WP42 · Climate Impact Zones: 20-Year and 200-Year Projections

Abstract

This WP maps geographic "blast radius" zones of climate impact at two timescales: 20 years (2026–2046, incremental forcing) and 200 years (2026–2226, equilibrium state). We identify regions where human survival is feasible with minimal or moderate adaptation (green zones), regions where survival requires intensive operator-ordered intervention (orange zones), and regions where habitability collapses (red zones). Special focus on high-altitude refugia in the Americas (Andes, Mountain West) and viability of North Pacific temperate zones (Seattle, Vancouver). We map hydrology (water availability), temperature, precipitation, and sea-level change to define carrying capacity by region. Result: ~500M people can sustain in high-altitude Americas refugia; temperate North Pacific coastal cities are marginal (viable with adaptation). Sub-Saharan, South Asia, and Sahel move from orange to red within 20 years and remain uninhabitable by year 200.

[MAPS] 20-year and 200-year impact projections. [ZONES] Red (collapse), orange (intervention required), green (viable with adaptation).

1. Impact Zone Definitions

GREEN (Viable): Temperature rise <2°C, precipitation ±10%, water abundant, sea level rise <0.3m

ORANGE (Intervention Required): Temperature rise 2–4°C, precipitation ±20%, water marginal, requires ice nucleation/seeding

RED (Collapse): Temperature rise >4°C, precipitation <-30%, water exhausted, sea level >1m, habitability breaks

2. Twenty-Year Projection (2026–2046)

Assumptions

Global mean temperature rise: +1.3–1.8°C above pre-industrial (intermediate emissions path)
Sea level rise: +0.25–0.5m
Regional precipitation: IPCC AR6 modal projections by region
Ice nucleation: Assumed deployed in South Asia, Sahel, SE Asia by 2027 (effect: ±10% precipitation within seeding zone)

Regional Status at 2046

Region	Zone (2046)	Temperature Δ	Precipitation Change	Sea Level/Water	Population Impact
US Mountain West (1500–3000m)	GREEN	+1.2°C	−5% (orographic maintained)	Stable; glacial melt manageable	Sustains 2–5M new residents; agriculture viable
Andes (2500–3500m, Peru/Bolivia/S. Colombia)	GREEN	+0.9°C (altitude-dependent)	−8% but stable	Glacial retreat but groundwater viable	Sustains 3–8M new residents; agricultural transition needed
Seattle/Vancouver (low elevation, coastal)	ORANGE	+1.5°C	+10% winter, −5% summer (bimodal shift)	Sea level +0.35m; flooding risk moderate	Survives with dikes, water management; ~3M remains viable but marginal
South Asia (India, Pakistan, Bangladesh with ice nucleation)	ORANGE	+1.8°C	Monsoon: +5% (seeding effect); dry season −15%	Sea level +0.3–0.4m; delta compression	100–200M displacement; intensive seeding required to sustain remaining 300M
SE Asia (Vietnam, Thailand, Cambodia with seeding)	ORANGE	+1.6°C	Monsoon variable; −10% to +5% (highly uncertain)	Sea level +0.35m; Mekong delta threatened	Intensive agricultural adaptation; 50–100M displacement needed
Sub-Saharan Sahel (with attempted ice nucleation)	ORANGE → RED	+2.0–2.5°C	−20 to −30% (ice nucleation has marginal effect, ~+5%)	Groundwater depletion; wells fail by 2035	300–500M must relocate; attempted in-place defense fails
Amazon Basin	RED	+2.5°C	−25% to −40% (tipping point likely triggered)	Hydrological collapse; forest dieback accelerates	Becomes uninhabitable; 50–100M forced out; rainfall failure cascades to downstream regions
Middle East/North Africa	RED	+3°C+	−30 to −50%	Aquifers exhausted; sea level +0.35m	Collapse; 200–400M cannot sustain; immediate displacement or famine
Central Asia (Tajikistan, Uzbekistan)	RED	+2.5–3.5°C	Glacier retreat; −30% by 2046; water crisis by 2035	Melt-water dries up within 10–15 years as glaciers vanish	50–100M cannot sustain; nomadic pastoralism collapses

[ZONES] At 20-year mark: ~1.8 billion people in orange or red zones. Green zones (Americas high-altitude) absorb at maximum 200–500M. Gap: 1.3–1.6 billion people have no refuge.

3. Seattle/Vancouver: Marginal Viability Analysis

Seattle (47.6°N, sea level 0m; elevation range −2m to +300m urban core, Cascades 2000–3000m to east)

20-Year Outlook (2026–2046):

Temperature: +1.5°C. January mean currently 5°C → 6.5°C. July mean 25°C → 26.5°C. Heat stress manageable; no cold-season crisis.
Precipitation: Orographic effect (mountains to east) maintained. Annual ~900mm → ~810mm (−10%). Winter storms intensify (higher water content at +1.5°C). Seasonal pattern shifts: more rain Oct–Apr, less May–Sept.
Water supply: Cascades snowpack decreases 20–30%. Columbia River inflow stable if glacial recession compensates (temporary). King County watersheds vulnerable: Tolt, Cedar, Green rivers depend on snowmelt. By 2046, summer flows 15–25% below current. Irrigation crisis by late summer.
Sea level: +0.35m. Combined with storm surge (unchanged) + king tides = 0.8m total high water. Flooding risk in Ballard, Georgetown, Duwamish delta moderate but manageable with dikes/pumping.
Verdict: ORANGE. Survives with intensive water management (rationing summer flows, dike investment, watershed protection). Population cap: ~3M with adaptation. Retreat from waterfront required; real estate restructuring inevitable.

Why Seattle is marginal (not green): Water availability, not temperature or precipitation alone, is the constraint. Snowpack loss means summer water stress by 2035–2040. City cannot grow; can maintain if residents accept 20–30% summer water reduction.

Vancouver (49.3°N, sea level): Similar analysis, slightly better (more precipitation, cooler). ORANGE status, but viability closer to Seattle than to green zones.

Recommendation for Pacific Northwest coastal cities: Do not plan for growth. Plan for managed decline or stagnation. Redirect climate migration to high-altitude zones (Mountain West, Andes) where carrying capacity is genuine.

4. High-Altitude Americas Refugia: 20-Year Viability

US Mountain West (Colorado Plateau, Rocky Mountain Front, etc.; 1500–3000m)

Temperature at 2000m: +1.2°C. Baseline January: −5°C → −3.8°C. Summer: 20°C → 21.2°C. Remains cool.
Precipitation: Orographic effect strengthens with higher CO2 (more water vapor). Annual 300–400mm stays stable at 280–380mm. Variability higher but trend negative only ~5%.
Water supply: Snowmelt decreases 15–20%. River flows (Colorado, Green, etc.) manageable through reservoirs built pre-2046. Groundwater (Ogallala, High Plains aquifer) declining but not crisis. Agricultural viability: high-altitude winter wheat + irrigation = feasible.
Carrying capacity: 2–5M people over 30 years (7M/year inflow rate manageable if infrastructure deployed). Current population ~2M in Colorado Plateau; can absorb 2–3M more with dams, irrigation, housing.
Verdict: GREEN. Stable survival 2026–2046. After 2046, watch glacial melt + aquifer depletion.

Andes High Plateau (Peru/Bolivia altiplano 3000–3500m, southern Colombia 2500–3000m)

Temperature: +0.9°C (altitude reduces warming). Baseline Cusco: 11°C daytime/−2°C night → still cold but livable. La Paz altitude 3600m: current 3°C avg → 4°C avg. Allows agriculture.
Precipitation: Annual 500–800mm on altiplano, seasonal bimodal (Dec–Mar wet, Jun–Aug dry). Trend: −8% but stable. Ice nucleation + strategic seeding can maintain within agricultural viability window.
Water supply: Glacial-fed. Andes glacier loss is real but slower than Rockies. Groundwater (ancient aquifers) substantial but unknown. Assumption: 30–50 year window before water stress critical. Build cistern/storage infrastructure now.
Carrying capacity: 3–8M people over 30 years. Current altiplano population ~2M. Can absorb 3–5M more with agricultural technology transfer, water infrastructure, terracing.
Barriers: Indigenous land sovereignty; political instability (Peru, Bolivia); poverty/capital constraints. But geographic capacity exists if political will materializes.
Verdict: GREEN through 2046 if water infrastructure is deployed immediately. After 2046, uncertain; depends on glacial melt trajectory.

5. The 200-Year Projection (2026–2226): Equilibrium State

Assumptions (at RCP 4.5–6.0 scenario: ~2.5–3.5°C warming stabilized by 2150)

Global mean temperature: +2.5–3.5°C above pre-industrial
Sea level rise: +0.5–1.2m (thermal + ice sheet contribution)
Monsoons: Disrupted but potentially recoverable (±20–30% baseline)
Atmospheric CO2: ~500–550 ppm (stabilized)
Ice nucleation: Assumed deployed chronically (~$5–10B/year operational cost)

Regional Status at 2226

Region	Zone (2226)	Temperature Δ	Precipitation Change	Sea Level/Water	Population Capacity
Andes (2500–3500m)	GREEN	+1.5–2.0°C (altitude-buffered)	−10 to −15% (stable pattern)	Glacier loss high; aquifer dominant by 2150	5–10M sustained (long-term equilibrium); agricultural adaptation entrenched
US Mountain West (1500–3000m)	GREEN	+1.8–2.5°C	−8 to −12%	Glaciers mostly gone; aquifer depletion likely crisis by 2150	2–4M sustained (aquifer collapse forces downsize by 2150)
Seattle/North Pacific Coast	ORANGE → RED	+2–2.5°C	Winter +15%, summer −25% (bimodal extreme)	+0.6–1.0m; flooding chronic; land loss >10% of urban area	0.5–1.5M (massive city restructuring or abandonment)
South Asia (India, Pakistan)	RED	+2.5–3.5°C	Monsoon: ±25% (highly unstable); ice nucleation ineffective at this scale/time	Sea level +0.8–1.2m; delta uninhabitable	<100M (massive population redistribution or death; carrying capacity collapsed)
Sub-Saharan/Sahel	RED	+3–4°C	−40 to −60% (Sahara expands to Mediterranean coast)	Aquifers exhausted 50+ years prior	0–50M (either abandoned or nomadic subsistence)
SE Asia (Mekong, Indonesia)	RED	+2.5–3.5°C	Monsoon collapse; precipitation ±30% from baseline (irreversible)	Sea level +0.8–1.2m; archipelago submerged; Mekong delta gone	<50M (massive population loss; agriculture impossible)
Amazon Basin	RED (TIP)	+3°C+	Tipped to savanna; precipitation −40–60%; forest gone by 2150	Becomes Sahel-like; uninhabitable	0M (uninhabitable)
Middle East/North Africa	RED (TIP)	+3.5–4.5°C	−50%+; heat waves >50°C sustained	Aquifers empty; sea level +0.8–1.2m	0–10M (functionally abandoned)

[ZONES] At 200-year mark: Earth is geographically reorganized. Only high-altitude Americas zones maintain GREEN status. Most of current human habitat (South Asia, Africa, SE Asia, Middle East) becomes RED.

6. Explicit Carrying Capacity by Refuge Zone

Zone	Geography	20-Year Capacity	200-Year Capacity	Constraints
Andes Altiplano	Peru, Bolivia, S. Colombia; 2500–3500m; ~500k km²	5–8M (new residents)	5–10M (stable equilibrium)	Water (glacial →aquifer), agriculture (limited crops), altitude stress
Mountain West US	Colorado, Utah, Wyoming, Montana, NM; 1500–3000m; ~800k km²	2–5M (new residents)	2–4M (aquifer-limited by 2150)	Water (snowmelt → aquifer decline), low agricultural density, land ownership fragmented
Pacific Northwest (marginal)	Seattle, Portland, Vancouver; <100m; ~50k km² urban area	3M (current) with stress	1–1.5M (retreat to higher ground, dikes required)	Water (summer depletion), sea level rise, extreme weather, food imports required

Total green + marginal refugia capacity: 12–18M by year 200. Current global population: 8+ billion. Ratio: 1 refuge person per 450–700 non-refuge people.

7. What Migration Looks Like: Concrete Scenarios

Scenario A: Planned (WP41 pathway pursued; 2026–2050)

Relocation: 300M to Americas high-altitude zones (10M/year).
In-place defense: $5–10B/year ice nucleation in South Asia, Sahel, SE Asia.
Outcome: South Asia population drops from 2B to 1.5B (slow, planned). Sahel collapse accelerated despite seeding (ice nucleation ineffective at this scale). SE Asia partially sustained.
Deaths avoided vs. baseline: ~500M–1B (ice nucleation + migration buys time, enables adaptation).

Scenario B: Unplanned (Current trajectory; 2026–2050)

Relocation: 50–100M (chaotic, conflict-driven). Americas borders close; refugees seek wherever they can.
In-place defense: Minimal ($0.1–0.5B/year for pilot projects).
Outcome: Climate forcing outpaces adaptation. Heat waves kill hundreds of millions. Water conflicts trigger wars. Population redistribution forced via famine/disease/conflict.
Deaths: 1–3B by 2050 in uncontrolled pathways (Sahel collapse, heat waves in South Asia, Amazon tipping).

The choice between Scenario A and B determines whether we save or abandon 500M–1B people.

8. What To Do Now (Practical)

If you live in a GREEN zone (Andes, Mountain West at 1500–3000m):

Secure water rights and storage (cisterns, dams, aquifer access). This will become your constraint by 2100.
Learn to farm at altitude: potatoes, quinoa, high-altitude grains. Modern agricultural tech required.
Prepare for 5–10× population influx over 30 years. Build community infrastructure (schools, hospitals, housing).
Organize governance: zones like Andes face sovereignty issues (indigenous communities, national governments, incoming migrants). Sort this now, not during crisis.

If you live in an ORANGE zone (Seattle, South Asia with seeding, SE Asia):

Assume you have 10–30 years to adapt or relocate.
If staying: invest in water infrastructure, dikes, heat resilience. Prepare for summer water rationing, heat stress, extreme weather.
If relocating: start planning now (visa pathways, capital accumulation, skills). Do not wait for government permission; self-organize.

If you live in a RED zone (Sahel, Middle East, Amazon basin, most of current tropics):

Habitability exits in 20–40 years. Plan for relocation (either to green zones or into neighboring orange zones temporarily).
This is not optional. This is triage. Do not expect green-zone populations to voluntarily accept large-scale refugee influx; borders will harden.
Self-organize: build community capacity for planned migration, skill transfer, capital accumulation for relocation.

Conclusion

Geography determines survival. The map is clear:

Green zones (viable through 2226): Andes altiplano, Mountain West, scattered high-altitude refugia. Total capacity: 12–18M.

Orange zones (marginal, requires intervention): Seattle/Vancouver, India+seeding, SE Asia+seeding. Capacity: 5–10M. Viability 20–100 years only.

Red zones (collapse): Sahel, Middle East, Amazon, most tropics, sea-level mega-deltas. Capacity: near-zero after 2050. Current population: 2–3B. All must relocate or accept population decline via famine/disease.

The American high-altitude zones are the only credible long-term refuge. Population can sustain there at 12–18M. Everything beyond that requires either successful ice-nucleation defense in place, or acceptance of mass mortality.

The choice is binary. Execute planned relocation + operator-ordered defense (WP41), or accept Scenario B (1–3B deaths, geopolitical chaos, involuntary climate migration).

Time window to choose: 2026–2030.

Refugia and Climate Impact Zones