Module 2

Planning under uncertainty and

in the face of a changing

Global Climate Change AllianceSupport Facility

in the face of a changing

climate

Training workshops onmainstreaming climate change

Key topics covered by this module

• Basics of climate change science

• Sources of uncertainty

• Planning in the face of uncertainties and a changingclimateclimate

– Cost of inaction / Benefits of action

– ‘No-regrets’, ‘low-regrets’ and ‘robust’ measures

– Adaptive management

– Scenario planning

Basics of climate change scienceBasics of climate change science

Climate change is a reality

• IPCC 4th Assessment Report:– “Warming of the climate system is unequivocal, as is now

evident from observations of increases in global averageair and ocean temperatures, widespread melting of snowand ice and rising global average sea level”.and ice and rising global average sea level”.

• Observed trends:– Recent years warmest on record

– Accelerating increase in global surface temperature andocean temperature

– Accelerating rise in sea level

• This induces changes in physical and biologicalsystems

Some observations: trends inglobal mean temperature

Source: IPCC (2007b)4th Assessment Report,WG I – FAQ 3.1 Fig. 1

Observations and projections:global sea level change

Source: IPCC(2007b) 4th

AssessmentReport, WG I –FAQ 5.1 Fig. 1

Observations: intensity of cyclones

%age of Category 1 cyclone (blue curve), sum of Category 2 and 3 (green curve), sum ofcategory 4 and 5 (red curve) on 5 years period. Dashed lines are averages for each category

from 1970 to 2004 (Source: Petit & Prudent 2008, p. 42, from Webster et al. 2005)

Physical manifestations ofclimate change in the Pacific region

• Increased average air and oceantemperatures

• Rising sea levels

• More unpredictable rainfall patterns– e.g. increased intensity of precipitation– e.g. increased intensity of precipitation

– e.g. increased or decreased average annual precipitation(likely increase in the equatorial Pacific)

• More frequent and severe extreme weather events– Storms, droughts, floods

• Shifts in seasons– e.g. changes in monsoon season

Resulting changes in physicalsystems

• Alterations in hydrological patterns and flows

– e.g. changes in oceanic circulation patterns

– e.g. changes in water salinity, oxygen levels

• Changes in coastal processes• Changes in coastal processes

– e.g. changes in erosion patterns

Resulting changes in biologicalsystems

• Changes in terrestrial ecosystems

– e.g. shifts in the range of some species

– e.g. increased erosion and land degradation

• Changes in marine and freshwater ecosystems• Changes in marine and freshwater ecosystems

– e.g. shifts in the range and abundance of plankton andfish

• Many other changes have been documented butmay be attributable at least in part to other causes

– e.g. degradation and loss of coastal wetlands, mangroves,coral reefs

Causes of change

• Natural variation is an inherent feature of theclimate (e.g. driven by solar cycles, earth orbit, volcanoes)

• But anthropogenic emissions of long-livedgreenhouse gases in the atmosphere are a majorgreenhouse gases in the atmosphere are a majorcause of the changes now being observed

Evolution of GHG concentrations

Source: IPCC(2007b) 4th

AssessmentReport, WG I –FAQ 2.1 Fig. 1

The greenhouse effect

Source: WWF/IPCC

Main greenhouse gases

• By decreasing order of abundance:

– water vapour (H2O)

– carbon dioxide (CO2)

– methane (CH4)– methane (CH4)

– nitrous oxide (N2O)

– ozone (O3)

– chlorofluorocarbons (CFC)

– other halogenated compounds (i.e. gases containing fluorine,

chlorine, bromine or iodine) (e.g. hydrofluorocarbons – HFC,sulphur hexafluoride – SF6)

IPCC GHG emission scenarios

Source: IPCC 4thAssessment report –Synthesis report,Fig. 3.1

Projections over the 21st century –Southern Pacific

Change in t° (°C) Change in precipitation (%)

2010-2039 2040-2069 2070-2099 2010-2039 2040-2069 2070-2099

Comparison with the 1961-1990 periodProjections from 7 global models for the A1FI, A2, B1 & B2 scenarios

+0.45 to+0.82

+0.80 to+1.79

+0.99 to+3.11

-3.9 to +3.4 -8.2 to +6.7-14.0 to+14.6

Source: IPCC 4th Assessment Report – Working Group IIChapter 16, Table 16.1, p. 694

Projections for the end of the21st century – South Pacific islands

Δ t° (°C) Δ precipitation (%) Extreme seasons (%)

Season Min. Med. Max. Min. Med. Max. Warm Wet Dry

DJF +1.4 +1.8 +3.2 -6 +4 +15 100 19 4

2080-2099 period compared with the 1980-1999 periodProjections from a set of 21 global models for the A1B scenario

DJF +1.4 +1.8 +3.2 -6 +4 +15 100 19 4

MAM +1.4 +1.9 +3.2 -3 +6 +17 100 35 1

JJA +1.4 +1.8 +3.1 -2 +3 +12 100 27 3

SON +1.4 +1.8 +3.0 -8 +2 +5 100 - -

Annual +1.4 +1.8 +3.1 -4 +3 +11 100 40 3

Source: IPCC 4th Assessment Report – Working Group IChapter 11, Table 11.1, p. 857

Projections for the end of the21st century – Southeast Asia

Δ t° (°C) Δ precipitation (%) Extreme seasons (%)

Season Min. Med. Max. Min. Med. Max. Warm Wet Dry

DJF +1.6 +2.5 +3.6 -4 +6 +12 99 23 2

2080-2099 period compared with the 1980-1999 periodProjections from a set of 21 global models for the A1B scenario

DJF +1.6 +2.5 +3.6 -4 +6 +12 99 23 2

MAM +1.5 +2.7 +3.9 -4 +7 +17 100 27 1

JJA +1.5 +2.4 +3.8 -3 +7 +17 100 24 2

SON +1.6 +2.4 +3.6 -2 +6 +21 99 26 3

Annual +1.5 +2.5 +3.7 -2 +7 +15 100 44 3

Source: IPCC 4th Assessment Report – Working Group IChapter 11, Table 11.1, p. 855

Projections for the end of the21st century – Sea level rise

• Models predict that sea level rise in the SouthPacific (as well as Southeast Asia) will be similar tothe global average, i.e.

– from a range of 0.18 – 0.38 m (B1 scenario)– from a range of 0.18 – 0.38 m (B1 scenario)

– to a range of 0.26 – 0.59 m (A1FI scenario)

for the period 2090-2099 relative to 1980-1999

Sources of uncertaintySources of uncertainty

Socio-economic uncertainties

• Socio-economic uncertainties (e.g. related to futurepopulation growth, economic growth, technological

choices, societal choices, international relations):

– influence the level of future emissions and thus the– influence the level of future emissions and thus themagnitude of climate change

– also, create uncertainties about future vulnerability toclimate change

Scientific uncertainties

• For any given emission scenario, differentatmosphere-ocean general circulation models(AOGCMs) provide different projections of futurechange – sometimes very different oneschange – sometimes very different ones

• Due to the complexity of the climate system,many uncertainties prevail and will persist overthe evolution of climate

Uncertainties in climate changeprojections

• Temperatures and sea levels:

– consensus that they will increase

– magnitude of the increase quite uncertain

• Rainfall:

– expected to increase overall

– but some regions are likely to get more and some less

– for many regions in the world, uncertainty about thedirection of change

• Changes in extreme parameters:

– average future conditions are easier to project thanextremes

Problems associated withdownscaling

• In developing countries in particular, the dataneeded to downscale higher-level projections ofclimate change to the local or regional level areoften missingoften missing

• The level of uncertainty is greater at downscaledlevels than at large scales

• Downscaling is particularly complex for small islands

– Major role of ocean–atmosphere interactions

– Uncertainty increases w/ distance from large land masses

Specific uncertainties for thePacific region

• Regional distribution of sea level rise

– Will not be geographically uniform, due to uneven oceandensity (linked to temperature, salinity) and circulationchanges

• Regional distribution of changes in tropical cyclones

– Uncertainty on future El Niño Southern Oscillationbehaviour contributes to uncertainty with regard to tropicalcyclone behaviour

• Few models address storm surges

Planning in the face of uncertaintiesPlanning in the face of uncertainties

The cost of inaction

• The uncertainties surrounding climate changeare often invoked to justify inaction

• In a medium- to long-term perspective, however,inaction now is likely to be more costly:inaction now is likely to be more costly:

– Failure to adapt => wasted investment, increasedvulnerability

– Failure to reduce emissions => greater magnitude ofclimate change, more harmful impacts, higheradaptation costs in future

The benefits of action

• Some climate adaptation and mitigationmeasures are expected to provide developmentalbenefits, whatever the scope and magnitude ofclimate change and even in the absence of changeclimate change and even in the absence of change

• Even in the face of uncertainty, some types ofmeasures are justified.

Justified measures in the face ofuncertainty (1)

• ‘No-regrets’ measures:

– those that are expected to produce net benefits for societyeven in the absence of climate change (adaptation) orindependently of any ‘reward’ for mitigation (zero ornegative net cost at a zero carbon price)negative net cost at a zero carbon price)

• ‘Low-regrets’ measures:

– those that are expected to have a cost for society, but anacceptable one in view of the benefits they would bring ifclimate change turns out to produce significant effects(adaptation), or to have a low net cost at zero or lowcarbon prices (mitigation)

Justified measures in the face ofuncertainty (2)

• ‘Robust’ measures:

– those that produce net benefits or deliver good outcomesacross various possible climate change or carbon pricescenarios and economic development scenarios (ratherthan just under the ‘most likely’ scenario)than just under the ‘most likely’ scenario)

• Robust decision making ‘involves evaluating optionsto minimize expected regret across a variety ofmodels, assumptions, and loss functions’ (World Bank,

WDR 2010)

Adaptive management

• Adaptive management: a flexible and pragmatictype of management, aimed at continuallyimproving management policies and practices, onthe basis of ‘learning by doing’the basis of ‘learning by doing’

– Uses pilot projects and experiments; results andoutcomes are analysed and lessons learnt beforescaling up or adjusting responses

– Involves robustness as a decision criterion, the inclusionof safety margins in investment and the choice ofreversible/flexible options

• Well suited to situations involving uncertainties

Scenario planning (1)

• To support the choice of adaptation measures,scenarios reflecting prevailing uncertainties can bedeveloped, e.g.

– ‘no change’ (= baseline)

– ‘moderate change’

– ‘high change’

– higher temperatures combined with an increase as well asa decrease in rainfall

Scenario planning (2)

• Besides changes in climate conditions,scenarios typically describe some of the resultingbiophysical and/or socio-economic changes

– e.g. infrastructure and populations affected by a givenrise in sea level or increase in storm intensityrise in sea level or increase in storm intensity

• Scenario development should involve:

– key experts with a suitable range of technicalcompetences

– other national stakeholders (e.g. government, civilsociety organisations), for their knowledge of localconditions

Scenario planning (3)

• Once scenarios have been designed:

– Potentially suitable adaptation or mitigation options areidentified

– The costs and benefits of these options are calculated foreach of the chosen scenarios

• A comparison of costs and benefits across thevarious scenarios allows the identification of no-regrets, low-regrets and ‘robust’ measures

Use of scenarios: illustration (1)

Exhibit 1 – Scenarios for long-term sea level rise in Samoa; in the highchange case, sea level might rise by up to ~26cm by 2030

Today’s climatescenario

2030 estimated sea level rise against 2008 levelCentimeters

0.9

Sea level rise scenarios in Samoa by 2030 compared to 2008

00 2.02.0

Yearly sea level riseMillimeters

SOURCES: IPCC 4th AR; Rahmstorf (2009); CSIRO; team analysis

Moderate changescenario based onA2 scenariowithout ice flow

High changescenario based onA2 scenario withice flow

3.5

11.9

Sea levelrise inSamoa

26.2

Geologicalsubsidencein Samoa

2.0

Correctionfor localeffect inSamoa

0

Globalseal levelrise

24.2

7.68.12.0-2.5

Source: Economics of Climate Adaptation (2009) Test case on Samoa –Focus on risks caused by sea level rise, Fig. 01, p. 121

Use of scenarios: illustration (2)

Today’sclimatescenario

Horizontal retraction of freshwater lens due to sealevel rise, in meters

2 to 3

0 to 1

3 to 5

Savai’i

Upolu

Exhibit 2 – The freshwater lens is expected to retract by ~ 30 meters inUpolu and ~10 meters in Savai'i by 2030

ΔL

),m

120

140

160

180

Currentaverage

10% decrease(minimum annualrainfall projectedby global climate

model)

10% increase(maximum annualrainfall projectedby global climate

model)

However, salinization is highly sensitive to changes inaverage annual rainfall

SOURCE: Team analysis; CMIP3 global models

Moderatechangescenario

Highchangescenario

5 to 10

3 to 5

25 to 35

10 to 15

Both depth and location,particularly distance from coast)

will affect the salinization ofindividual wells

Annual rainfall, m

Sh

ift

of

len

s(Δ

0

20

40

60

80

100

2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4

A 10% decrease in rainfall coulddouble the expected horizontal

retraction of the freshwater lens inthe high change scenario

Source: Economics of Climate Adaptation (2009) Test case on Samoa –Focus on risks caused by sea level rise, Fig. 02, p. 122

Tools supporting scenariobuilding (1)

• Data and information provision tools thatgenerate or present data/information on:

– main climate variables (observations, projections)

– secondary climate impacts (e.g. on crop yields)– secondary climate impacts (e.g. on crop yields)

– examples of adaptation options

• Examples of such tools:

– World Bank Climate Change Data Portal(http://sdwebx.worldbank.org/climateportal)

– Climate Change Explorer (http://www.weadapt.org)

Source: OECD (2010a)

Tools supporting scenariobuilding (2)

• Existing reports, studies already conducted atregional, national or sub-national level

– studies conducted by national meteorological service

– e.g. NAPAs, national Communications to the UNFCCC– e.g. NAPAs, national Communications to the UNFCCC

– e.g. region-specific chapters of IPCC 4th Assessment

• Knowledge sharing tools:

– Adaptation Learning Mechanism(http://www.adaptationlearning.net/)

• Multi-disciplinary expert opinion combined with localknowledge

Tools supporting scenariobuilding (3)

• In the Pacific region: SOPAC’s Geonetworkwebsite (http://geonetwork.sopac.org/geonetwork/srv/en/main.home)

– interactive maps

– GIS datasets– GIS datasets

– satellite images and related applications

References (1)

• Economics of Climate Adaptation Working Group (2009) Shaping climate-resilient development: aframework for decision-making. Climate Works Foundation, Global Environment Facility,European Commission, McKinsey & Company, The Rockfeller Foundation, Standard CharteredBank & Swiss Re. Available from:http://www.mckinsey.com/clientservice/Social_Sector/our_practices/Economic_Development/Knowledge_Highlights/Economics_of_climate_adaptation.aspx

• IPCC (2007a) Climate Change 2007: Synthesis Report. Contribution of Working Groups I, II and II• IPCC (2007a) Climate Change 2007: Synthesis Report. Contribution of Working Groups I, II and IIto the Fourth Assessment Report. [Core Writing Team, Pachaury R.K. & Reisinger A. (eds.)]Intergovernmental Panel on Climate Change, Geneva. Available from: www.ipcc.ch

• IPCC (2007b) Climate Change 2007: The Physical Science Basis. Contribution of Working GroupI to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [SolomonS., Qin D., Manning M., Chen Z., Marquis M., Averyt K.B. , Tignor M. & Miller H.L. (eds.)].Cambridge University Press, Cambridge, UK & New York, NY, USA. Available from: www.ipcc.ch

• IPCC (2007c) Climate Change 2007: Impacts, Adaptation and Vulnerability. Contribution ofWorking Group II to the Fourth Assessment Report of the Intergovernmental Panel on ClimateChange [Parry M.L., Canziani O.F., Palutikof J.P., van der Linden P.J. & Hanson C.E. (eds.)].Cambridge University Press, Cambridge, UK & New York, NY, USA. Available from: www.ipcc.ch

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References (2)

• OECD (2010a) Climate Risk Screening and Assessment Tools: Making Sense of a CrowdedField. [Unpublished] Document distributed at the Meeting of the OECD DAC-EPOC Joint TaskTeam on Climate Change and Development Co-operation, 12-13 October 2010, Amsterdam.

• Petit J. & Prudent G. (eds) (2008, reprint 2010) Climate Change and Biodiversity in the EuropeanUnion Overseas Entities. IUCN, Gland, Switzerland and Brussels, Belgium. Available from:http://data.iucn.org/dbtw-wpd/edocs/2010-064.pdf

• UNDP-UNEP (2010) Mainstreaming Adaptation to Climate Change into Development Planning: AGuidance Note for Practitioners. Draft version. UNDP-UNEP Poverty-Environment Initiative. Finalversion available from: http://www.unpei.org/knowledge-resources/publications.html

• World Bank (2010a) Development and Climate Change. World Development Report 2010. WorldBank, Washington, DC. Available from: http://go.worldbank.org/ZXULQ9SCC0

• WWF – Climate change explained: http://wwf.panda.org/about_our_earth/aboutcc/how_cc_works/

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