Battarbe Does climate change pose a threat 2009 CHANGE RESEARCH CENTRE Birkbeck, March 13th, 2009 Rick Battarbee Environmental Change Research Centre UCL Does climate change pose a

ENVIRONMENTAL CHANGE RESEARCH CENTRE

Birkbeck, March 13th, 2009

Rick Battarbee

Environmental Change Research CentreUCL

Does climate change pose a threat to our freshwater ecosystems:


• Climate change revision• Evidence for unprecedented climate change• Evidence for change in remote freshwater lakes• The relative importance of climate change at the present time• Evidence from contemporary long term data-sets• Looking to the future – different approaches and examples• Implications of climate change for restoration policies and practice• Adaptive management• Conclusions

Outline


What are the current IPCC projections for climate change?


IPCC 2007

Current GCM projections for global mean temperature


IPCC 2007

Shift in global mean annual temperature patterns, comparing 2020s and 2090s and different scenarios


Shift in global precipitation patterns for the 2090s, comparing winter and summer

White areas show poor model agreement, stippled areas show strong model agreement

Wetter in high latitudes (especially in winter)Drier in low latitudes (especially in summer)


Is unprecedented climate change already occurring?


From Phil Jones

Global air temperature increase seems unprecedentedfrom the instrumental record!


From Wikipedia

On a 1000 year time-scale the picture is not so clear


But models only match measurements over the last 100 years ifgreenhouse gases are included


250

275

300

325

350

375

1000 1200 1400 1600 1800 2000

Mauna Loa atmosphericLaw Dome (Etheridge et al., 1996)Siple (Friedli et al., 1986)EPICA DML (Siegenthaler et al., 2005)S. Pole (Siegenthaler et al., 2005)

Age (Year AD)

CO

2 / pp

mv

And carbon dioxide concentrations are certainly unprecedented

380

275


But, what evidence is there that this has caused unprecedented changes in our freshwater ecosystems

so far?

Difficult to identify because:

(i) observational records are short and cannot be used to distinguish between greenhouse gas impacts and

natural variability

(ii) almost all surface waters in populated regions suffer from human impacts that mask the climate signals


River Thur, Switzerland(From Peter, EAWAG News 2006)

Hydromorphological modification

Ladybower, Stephen Walker


Soil erosion andland-use change

ENVIRONMENTAL CHANGE RESEARCH CENTRE acidification


Eutrophication


Water abstraction andsalinisation


Because of these masking stresses we need to go toremote regions where human impact can be assumed

to be minimal

Research in the last 15 years has focussed on lakesediment records from arctic and alpine regions


Elison Lake,Herschel Is.

(Douglas & Smol, Science, 1994,

Diatom evidence for unprecedented (?) change in high arctic lakes


(Catalan et al.JOPL, 2002)

Diatom evidence for unprecedented (?) change in alpine lakes


So we can argue that there have already been changes in climate due to increases in greenhouse gases and that there is evidence that this is reflected by changes in the ecology of

remote lakes over and above that expected as a result of natural variability.

Can we therefore find evidence for the impact of climate change on freshwater ecosystems in populated regions, despite the

dominance of other stresses?


Euro-limpacs

Integrated Project to Evaluate the Impacts of Global Change on European Freshwater Ecosystems

http://www.eurolimpacs.ucl.ac.uk

Euro-limpacs is a large (36 partners, 18 countries) EU projectco-ordinated by ECRC-UCL

2004-2009

See the Euro-limpacs Position Paper (Deliverable 301)

ENVIRONMENTAL CHANGE RESEARCH CENTRELong-term changes in river and stream temperatures in Switzerland

4

5

6

7

8

9

10

11

12

13

BA, 541 RH, 645 LU, 455 BR, 654 ME, 738 BG, 437 RE, 628 CH, 1701 HA, 1011 BE, 803 TN, 571 BI, 762 TR, 778 BY, 717 WE, 608 KE, 1050 TI, 1649 EM, 1069 AR, 1834 VB, 1732 MO, 1730 PO, 2099 SI, 2295 UR, 2012 BW, 2140

1990 200019801970

T [°C]River &altitude[m a.s.l.]

Increasing river temperature in Switzerland

(from Hari et al. (2006): Global Change Biol. 12: 10-26).


New EA database on river temperatures of over 30,000sites in England and Wales

From des Clers, Hughes & Simpson, UCL


River temperature change in the UK from 1990-2006

(degrees C/decade) Most sites show increases of between 0.3 and 0.6 degrees

per decade

River Dee @ LlandderfelSH982366 (146 m a.s.l.)

1974-2007 712 recordsLinear trend

+0.52 °C/decade (1985-2006)

From des Clers, Hughes & Simpson, UCL


A. mixta A. imperator

O. cancellatum*

S. sanguineum

S. sanguineum

Is this responsible for some southern species of dragon-fly showing northern range expansion?

(1995-2006)

From Steve Brooks, NHM


The long-term change in the summer biomass of phytoplankton in the Queen Elizabeth Reservoir in the UK.

Years

Chl

orop

hyll

(ug

L-1)

0

20

40

60

80

100

120

140

1980 1985 1990 1995 2000

From George et al (2005)

The key climatic driver has been an increase in the stability of the reservoir and the increased frequency of calm, sunny days

Is climate change leading to increased algal growth in lakes?


Is climate change responsible for increased algal growth and

invasive roach populations in Windermere?

Average [PO4-P] in first 4-weeks of year

0

5

10

15

20

25

30

1945 1955 1965 1975 1985 1995 2005Year

[PO

4-P]

/ mg

m-3

Windermere North BasinWindermere South Basin

y = 0.09x - 167.10R2 = 0.32

y = 0.16x - 315.84R2 = 0.18

y = 0.10x - 197.59R2 = 0.62

y = 0.20x - 389.20R2 = 0.47

0

2

4

6

8

10

12

1960 1970 1980 1990 2000 2010Year

Annu

al m

ean

Chl

a (m

g m

-3)

South Basin

North Basin

From Stephen Maberly, CEH


Long-term changes in Windermere: improvement following P-stripping but subsequent deterioration

Max Chla [JJA] (mg m-3)

0

5

10

15

20

25

30

1950 1960 1970 1980 1990 2000 2010Year

North Basin

South Basin

Mean zooplankton [JJA] (No. dm-3)

0

5

10

15

20

25

30

1950 1960 1970 1980 1990 2000 2010Year

North Basin

South Basin

Summer phytoplankton have increased in the last decade despite an initial marked reduction following tertiary P-removal in 1992

The increased phytoplankton has coincided with a marked decrease in the apparent grazing pressure from summer zooplankton



Hypothesis: roachinvasion followingclimate warming

Maitland 1972

Davies et al. 2004Pre 1990 1995

20000

10

20

30

40

1995 2000 2005

Cat

ch p

er u

nit e

ffort

(roac

h 10

0 m

-2 n

et d

-1)

NorthBasinSouthBasin



So water temperatures are increasing, probably as a result of global warming rather than natural variability and there is evidence that climate change is beginning to influence species distributions and the structure and functioning of

freshwater ecosystems in the UK, in expected and unexpectedways

What about the future?

How can projections be made?


• palaeolimnology– learning from the past beyond the range of the observational record

• space for time substitution– to explore the structure and function of ecosystems in potentially analogous

climatic conditions

• experiments (field manipulations, mesocosms)– to examine responses to projected climate under controlled conditions

• modelling (statistical and process based)– to understand processes and assess time-scale of response for differentscenarios based on climate projections

First, we need to establish, if possible, robust relationships between changes in climate variables and hydro-ecological responses

From the Euro-limpacs project


IPCC 2007

And then apply a climate change scenario for the future


Temperature

Spec

ies

abun

danc

e species 1species 2

Climate scenario: T

current future

Grenouillet et al. Euro-limpacs, Blanes 2008

Assessing the effect of temperature increase – fish in France


Cha

nge

in p

roba

bilit

yof

occ

urre

nce

Bam Am

mG

og

Chn

Rha

Gaa

Cog

Les

Lec

Ana Bar

Cht

Alb

Leg

Sas Lel

Rur

Sce

Cyc

Tht

Blb Tit

Sal Cac

Ala

Esl

Bab

Lol

Abb

Gyc

Pup

Php

Pef

Lap

Sat

-0.5

0

0.5

+

Comparison between the current and projected probabilities of occurrence under

HadCM3 A1Fi scenario using SpeciesDistribution Models (SDMs)

Contrasted responses to climate change between species

Species

Grenouillet et al. Euro-limpacs, Blanes 2008

Potential impact of temperature change on fish species occurrence in France


±0 0.5 1 1.5 20.25

Kilometers

Embankment

DitchHigh : 14

Low : 0

Assessing the effect of changing hydrology: the Elmley Marshes, North Kent

Ramsar site, SSSI, NNR

redshank

lapwingFrom Julian Thompson, UCL


From the TIMES newspaper 2005Concern following the previous dry winter

What about 2050?


Projections of water table depth based on hydrological modelling(MIKE SHE) forced by UKCIP02 climate scenarios for the 2050s

-0.1

0.1

0.3

0.5

0.7

0.9

1.1

1.325/06/97 25/10/97 25/02/98 25/06/98 25/10/98 25/02/99 25/06/99 25/10/99 25/02/00

Gro

undw

ater

dep

th (m

) CalibratedL-trwsML-trwsMH-trwsH-trws

b

Water table depth (PETtrws)

From Julian Thompson

From Mike Acreman

Salt marsh rush (Juncus gerardi),Sea arrow grass (Triglochin maritima),Divided sedge (Carex divisa)


Restoring shallow lakes from a turbid algal-dominated state to a clear-water plant-dominated state

Tai Hu, China

(Steffen et al. 2004) Photo Li Shijie 2005

Interactions between climate change and eutrophication –will CC make restoration of shallow lakes even more difficult?


Approaches – eutrophication experiments using mesocosms

• aquatic macrophyte response to nutrients and temperature in 24 temperature controlledtanks including sediments and mixed plankton (Erik Jeppesen, Denmark)

• phytoplankton response to nutrients and temperature in 48 temperature controlled tanks withand without fish (Brian Moss, UK)

submerged plant (Denmark) phytoplankton (UK)


Six lakes per country

From Moss et al. ECOFRAME

Eutrophication – space-time substitution and experiments

Space-time and mesocosm experiments with algae, zooplankton and fish across a N – S gradient


Eutrophication – resultsfor shallow lakes

• Higher fish fecundity• More intense fish predation• Shorter food chain• Increased algal biomass and

turbidity• Decreased oxygen

concentrations• Accelerated nutrient re-cycling

Solutions to eutrophication problemsare likely to require much morestringent nutrient control than in

cooler lakes

Fish:zooplankton

Zoopl:phytopl

Cold Cool WarmFrom Moss et al. 2003


Model calculated S deposition over Europe: 1980 – 2000 (mg S m-2)

1980 1995 2000

Interactions between climate change and acidification –will CC affect attempts to restore acidified lakes and streams?

From The UNECE website


Round Loch of Glenhead: diatom-inferred pHmeasured pH and MAGIC-modelled pH, 1800 - 2030

From Battarbee et al. 2005

Diatom evidence for acidification and slight recovery

2005 pH

20 ANC?

core traps

1800 1990 2004AD


seasalt deposition (storminess)

dust (desertification)

runoff (precipitation and more evapotranspiration)

weathering rate (temperature)

concentrations of organic acids (precip + temp)

pCO2 in soil air and water

forest growth (precip + temp + CO2)

organic matter decomposition (temp)

temperature

precipitation

wind

CO2

Modelling climate – acidification interactions

(from Wright et al. unpub.)

Possible climate effects on acidified lakes and streams


Climate – acidification interactions:evidence from palaeolimnology

in the Austrian Tyrol

Decadal-scale swings in pH (inferred from the diatom record)

follow similar swings in temperature from the instrumental record

(Psenner & Schmidt 1992)


Climate – acidification interactions: evidence from

palaeolimnology in the Scottish Cairngorms

Lochan Uaine


Climate – acidification interactions: increased discharge especially from winter storms may depress pH and offset

recovery in upland streams

4

4 .5

5

5 .5

6

6 .5

7

0 10 0 0 20 0 0 30 0 0 40 0 0D isc h ar g e (l/s )

pH

1 97 9 -1 9 841 98 5 -1 9 891 99 0 -1 9 941 99 5 -2 0 01

(from Hutchins et al. unpub.)

Afon Gwy, Wales


?

Can the reference state be used to define the target?

Implications for policy and management: the goal-posts are continually shifting

Battarbee et al. 2005


Trends of macroinvertebrate biodiversity in boreal lakes

Time

Res

pons

e

Acidified

Expected

Reference

Res

pons

e

Time

Observed

Acidified

Reference

habitat-dependent response

(from Stendera & Johnson unpub.)

Lake acidification in Sweden – how stable are thereference sites?

Positive trends in littoral and negative trends in sub-littoral and profundal habitats:related to temperature increase (increasing deep water anoxia?)


1800

1990

2004

or are there other explanations?- random?- hysteresis?- nitrate?

1800

Lake acidification in the UK: is climate change causing “recovery” towards a new reference?

Battarbee et al. unpub.


Eutrophication of Windermere: will climate change prevent restoration to “good” status?

y = 0.09x - 167.10R2 = 0.32

y = 0.16x - 315.84R2 = 0.18

y = 0.10x - 197.59R2 = 0.62

y = 0.20x - 389.20R2 = 0.47

0

2

4

6

8

10

12

1960 1970 1980 1990 2000 2010Year

Ann

ual m

ean

Chl

a (m

g m

-3)

South Basin

North Basin

From Stephen Maberly

?


To what extent can foreseen problems be avoided by adaptive management?

Do we have sufficient understanding to take effective action now?


Adaptive management: INCA-N scenarios to prevent nitrate increase in lowland rivers: what are the options?

0

2

4

6

8

10

12

1960 1980 2000 2020 2040 2060 2080 2100

mgN

/l

Baseline Fertiliser Deposition

Meadows Combined

Wade & Whitehead (unpublished)R. Lambourn


Adaptive management: excavating scrapes to preserve wetland habitat

±0 0.5 1 1.5 20.25

Kilometers

Embankment

Ditch

High : 14

Low : 0

Scrape

Scrapes 0.30 m deep, 0.55 km2

From Julian Thompson, UCL


Conclusions

• greenhouse gas-forced climate change is almost certainly taking place

• despite substantial natural variability there is growing evidence from lake sedimentrecords that unprecedented change is occurring in arctic and alpine lakes

• however, in populated regions, other stresses from human activity are still thedominant drivers of change

• evidence for the impact of global warming on UK surface waters can be inferred from increases in surface water temperatures, range expansion of dragon-flies,and increased algal growth in reservoirs and lakes

• examples of research that aims to predict the response of freshwater ecosystemsto future warming include range change in stenothermic taxa, hydrological stressin wetlands, intensification of eutrophication symptoms in shallow lakes, and increased acid episodes in upland streams


Conclusions (cont.)

• climate change undermines some of the basic concepts in current EU directives, especially the Water Framework Directive, with respect especially to the role ofthe reference state in defining targets

• in our research we need to continue attempting to understand the underlyingprocesses that control the response of freshwater ecosystems to climate change, but also need to evaluate alternative adaptive management strategies that might minimise damage in the future.

Documents

Battarbe Does climate change pose a threat 2009 CHANGE RESEARCH CENTRE Birkbeck, March 13th, 2009 Rick Battarbee Environmental Change Research Centre UCL Does climate change pose a