From Alcamo, J.

29 Pages·2008·0.4 MB·English

From Alcamo, J. (Ed.) 2008. Environmental Futures: The Practice of
Environmental Scenario Analysis. Elsevier. In press.
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1 1
2 CHAPTER SIX 2
3 3
4 4
The SAS Approach: Combining Qualitative
5 5
6 and Quantitative Knowledge in 6
7 7
8 Environmental Scenarios 8
9 9
10 10
11 JosephAlcamo* 11
12 12
13 13
14 14
15 Contents 15
16 1. Introduction 123 16
17 2. FeaturesofQualitativeandQuantitativeScenarios 124 17
18 3. TheWorldWaterVisionScenarios–TheWorldWaterSituationin2025 127 18
19 4. TheSRESScenariosoftheIPCC–GlobalGreenhouseGasEmissionsupto2100 129 19
20 5. TheScenariosoftheMillenniumEcosystemAssessment–TheStateofWorld 20
Ecosystemsupto2050 131
21 21
6. TheGEO-4Scenarios–TheGlobalEnvironmentupto2050 135
22 22
7. TheSAS(StoryandSimulation)ApproachtoScenarioDevelopment 137
23 23
8. AdvantagesofSAS 140
24 24
9. DrawbacksofSASandaWayForward... 141
25 9.1 Thereproducibilityproblem 141 25
26 9.2 Theconversionproblem 143 26
27 10.Summingup 147 27
28 Acknowledgements 148 28
29 Uncitedreferences 148 29
30 References 148 30
31 31
32 32
33 33
34 34
Form follows function – Architect Louis Sullivan, 1896
35 35
36 36
37 37
38 1. Introduction 38
39 39
40 40
Although the maxim “form follows function” was coined with buildings in
41 41
mind,1 it can also be applied to scenarios which tend to take the qualitative form
42 42
43 * CenterforEnvironmentalSystemsResearch,UniversityofKassel,Germany 43
44 1 Sullivan,LouisH.,1896.Thetallofficebuildingartisticallyconsidered.Lippincott’sMagazine,March1896. 44
45 45
EnvironmentalFutures,3 ©2009ElsevierLtd.
46 1574-101X. Allrightsreserved. 46
123
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124 J.Alcamo
1 when used for education or planning, and quantitative when the aim is research. 1
2 But we will see in this chapter that many contemporary environmental studies re- 2
3 quire both qualitative and quantitative scenarios. Besides, recent experience shows 3
4 that the advantages of both types of scenarios can be captured by combining them 4
5 in a single scenario exercise. This chapter analyzes the pros and cons of qualitative 5
6 and quantitative scenarios and how they fulfill the different requirements of sce- 6
7 nario developers and users. It also describes major international scenario exercises 7
8 in which combined scenarios were used. This international experience is then dis- 8
9 tilled into a general procedure for combining qualitative and quantitative scenarios 9
10 called the SAS (“Story and Simulation”) approach. Finally the successes and draw- 10
11 backs of this approach are pointed out and some ideas are presented for producing 11
12 more scientifically-sound scenarios. 12
13 13
14 14
15 15
2. Features of Qualitative and Quantitative Scenarios
16 16
17 17
18 Although there is no standard way to distinguish between “qualitative” and 18
19 “quantitative” scenarios, qualitative scenarios are usually taken as those describ- 19
20 ing possible futures in the form of words or visual symbols rather than numerical 20
21 estimates.Theycantaketheshapeofdiagrams,phrases,oroutlines,butmorecom- 21
22 monly they are made up of narrative texts often called “storylines.” Qualitative 22
23 scenarioshavetheadvantageofbeingabletorepresenttheviewsofseveraldifferent 23
24 stakeholdersandexpertsatthesametime.Well-writtenstorylinescanbeanunder- 24
25 standable and interesting way of communicating information about the future, at 25
26 least as compared to dry tables of numbers or confusing graphs. 26
27 Qualitative scenarios have performed important functions in environmental 27
28 science and policy. They have been useful for gathering views from experts or 28
29 policy-makers on possible future societal developments and their environmental 29
30 implications,aswellastohelpstakeholders,policymakersandothersto“thinkbig” 30
31 aboutanenvironmentalissue,i.e.totakeintoaccountthelargetimeandspacescales 31
32 of a problem (see, e.g. Bood and Postma, 1997; Rothman et al., 2007). Qualitative 32
33 scenarios have also been used to raise the awareness of policymakers, stakehold- 33
34 ers, citizens and students about environmental problems and possible ways to solve 34
35 them.“Strategy-driven”scenariostendtobequalitative,asdescribedinChapter1. 35
36 A drawback of qualitative scenarios is that they do not, by definition, satisfy the 36
37 need for numerical information. Another disadvantage is that qualitative scenarios 37
38 aresometimesconsidered“unscientific”becausetheirassumptionsarenottranspar- 38
39 ent and the procedure for developing them is usually not reproducible. We address 39
40 these criticisms later in the chapter. 40
41 Quantitativescenarios,usuallybasedoncomputermodels,serveapracticalfunc- 41
42 tioninenvironmentalscienceandpolicybyprovidingnumericalresultswherethey 42
43 areneeded.Itcanbearguedthattheassumptionsofquantitativescenariosaremore 43
44 transparent than their qualitative cousins since these assumptions are expressed in 44
45 the form of model equations, inputs and coefficients that can be examined by any 45
46 trained observer. Although equations are not easily understood by everyone, the 46
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TheSASApproach:CombiningQualitativeandQuantitativeKnowledgeinEnvironmentalScenarios 125
1 assumptions are at least written down and perhaps are more accessible than the 1
2 undocumented and unspoken assumptions behind qualitative scenarios. After all, 2
3 most of the assumptions behind qualitative scenarios usually remain in the heads 3
4 of the stakeholders and experts that specify these scenarios. Another advantage of 4
5 quantitative scenarios generated from models is that these models are often already 5
6 published in the scientific literature and have therefore received some degree of 6
7 scientific scrutiny. 7
8 Inthefieldofenvironmentalscienceandpolicy,mostscenarioshavebeenquan- 8
9 titative because of the demand for numerical estimates of the future state of the 9
10 10
environment. From the perspective of scientific research, quantitative scenarios are
11 11
used as a research tool to investigate changes in the environment due to changing
12 12
drivingforces,e.g.,toestimatethefutureabilityofforeststotakeupCO fromthe
2
13 13
atmosphere under different intensities of future land use and forest management.
14 14
Most “inquiry-driven” scenarios, as described in Chapter 1 are quantitative.
15 15
From the perspective of policy development, quantitative scenarios express the
16 16
relationship between specific policies and their consequences on the environment.
17 17
Examples here are the quantitative scenarios that relate trends in sulfur and nitro-
18 18
gen air pollution emissions to changes in acidification in Europe (e.g. Alcamo et
19 19
al., 1990; Hordijk, 1991), greenhouse gas emissions to global climate change (e.g.
20 20
IPCC, 2001), and the release of a variety of gaseous chemicals with the depletion
21 21
of ozone in the upper atmosphere (e.g. WMO/UNEP, 1995, ?). These scenarios
22 22
provide concrete input to environmental policymaking because they indicate the
23 23
24 level of emission reductions required to protect the environment. They have also 24
25 influenced the selection of emission targets incorporated in international treaties. 25
26 While quantitative scenarios provide needed numerical data, a subtle disadvan- 26
27 tage is that the exactness of their numbers gives a false sense of knowing more 27
28 about the future than we actually do. A scenario estimate of 22 gigatons of carbon 28
29 dioxide emissions in 2100 could be interpreted to mean that we already know the 29
30 magnitude of emissions several decades from now. Another disadvantage is that the 30
31 computermodelsusedtogeneratethescenarioscontainmanyimplicitassumptions 31
32 about the future. Since models can only capture a part of the complex reality of 32
33 environmental problems, it has been argued that they represent a narrow point of 33
34 view about how the future will unfold, and in this way produce scenarios that are 34
35 unnecessarily narrow in view. An additional drawback is that the basics of model- 35
36 36
ing are difficult for the non-specialist to understand. Hence, the basic assumptions
37 37
behind the scenarios could be difficult to comprehend.
38 38
While it is useful to think about the advantages and disadvantages of qualita-
39 39
tive and quantitative scenarios, sometimes the distinction between them is blurred.
40 40
Qualitative scenarios can be derived by formalized, almost quantitative methods
41 41
(e.g.BunnandSalo,1993;Godet,2000),whilequantitativescenarioscanbedevel-
42 42
oped by soliciting numerical estimates from experts or by using semi-quantitative
43 43
techniques such as fuzzy set theory.2 Storylines can also be interspersed with nu-
44 44
45 45
46 2 SeeZarnowitz(1984)foradiscussionofapproachestosolicitnumericalestimatesoffutureconditionsfromexperts. 46
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126 J.Alcamo
1 merical data and thereby look both qualitative and quantitative.3 In these cases it is 1
2 better to speak of hybrid scenarios rather than one type or another. 2
3 Sincethereareadvantagesanddisadvantagestousingeitherqualitativeorquan- 3
4 4
titativescenarios,whichtypeshould beusedforaparticularscenarioexercise?The
5 5
challenge is to match the advantages of a particular scenario type with the func-
6 6
tion or purpose of the scenarios. In Chapter2, Alcamo and Henrichs suggestthree
7 7
main purposes for environmental scenarios: education and public information, sci-
8 8
entificresearch,anddecisionsupportandstrategicplanning.Atfirstglanceitwould
9 9
10 seem that the attributes of qualitative scenarios make them more appropriate for 10
11 education and public information, while quantitative scenarios are more appropri- 11
12 ate for scientific research, and both types could be used for decision support and 12
13 strategic planning. The accent is on more appropriate because it is not possible (or 13
14 14
necessary) to precisely match the type of scenario with its function. To complicate
15 15
matters, contemporary environmental studies (especially the more comprehensive
16 16
ones)havemanydifferentobjectives,someofwhichcanbebettersatisfiedbyqual-
17 17
itativescenariosandsomebyquantitativescenarios.Considerthescenarioexercises
18 18
19 that were part of major global environmental assessments of world water resources 19
20 (Rijsberman, 2000), global greenhouse gas emissions (Nakicenovic et al., 2000), 20
21 and world ecosystems (Carpenter et al., 2005). The goals of these exercises were 21
22 both scientific (What is the future state of the environment? What are the scien- 22
23 23
tificuncertaintiesinunderstandingtheenvironmentalsystem?)andpolicy-oriented
24 24
(What are emerging problems? What are the consequences of a continuation of
25 25
current policies? What can be done to protect the environment?).
26 26
Given this situation, how do we decide between qualitative or quantitative
27 27
28 scenarios? The answer from recent international scenario exercises is that we do 28
29 not need to decide. Rather, a combination of qualitative and quantitative scenarios can be 29
30 the best answer to achieving the goals of a scenario analysis. Some prominent cases in 30
31 which combined qualitative and quantitative scenarios were developed include the 31
32 32
World Water Vision scenarios of the World Water Commission (Cosgrove and
33 33
Rijsberman, 2000a), the SRES greenhouse gas emission scenarios of the Intergov-
34 34
ernmentalPanelonClimateChange(Nakicenovicetal.,2000),theglobalscenarios
35 35
of ecosystem services from the Millennium Ecosystem Assessment (MA, 2003;
36 36
Carpenter et al., 2005), and the global environmental scenarios of the Global
37 37
38 Environmental Outlook reports published by the United Nations Environment 38
39 Programme (UNEP, 2002, 2007). 39
40 We now briefly describe some of these exercises and discuss the general lessons 40
41 they offer to the practice of scenario analyses. 41
42 42
43 43
44 44
45 45
3 ThiswasthecaseforthestorylinesfromtheIPCCSRESscenariosofgreenhousegasemissions(Nakicenovicetal.,
46 2000)describedlaterinthisarticle. 46
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TheSASApproach:CombiningQualitativeandQuantitativeKnowledgeinEnvironmentalScenarios 127
1 1
3. The World Water Vision Scenarios – The World Water
2 2
Situation in 2025
3 3
4 4
5 The First World Water Forum in Marrakech, Morocco in 1997 was a huge 5
6 enterprise which brought together many private, governmental, academic and ad- 6
7 vocacygroups concernedwithworldwaterissues.One oftheimportant outcomes 7
8 of the Forum was the call for a “World Water Vision” to raise global awareness 8
9 about global water problems and solutions. The main objective of the Vision, and 9
10 the process to develop it, was to “convince the world of the urgency of the water 10
11 crisis and the need to involve many more people in development of water pol- 11
12 icy” (Cosgrove and Rijsberman, 2000a). It was declared that the Vision should be 12
13 expressed in the form of scenarios that describe the world freshwater situation in 13
14 14
2025.
15 15
The World Water Council set up two bodies to oversee the activities of the
16 16
World Water Vision and these groups also had a major influence on the develop-
17 17
ment of the World Water Scenarios. The first was a “Vision Management Unit”
18 18
which managed the day-to-day activities of the World Water Vision Exercise. The
19 19
second body was the World Commission on Water for the 21st Century consisting
20 20
mostly of water experts and decision makers. These two bodies set up a Scenario
21 21
Panel of 17 technical experts and stakeholders to provide the creative input to the
22 22
scenario construction. (The author of this chapter was a member of the Panel.)
23 23
Among many questions, the Panel had to decide whether to develop either
24 24
qualitative or quantitative scenarios. Some Panel members argued for qualitative
25 25
scenarios since the World Water Vision scenarios were intended to reach a large
26 26
public and therefore should be easy to communicate. Furthermore, it was thought
27 27
that qualitative scenarios could better reflect a wide range of views and opinions
28 28
aboutthefutureworldwatersituation.Otherpanelmembersmadeacaseforquan-
29 29
titativescenariosbecauseanimportantpartofthescenarios’audiencewasintended
30 30
to be the scientific and engineering community and they would expect numerical
31 31
estimates of the future world water situation. Moreover, the quantitative scenarios
32 32
could serve as a consistency check for the many views expressed in the qualitative
33 33
scenarios.
34 34
In the end, both qualitative and quantitative scenarios were developed. The
35 35
qualitative scenarios (storylines) described the unfolding of events related to the
36 36
future world water situation. They also identified the important factors directly
37 37
affecting the future world water situation (e.g. the future extent of irrigated land
38 38
39 or the level of water supply infrastructure), as well as those with an indirect affect 39
40 (e.g. the rates of population and economic growth). (An excerpt from a storyline 40
41 is given in Box 6.1). Meanwhile, the quantitative scenarios (model calculations) 41
42 reinforcedthestorylinesintwoways.First,modeloutputwasusedtoassesstheva- 42
43 lidity and consistencyofthestorylines,for example, tocheck ifthepopulation and 43
44 economic assumptions were consistent with statements about future levels of water 44
45 use. Second, they provided numerical information on water use and availability to 45
46 supplement the qualitative information contained in the storylines. 46
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128 J.Alcamo
Box6.1 Excerptofthe business-as-usualstoryline ofthe WorldWaterVisionscenarios.
1 1
Source: GallopinandRijsberman (2000).
2 2
3 3
The business-as-usual scenario assumes that following some setbacks caused by the
4 4
Asian and other regional financial crises, global economic growth resumes. Workers in
5 5
industrial countries who are displaced from traditional sectors use their entrepreneurial
6 6
skillstodevelopservicebusinesses.Aheightenedappreciationfortheneedtorehabilitate
7 7
and protect the environment increases demand for environmental services...
8 8
Theglobalpopulationcontinuestoincrease,reaching7.8billionpeopleby2025.More
9 9
than 80 percent of the world’s population – 6.4 billion people – live in developing
10 10
countries. Throughout the world, the population is older and more urban. About 84
11 11
percent of the population in industrial countries and 56 percent in developing countries
12 12
live in urban areas...
13 13
Per capita material and energy consumption increase as lifestyles throughout the world
14 14
become more like those in the North... Income inequality between and within rich
15 15
andpoorcountriesincreasestensions,butconflictsoversocialissuesthatdooccurremain
16 16
largely within national boundaries...
17 17
Insomeareaswithlimitedwaterandrapidpopulationgrowth,thedevelopmentofwater
18 18
infrastructure lags behind population growth, and the number of people without access
19 19
tosafewaterincreases.Inmostpartsoftheworld,however,economicgrowth,combined
20 20
with technological improvements, result in better living conditions, including increased
21 21
access to safe drinking water...
22 22
Estimates of increases in area of irrigated agriculture from 1995–2025 range from
23 23
5 to 10 percent globally. This slow-down in expansion rate for irrigation is due to
24 24
both a lack of investment funds and vigorous protests... that make most large dam
25 25
projects controversial... Water is used more efficiently, however, particularly in the
26 26
water-stressedareasoftheSouth.Thechangereflectstheuseofmoreefficientirrigation
27 27
systems, such as drip irrigation...
28 28
Increased technological efficiency and improved management prevent widespread dra-
29 29
matic water crises, but a number of regional crisis arise in some of the most arid
30 30
regions...
31 31
32 32
33 33
34 Thescenariosweredevelopedinaniterativefashion,startingwitha“zeroorder 34
35 draft” of a storyline crafted by the Scenario Panel, which was then convertedusing 35
36 best judgment into quantitative driving forces that could be used as model inputs. 36
37 Results from the modeling were used to update the storylines. The entire cycle of 37
38 developingorrevisingstorylines,specifyingquantitativedrivingforces,andrunning 38
39 39
the models was repeated twice.
40 40
When completed, the storylines and quantitative scenarios were posted on the
41 41
World Water Vision website and discussed at several regional meetings worldwide.
42 42
Commentswereincorporatedintothefinalstorylines.Threescenariosweredevel-
43 43
oped:
44 44
45 1. “Business-as-usual” (BAU) examines the consequences of continuing current 45
46 trends in population, economy, technology and human behavior up to 2025. 46
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TheSASApproach:CombiningQualitativeandQuantitativeKnowledgeinEnvironmentalScenarios 129
1 2. “Technology,Economics,andPrivateSector”(TEC)adoptsa“worldviewthat 1
2 is optimistic about the free market system (and) the potential of new technolo- 2
3 gies” (Rijsberman, 2000). 3
4 3. The “Values and Lifestyles”(VAL) scenario assumes “that a strong commitment 4
5 to avert a water crisis will emerge... with efforts focused on reaching a set of 5
6 global and regional targets. The emphasis is on... the importance of human 6
7 values” (Rijsberman, 2000). 7
8 8
More information about the development of the scenarios is given in Rijsber-
9 9
man (2000) and Alcamo (2001).
10 10
It can be argued that the scenarios fulfilled the goal of the World Water Vi-
11 11
sion exercise by helping to raise public awareness about water issues. They did
12 12
so by being an effective and credible method to communicate the main mes-
13 13
sages of the World Water Vision in numerous publications and public presentations
14 14
(CosgroveandRijsberman,2000b).Intheviewoftheauthor,thecombinedquali-
15 15
tative/quantitativeapproach was an important factor in the scenarios fulfilling their
16 16
goals. The qualitative storylines were an effective device for communicating with
17 17
thegeneralpublicandnon-experts,whilethequantitativecalculationsprovidedthe
18 18
hard numbers preferred by many scientists and water experts.
19 19
20 20
21 21
22 4. The SRES Scenarios of the IPCC – Global Greenhouse 22
23 Gas Emissions up to 2100 23
24 24
25 25
Around the same time as the World Water Vision exercise, another major
26 26
international effort wasgoing on to develop scenarios to betterunderstand the im-
27 27
plications of future climate change. To assess how climate change might affect river
28 28
runoff, forest growth, and the frequency of heat waves, as examples, it is necessary
29 29
to first compute the extent of future climate change with climate models. These
30 30
models require many inputs, in particular the future trend of greenhouse gas emis-
31 31
sions. Hence, emission scenarios play a central role in the study of climate change.
32 32
Moreover, estimates of future emissions are also needed by economists and engi-
33 33
neers as a basis for calculating the costs of mitigating climate change. Recognizing
34 34
their importance, the Intergovernmental Panel on Climate Change (IPCC) devel-
35 35
oped a set of greenhouse gas emission scenarios in 1992 (Leggett et al., 1992).
36 36
In January 1997 the IPCC appointed a “Writing Team” to develop new scenar-
37 37
ios based on recommendations of a 1995 evaluation panel (Alcamo et al., 1995).4
38 38
Since the Writing Team was supposed to produce a “Special Report on Emission
39 39
Scenarios,” the scenarios became known as the “SRES” scenarios.
40 40
There was no question that the scenarios would be primarily quantitative since
41 41
they were required as input to climate and economic models. However, the eval-
42 42
43 4 The Writing Team consisted of 28 Lead Authors (the author of this chapter among them) and an additional 26 43
44 ContributingAuthors.Sixmodelingteamsquantifiedthescenarios.Thehugenumberofactorswouldhavebeenan 44
unwieldynumberhadtheyallactivelyparticipatedinthescenariodevelopmentandreportwriting.Asitwas,meetingsof
45 45
theWritingTeamweretypicallyattendedbyaround10to15authors,andonlysmallnumbersofauthorswereactivein
46 allphasesofthereportwriting. 46
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130 J.Alcamo
1 uators of the earlier IPCC scenarios (Alcamo et al., 1995) made specific recom- 1
2 mendations on how to develop these scenarios: (i) they should be developed by an 2
3 “open” procedure that embraced a wide range of viewpoints of experts and inter- 3
4 est groups, (ii) they should be checked for consistency with knowledge about the 4
5 driving forces of emissions, (iii) the assumptions of the driving forces of emissions 5
6 should be stated explicitly so that economists and other analysts could better assess 6
7 future costs of emission reductions. These recommendations led to the strategy of 7
8 developing both storylines and model-based scenarios. 8
9 Although the SRES scenarios have the same two basic elements as the World 9
10 WaterVisionscenarios,namelystorylinesandmodelcalculations,theirimportance 10
11 is reversed. In the World Water Vision scenarios, the storylines were the main 11
12 vehicle for carrying the scenario message while model calculations played a sup- 12
13 porting role. In the SRES scenarios, the model calculations were more important 13
14 because the main objective of the scenarios was to produce numerical estimates of 14
15 future emissions. Meanwhile, storylines provided a supporting role, mainly to ex- 15
16 plain the logic of selecting the driving forces of emissions. In the SRES scenarios 16
17 each storyline expressed a different view of future world development, especially 17
18 in the degree of globalization versus regionalization, in the relative emphasis on 18
19 economic growth, and in the level of environmental protection. For example, the 19
20 storylineofscenariofamily“A1”described afutureofrapid technologicalprogress 20
21 and economic prosperity (see excerpt in Box 6.2). Based on this logic the sce- 21
22 nariodevelopersselectedappropriatenumericalestimatesofdrivingforcesoffuture 22
23 emissions, such as trends in population, economic growth, and land use distribu- 23
24 tion. These and other driving forces were used as input to six different models for 24
25 producing estimates of the emissions of all important greenhouse gases and related 25
26 substances. 26
27 The resulting scenarios were clustered into four scenario “families” made up of 27
28 groups of individual scenarios. This hierarchical organization of scenarios and sub- 28
29 scenarios was one of the traits that distinguished the SRES from the World Water 29
30 Vision scenarios. Using the description from the SRES report (Nakicenovic et al., 30
31 2000), the scenarios consisted of: 31
32 • The A1 storyline and scenario family describing a future world of very rapid 32
33 33
economic growth, low population growth, and the rapid introduction of new
34 34
and more efficient technologies.
35 • The A2 storyline and scenario family describing a very heterogeneous world. 35
36 36
The underlying theme is self-reliance and preservation of local identities.
37 • The B1 storyline and scenario family describing a convergent world with the 37
38 38
same low population growth as in the A1 storyline, but with rapid changes in
39 39
economicstructurestowardaserviceandinformationeconomy,withreductions
40 40
in material intensity, and the introduction of clean and resource-efficient tech-
41 41
nologies.
42 • The B2 storyline and scenario family describing a world in which the emphasis 42
43 43
is on local solutions to economic, social, and environmental sustainability.
44 44
45 The SRES scenarios were successful in that they provided a consistent set of 45
46 assumptions for computing global climate change and for assessing climate change 46
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TheSASApproach:CombiningQualitativeandQuantitativeKnowledgeinEnvironmentalScenarios 131
Box6.2 Excerptof theA1storyline from theIPCC-SRESscenarios.
1 1
Source: Nakicenovicetal.(2000).
2 2
3 3
In the A1 scenario family, demographic and economic trends are closely related, as
4 4
affluenceiscorrelatedwithlonglifeandsmallfamilies(lowmortalityandlowfertility).
5 5
Global population grows to some nine billion by 2050 and declines to about seven
6 6
billion by 2100...
7 7
Theglobaleconomyexpandsatanaverageannualrateofabout3%to2100... While
8 8
the high average level of income per capita contributes to a great improvement in the
9 9
overallhealthandsocialconditionsofthemajorityofpeople,thisworldisnotnecessarily
10 10
devoid of problems. In particular, many communities could face some of the problems of
11 11
social exclusion encountered in the wealthiest countries during the 20th century...
12 12
Energy and mineral resources are abundant in this scenario because of rapid technical
13 13
progress, which both reduces the resources needed to produce a given level of output and
14 14
increases the economically recoverable reserves. Final energy intensity (energy use per
15 15
unit GDP) decreases at an average annual rate of 1.3%.
16 16
With the rapid increase in income, dietary patterns shift initially toward increased con-
17 17
sumption of meat and dairy products, but may decrease subsequently with increasing
18 18
emphasis on the health of an aging society. High incomes also translate into high car
19 19
ownership, sprawling suburbs, and dense transport networks...
20 20
21 21
22 22
23 and its impacts in different countries and regions in the world.5 These studies in 23
24 turn have influenced discussions about global and national climate policies. 24
25 In conclusion, the quantitative aspects of the SRES scenarios provided the nu- 25
26 merical information needed for climate analysis and were able to pass through the 26
27 very vigorous scientific and political review process of the IPCC. Meanwhile the 27
28 qualitativestorylinesprovidedaneffectiveformatforunderstandingtheassumptions 28
29 of the scenarios. 29
30 30
31 31
32 32
5. The Scenarios of the Millennium Ecosystem
33 33
Assessment – The State of World Ecosystems up to
34 34
2050
35 35
36 36
37 While the World Water Vision and IPCC-SRES scenario exercises were 37
38 windingdown,anothermajorinternationalexercisewasjustgettingunderway,this 38
39 time with a focus on global ecological systems. The scenario development of the 39
40 “Millennium Ecosystem Assessment (MA) was part of a huge effort to assess world 40
41 ecosystems, officially launched by the Secretary-General of the UN, Kofi Annan 41
42 in 2000. The MA aimed to support decision makers involved with three land- 42
43 markconventionsfromthe1990srelatedtoworldecosystems–theDesertification, 43
44 44
5 TheSRESscenarioshavenotonlybeenusedasbasicinputforrunningglobalclimatemodels,buthavealsobeenused
45 45
instudiesofglobalwateruseandavailability(e.g.Alcamoetal.,2007a)andregionalclimateimpactEurope(e.g.Arnellet
46 al.,2003). 46