Solarpunk Liberalism: Gaia Factor on Primary Residence

Using Modifications to Property Tax to Start the Solarpunk Path of Governance | Chapter 2

Aug 28, 2025

The spark of inspiration for this chapter was this substack post: The Leviathan: Property Taxes in the Big Apple, by Stephen Hoskins. Since property taxes are among the most direct tools available to local governments, they should also serve as the starting point for Solarpunk Liberalism.

Most property tax systems are based on land value alone. I propose we keep that principle but change the equation. In addition to land value it will incorporate ecological impact and building materials.

The purpose of these measures is to redirect consumer habits instead of primarily targeting businesses. Policies often increase costs for companies, but by influencing consumer behavior, we create pressure on businesses to adapt. Over time, shaping individual choices is likely to drive broader structural change.

Some relevant reads:
1. Achieving Sustainability: The Stick or the Carrot? | INSEAD Knowledge
2. Green Incentives That Resonate with Modern Consumers - Reward the World™
3. Carrot and stick: The competitiveness of sustainability - Foresight
4. Economic Incentives | US EPA
5. Frontiers | Which is More Effective: The Carrot or the Stick? Environmental Policy, Green Innovation and Enterprise Energy Efficiency–A Quasi-Natural Experiment From China

Nomenclature

Gaia Factor (GF) - The Gaia Factor is calculated according to a dwelling's Ecological Impact and Building Materials. The Gaia Factor is the percentage of tax exemption applied to the base property tax.
Ecological Impact (EI) - This variable accounts to 50% of the Gaia Factor. An already built object might not be able to switch building materials, but action can be taken so as to get a 50% tax exemption, if one gets a perfect score on Ecological Impact alone.
Building Materials (BM) - The remaining 50% of the Gaia Factor. A simple number representing the sustainability of building materials used.

Gaia Factor on Property Tax

1. Base Property Tax

The Base Property Tax will be based on a local territory’s traditional Property Tax system. Unoccupied or unused buildings and non-utilized land will face a modest tax increase, balanced in that way so that owners generally accept the higher cost without being compelled to sell the property. This increase will follow a graduated schedule that rises progressively the longer a property remains unused, incentivizing productive utilization while not creating pressure for forced sales.

2. Gaia Factor Calculation

The Property Tax will be adjusted to account for the Gaia Factor (GF). Each year, an updated ideal GF will be determined based on the ecological needs of the property’s location, and this value will influence the tax calculation. Because environmental priorities vary by region, the GF will differ accordingly. For example, a dry region might place greater emphasis on Rainwater Collection, while an area with abundant rainfall might not. The following variables are examples illustrating how the system could adapt to specific ecological contexts.

EI Variable Scores:
- Rainwater Catchment Score 0.4
- Green Roof Score 0.3
- Garden Utilization Score 0.3
Ecological Impact (50%)
- The Rainwater Catchment Score is calculated using a simple formula based on:
  Building Footprint Area (m²)
  Average Annual Rainfall (mm) for the region
  Installed Rainwater Harvesting Capacity (liters)
  
  Formula:
  Rainwater Score = (Installed Tank Capacity/(Building Footprint x Annual Rainfall)) x 0.4
  - Example:
    Building Footprint → 10 x 10 = 100m²
    Average Annual Rainfall → 680mm
    Ideal Capacity → 100 x 680 = 68,000l
    Installed Tank → 20,000l
    
    Score = 20,000/68,000 x 0.4 = 0.1176
- The Green Roof Score depends on coverage and vegetation.
  Coverage Calculation:
  Full score achieved when Green Roof Area = 50% of Building Footprint.
  
  Formula:
  Coverage Ratio = Green Roof Area/(0.5 x Building Footprint)
  
  Vegetation Type Multiplier:
  Ground Plants (lawn, sedum, mosses) → 0.4
  Medium Vegetation (shrubs, small plants) → 0.7
  High Vegetation (trees) → 1.0; if at least one tree is present, 1.0 is applied, even if the lawn dominates.
  
  Formula:
  Green Roof Score = Coverage Ratio x Vegetation Multiplier x 0.3
  - Example:
    Building Footprint → 100m²
    Green Roof → 50m²
    Vegetation → sedums and mosses only
    
    Coverage Ratio = 50/0.5 x 100 = 1
    Green Roof Score = 1 x 0.4 x 0.3 = 0.12
- The Garden Utilization Score (GUS) measures how effectively garden space contributes to carbon sequestration and ecological health, relative to the size of the available garden.
  Garden Area = Property Area - Building Footprint
  Each portion of the garden is expressed as a percentage of the total garden area:
  Paved Area → -0.004 per 1% of garden
  Lawn → +0.001 per 1% of garden
  Vegetables/Shrubs → +0.003 per 1% of garden
  Tree → +0.015 each
  
  Formula:
  GUS = (P% x -0.004) + (L% x +0.001) + (V% x +0.003) + (T x 0.015)
  Capped at 0.4 (full) score.
  - Example:
    Property Size = 150m²
    Building Footprint = 100m² → Garden = 50m²
    Garden Usage:
    20m² Paved (40%)
    5m² Grass (10%)
    25m² Veg/Shrubs (50%)
    5 Trees
    GUS = (40 x -0.004) + (10 x +0.001) + (50 x +0.003) + (5 x 0.015)
    GUS = -0.016 + 0.01 + 0.15 + 0.075
    GUS = 0.309
Total EI Score:
EI score: Rainwater Score + Green Roof Score + GUS
EI score = 0.1176 + 0.12 + 0.309 = 0.5466

Building Materials (50%)
- Conventional (reinforced concrete, cement blocks or fired clay bricks etc.) → High embodied carbon, energy-intensive, non-renewable → 0.10
- Autoclaved Aerated Concrete → Lower density but still cement-based → 0.25
- Standard Timber → Moderate embodied energy, possibly unsustainable sourcing → 0.40
- Straw Bale (plastered) → Renewable, good insulation, minor processing required → 0.60
- Natural Stone (locally sourced) → Durable and recyclable, but high transport impact if not local → 0.75
- Recycled Brick/Stone/Timber → Diverts waste, no new raw materials → 0.85
- Rammed Earth → Local soil, minimal processing, very low embodied energy → 0.95
- Mudbrick / Adobe → Sun-dried, zero firing and renewable → 1.00
Gaia Factor and Final Property Tax Calculation:
- Final Property Tax = Old Property Tax x (1 - GF) →
  Final Property Tax = Old Property Tax x (1 - ((EI + BM)/2))
  - Example 1:
    Old Property Tax = $102
    EI Score = 0.5466
    BM Score = Conventional = 0.1
    
    102 x (1 - ((0.5466 + 0.1)/2)
    102 x (1 - 0.6466/2)
    102 x (1 - 0.3233)
    102 x 0.6767
    $69.02

3. Primary MEI Generation

As mentioned in the first chapter, the primary way of generating MEI occurs at the primary residence. These MEI are minted proportional to the Gaia Factor. Each municipality will have its own base MEI generation number, based on factors such as targeted average SEAP uses per day, monthly service capacity, average resident scores, etc.

Base MEI Generation
- The following illustrates an imagined formula whose variables can and should vary depending on local necessity.
- Variables:
  u = Average SEAP uses per day
  s = Monthly Service Capacity
  GF = Average Gaia Factor score per person
  M = Monthly Minting Budget
  p = Resident Population
  d = Days per month
  - Example:
    u = 3 (each resident can access 3 SEAPs per day if they have a perfect Gaia Factor)
    p = 96,000 (total population)
    GF = 0.4 (average Gaia Factor)
    d = 30 (days per month)
    
    Step 1 - Calculate total monthly SEAP uses capacity:
    s = p x u x d = 3 x 96,000 x 30 = 8,640,000
    
    Step 2 - Calculate MEI per person:
    MEI = s/(p x GF) | 8,640,000/(96,000 x 0.4)
    MEI = 8,640,000/38,400
    MEI = 225 →
    Interpretation:
    If GF is 1 (100%) MEI generation will be 225 for each household member.
    If GF is 0.5 (50%) MEI generation will be 112.5 for each household member.