 23%

23% Abu bundance ndance

• 80%

80% Ph Phot

• tosynth
• synthes

esis is - 28% 28%

Diatoms Molluscs

Hennige et al (2015). Proc Roy Soc B, 282

Cold water corals may be particularly vulnerable

They are important reef-like habitats around our shores

Cold-water coral (Lophelia) reefs Ross & Howell (2013)

A Olsen & J Tjiputra; OSPAR-ICES OA Study Group

present

RCP 2.6 2100 RCP 4.5 2100 RCP 6.0 2100 RCP 8.5 2100 Seafloor Ω aragonite (corrosive at Ω < 1.0)

habitat is made from live and 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. ~ 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

LIVE coral DEAD coral

Oc Ocean ean ac acidi idific fication ation an and cold d cold-wa water ter cor coral als s

Movie: Brad Seibel, University of Rhode Island

Pteropods shells are already dissolving in the Southern Ocean and off California

Bednaršek et al. 2012

Potential foodweb impacts from decrease in Pteropods

Pacific Salmon Pteropods

Aydin et al. (2005)

Key components of food for zooplankton and fish such as salmon and herring

Courtesy: R Feely

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

• f US$500k

Barros et al. (2013) Photo: Mike UIrban Elliott's Oyster House

Ec Economic

• nomic im

impacts pacts are sti are still ll ver very y un uncertain certain - but but alr already eady

• cc
• ccurring

urring in in so some regio me regions ns

Th The e oc

• cean

ean is is abs absorbing

• rbing ne

nearly arly al all the hea l the heat t en energy ergy fr from

• m gl

global

• bal wa

warm rming ing ca causing using it it to wa to warm: rm: 93% of heat Ocean warming

Ocean warming affects:

• Ocean deoxygenation
• Sea level rise
• Ocean circulation and mixing hence

weather and extreme events (eg strength of hurricanes)

Th The e oc

• cean

ean re receives ceives al all l th the e wa water ter fr from

• m mel

elting ting ic ice: e: …. along with thermal expansion, resulting in sea level rise

Image credit: UKOA, Sea Surface Consortium

100% of water Sea level rise

The ocean is at the frontline of climate change

… multiple stressors often occurring at the same time and place

Acid idifica ificatio tion Sea ea Leve vel Rise se Oxyge gen los

• ss

Warming ming Bad d manage nageme ment Poll lluta tants nts

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

Acid idifica ificatio tion Sea ea Leve vel Rise se Oxyge gen los

• ss

Warming ming Bad d manage nageme ment Poll lluta tants nts

Oce cean ans of St f Stre ress

=

+ + + + +

Di Dire rectly ctly re rele levant to CO vant to CO2 emi miss ssions ions and t d the he UN UNFC FCCC CC [A [Art rtic icle le 2, 2, UN UNFC FCCC] CC]

➢ Impacts will be strongest in coastal communities relying

• n marine productivity

and coastal protection ➢ Many of these are highly vulnerable and less able to adapt

Societal Impacts

• ~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

Conclusions on ocean acidification

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 CO2 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

• f im

impact pacts s to to oc

• cean

ean ec ecosyste

• systems

ms an and th d the goo e goods ds an and ser d services vices th they ey pr provide

• vide

We n We need eed mo more re am ambi bitious tious CO CO2 em emissions issions re redu duction ction

*Nationally Determined Contributions

Thank you

ct@pml.ac.uk

More information see: www.oceansofimpact.global