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The selection of methods for projecting future impacts of climate change starts with a determination of whether causal relationships between variables internal to the study unit and the external drivers of change can be formally represented as a computational model. In adaptation situations where models are not available, vulnerability indication approaches can be used to say something about possible future impacts based on data collected on the current state of the study unit. Alternatively, knowledge elicitation provides a means of surveying and classifying expert and lay opinions about climate change and its potential impacts.

Modelling future impacts involves the deployment of methods and tools drawn from a formidable and ever-expanding range of options. br>
Table 3-6 is a matrix of impact studies, divided by sector of analysis and geographical location. Symbols after each study indicate the methods employed by the study: various types of modelling, integrated assessment, participatory scenario development, expert judgment and indicators. Some of the studies—particularly those with a global focus—use historical data as analogues, or base their methods around existing literature reviews. On the whole, studies presented in this table are impact assessments looking to the future that use climate projections and provide analysis on how those projections will impact on the various sectors in the various locations.


Table 3-6: Selection of impact studies, divided by sector and geographical focus, and
highlighting methods employed. Symbols are explained at the foot of the Table.

Location

Europe North
America
South
America
Africa
and
Middle
East
Asia Australasia Global
Sector
Agriculture Abildtrup
et al,
2006 * ^

Falloon
and
Betts,
2010 !
Zhang et
al, 2011b
!
Jones and
Thornton,
2003 %

Meza et al,
2008 % @

Ruane et al,
forthcoming
%
Abraha
and
Savage,
2006 %

Al Bakri
et al,
2011 %

Jones and
Thornton,
2003 %

Roudier
et al,
2011 !

Thornton
et al,
2010 %
Chavas et al,
2009 %

Lioubimtseva
and Henebry,
2009 @

Masutomi et
al, 2009 %

Srivastava et
al, 2010 %

Xiong et al,
2008 %

Wei et al,
2009 % &

Thomson et
al, 2006 %

Simelton et
al, 2009 + @
Luo et al,
2003 %

Pearson et
al, 2011 ! ~
Berg et al,
2012
(tropics)

Fraser, 2006
$ (famines)

Jacxsens et al,
2010 (food
safety supply
chain) !

Kang et al,
2009 % &

Mera et al,
2006 %
(soybean and
maize)

Nardone et al,
2010 @

(livestock)
Ramirez-
Vallegas et al,
forthcoming
% ~ (sorghum)

Sutherst et al,
2000 ! (pests)

Thornton et
al, 2009 @
(livestock
developing
countries)
Pollution Alcamo
et al,
2002 ^
McDonald
et al, 2005
@
Coasts and
Fisheries
(marine)
Philippart
et al,
2011 @
Badjeck et al,
2010 £

Brander,
2010 !
Ecosystems
and/or
biodiversity
De
Chazal et
al, 2008 !
*

Lindner
et al,
2010 ! ^

Van
Minnen
et al,
2002 ! +

Schröter
et al,
2005 !

Metzger
et al,
2008 ! +
Andalo et
al, 2005 !

Coops and
Waring,
2011 !

Coops et
al, 2012 !

Dale et al,
2010 ?

Dalla
Valle et
al, 2007 !

Ehman et
al, 2002 ?

Ivits et al,
2012 !

MacRae
et al, 2008
? !

Nitschke
and Innes,
2008 ?

Taner et
al, 2011 ?
Pettorrelli
et al,
2012
Tanaka et al,
2012 !
Chakraborty
et al, 2000
(plant
diseases) !

Sekercioglu
et al, 2012 !
@ (birds)

Sietz et al,
2011 ^
(drylands)

Stock et al,
2011 ! (living
marine
resources)
Urban Bonazza
et al,
2009 !
Hayhoe et
al, 2010 ^

Wuebbles
et al, 2010
^
Romero
Lankao et
al, 2012 ^
@ (more
adaptation,
less quant)
Gasper et al,
2011 @

Li et al, 2012
! (energy use
in buildings)
Romero
Lankao and
Qin, 2011 @

Willems et al,
2012 ! (urban
drainage)
Water Eckhardt
and
Ulbrich,
2003 &

Falloon
and
Betts,
2010 !
Boyer et
al, 2010 &

Chang
and Jung
2010 &

Kienzle et
al, 2012 &

Zhang et
al, 2011a &
De Silva et
al, 2007 &

Kelkar et al
2008 & #

Lioubimtseva
and Henebry,
2009 @

Park et al,
2010 @

Park et al,
2011 @

Varis et al,
2012 ! +
Green et al,
2011 @
(groundwater)
Transport Koetse and
Rietveld,
2009 @
Health Patz et al,
2008 !
Romero
Lankao et
al, 2012 ^
@ (more
adaptation,
less quant)
Lioubimtseva
and Henebry,
2009 @

Nelson, 2003
@


Vineis et al
2011 @
Energy Burkett,
2011! @
Mideksa and
Kallbekken,
2010 @
Coasts Nicholls,
2002 ! (sea
level
flooding)

Key for methods:
* = participatory scenario development
~ = expert judgment
^ = integrated model/integrated assessment
% = crop simulation model
£ = livelihoods framework
= vegetation models
? = forest ecosystem models
! = modelling
& = water models
$ = landscape ecology
@ = literature review / analysis / historical data
# = participatory knowledge elicitation
+ = indicators


A large proportion of climate change impact assessments make use of predictive models that describe the causal relationships between climate and a study unit. However, modelling tools tend to be available only for certain sectors such as agriculture, water resources, coastal zones, and terrestrial ecosystems. Technical requirements for projecting climate change impacts are generally high and often difficult to meet, so in many cases it will be preferable to adopt an existing model and tailor it for the adaptation context or to meet specific assessment needs. Models vary enormously in their complexity, in the spatial and temporal scale of their application, and in their assumptions about adaptation, but the process of impact projection (Box 3-5) is generally the same: select climate and socio-economic scenarios, select adaptation options and strategies, then compute impacts. Each of these steps is described in detail in the following sub-sections.

Box 3 5: Overview of Impact Projection

Theoretical assumptions
  • Interaction between the study unit and drivers of change can be 
    formally represented as a computational model
  • Adaptation can be formally represented as a computational model
Question addressed
  • What are the impacts of climate change?
Data requirements
  • Climate and socio-economic scenarios
  • Information about adaptation options
Typical result
A list of propositions that map each scenario and strategy for adaptation to
an impact.

Generic steps
1. Select climate and socio-economic scenarios
2. Select adaptation strategies
3. Compute the impacts of the scenarios and adaptations


Representing adaptation
Projecting impacts of climate change depends not only on the climate and socio-economic scenarios that are selected, but also on the assumptions that are made about adaptation. It is therefore important to carefully consider whether to choose models that project potential impacts, which are those that “may occur without considering adaptation” (Parry et al. 2007: 876), in contrast to tools that project residual impacts, which include adaptation.

Most natural and human systems will undergo some form of autonomous adjustment in response to either gradual changes in climate or sudden shocks, so it is generally understood that potential impacts will almost certainly not occur. However, it is important to note that the purpose of representing adaptation in impact projection is not to compute an optimal adaptation policy, but to model how different assumptions about the kinds of adjustments that are possible translate into differences in impacts. In other words, the selection of adaptation strategies to represent in impact projection serves the same purpose as the selection of climate and socio-economic scenarios, i.e. to explore a range of possible futures.

Pathfinder

Related decision tree of the Pathfinder:

Decision tree: Impact analysis