Causality Chain · Audit Detail

Climate Migration Threshold — Bangladesh/Sahel

climate_refugees_threshold · order-4 · AP HuG subtopic 2.7 · status rated

Composite 10.33 / confidence high

Grade B: 3 sources, source_quality_avg=4.33, corroboration=1, claim_strength=3, geo_specific=1, counter_evidence_handled=no.

The historical event

Climate Migration Threshold — Bangladesh/Sahel · 2009 · Bangladesh delta + Sahel

Cyclone Aila 2009 displaced 200K Bangladeshis; Sahel desertification displaced 1.5M+ 2000-2020; IPCC AR6 documented as climate-attributable.

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Card(s): — (threshold-only)

Conditions: —

Threshold: {'global_plays_geq': {'green_revolution': 3}}

Type: spawn_event_card_in_all_hands

Payload: {'card_id': 'climate_migration', 'card_type': 'event'}

Target: all_players

Delay turns: 4

Dimension	Score
Source quality (avg)	4.33
Corroboration (independent sources)	1
Causal-claim strength	3
Counter-evidence handling	0
Geographic specificity	1
Temporal scope	1

Black, R. et al., 'The effect of environmental change on human migration', Global Environmental Change 21S1 2011

Type: peer_reviewed · Year: 2011 · Geography: Global

Conceptual + empirical framework for environmental migration drivers; widely cited.

IPCC AR6 WG II Chapter 8: Poverty, Livelihoods and Sustainable Development, 2022

Type: gov_dataset · Year: 2022 · Geography: Global

Climate-attribution analysis of migration in Bangladesh, Sahel, Pacific Islands; consensus authoritative source.

Internal Displacement Monitoring Centre (IDMC), 'Global Report on Internal Displacement 2020'

Type: gov_dataset · Year: 2020 · Geography: Global

Quantified disaster-displaced populations 2008-2020; 280M+ cumulative climate-related displacements.

No counter-evidence noted. Trellison reserves the right to escalate this chain to "needs counter-evidence review" if challenges emerge.

Audit ID: af576b4a7414417e8260f2d0f7108e54

Audit date: 2026-05-14T05:54:32.088392+00:00

Protocol version: v1.0

Rater: claude_sprint2_auto

Corroborating independent count: 1