ScenariosEmily McKenzie

2 April, InVEST Introductory Seminar, Bangkok

Outline

• What are scenarios?• Why use scenarios?• How to develop scenarios?• Some examples

Tell Stories, Use Scenarios

Valuation study in Bermuda

After

Before

Total values often less meaningful

• Bermuda’s reefs worth– $722 million p.a.– 10-17% of GDP

But what would be costs and benefits of new shipping channels?

What are scenarios?

• Plausible, simplified, descriptions of future

• Based on coherent & consistent assumptions:

– key drivers– their relationships– their impacts on

ecosystems

Despite their importance, environmental services are not normally included in resource decisions.

This is sometimes because it is hard to compare the benefits and costs of different options.

Why Use Scenarios?

Types of scenarios

• Interventions– Designs for policies, plans and projects

• Explorations– Possible but unexpected futures

• Visions– Perceptions of desirable or undesirable futures

• Projections– Depictions of the expected future

Yesterday

Today Tomorrow

The Future?

Interventions

Depictions of how additional, new interventions could be implemented, such as policies, projects or plans.

Explorations

• Explore possible future developments. • Anticipate unexpected future circumstances, test how policies cope with change.

Visions & Projections

Visions: Subjective depictions of possible futures that vary according to their desirability.Projections: Depictions of the expected future, without new interventions

Why use scenarios?

• Identify tradeoffs• Consider new policies• ‘Future-proof’ policies• Air conflicts, develop consensus• Learning• Storytelling

Scenarios for InVEST

• Scenarios as maps of land cover and/or coastal and marine habitats and uses.

• Scenario maps feed into InVEST to produce maps of ecosystem services for each scenario.

Example from Tanzania

Hopeful Expectations – poverty alleviation

Business as Usual

Example from Tanzania

Carbon storage on the current landscape…

Conservation 2025

Current

BAU 2025

Confidential draft, Feb 2009Thanks to Dr Ruth Swetnam

Comparison of carbon storage and sequestration in different scenarios…

2000 Conservation2025

BAU 2025

2.419 t/C

-8.65 7 t/Cor -3.6% of 2000 value -31.617 t/C

or - 13% of 2000 value

LOSS LOSS

Confidential draft, Feb 2009Thanks to Dr Ruth Swetnam

Scenario Development Methods

Bringing together multiple methods:• Qualitative: narrative stories of future

– Multi-stakeholder community visioning– Hand-drawn maps

• Quantitative: numerical estimates of future– Landscape optimization modeling – Computer-based land transition models

Drivers• any natural or human-induced factor that directly or

indirectly causes a change in an ecosystemRules• principles or conditions that prescribe how changes will

occur in the future

Others • Timeframe• Spatial scale & extent

Key Elements

Methods in Tanzania

– High stakeholder participation– Multiple stakeholder workshops, interviews– Time: 1 year – Capacity: 2 coordinators– Policy review

Step 2: Select the right scenario approach

Step 3: Develop scenario storylines

Step 4: Create scenario maps

Step 5: Assess ecosystem service outcomes

Step 6: Use and communicate results

Step 1: Understand scenarios

Key steps

Characteristics of effective scenarios

• Relevant• Legitimate• Plausible• Understandable• Distinct• Surprising• Scientifically credible• Comprehensive

• Iterative• Participatory

Photo credit: Josh Goldstein

• Scenario Development Guide– Picking the right scenario– Creating storylines, turning storylines into maps– NatCap case studies

• Scenario Generator – Simple, rule-based approach– % change from storylines

• InSEAM– Online collaborative map drawing software

• IDRISI Land Change Modeler– Around a dozen land cover transitions– Rules and constraints, taking into account historical trends

NatCap scenario tools

Central Sumatra Today

Sumatra Ecosystem

Vision

Government spatial plan

Sumatra

(60% more forest than

2008)

Same amount of natural

forest as 2008 (but likely

worse)

Hawaii

Issues of concern:-Effects of forestry and other industrial activities on aesthetic views-Effects of shellfish harvest and aquaculture on sensitive habitats

Any questions?

Scenario exercise #1

• Select one priority opportunity for InVEST to inform decisions in the GMS.

• Which services would you assess?

• Describe the scenario storylines you would compare in InVEST.