Natural Climate Solutions MACC Explorer

Annual Budget

Total budget $50M / yr

Allocation Across Pathways

Afforestation25%

Mangrove restoration25%

Soil carbon farming25%

Avoided deforestation25%

Portfolio Result

CO₂ sequestered / yr

0 Mt

Land committed

0 kha

Blended cost

$0 / tCO₂

How it works

Each natural climate solution (NCS) pathway has a rising marginal cost: the best, cheapest land (degraded pasture, existing mangrove fringe) gets restored first, and every extra hectare costs more as good sites run out. For pathway i with budget share B_i, area restored follows a saturating cost curve:

A_i(B_i) = A_max,i · (1 − e^(−B_i / k_i))
CO2_i  = A_i(B_i) · 1000 · r_i        (tonnes CO2/yr)
MC_i   = dB_i/dCO2_i  = 1e6 / (dCO2_i/dB_i)   ($ per tonne, the slope of the cost curve)

Instead of a 3D landscape, this version plots the same equations directly: the top chart is a marginal abatement cost curve (MACC) — the classic 2D chart economists and the IPCC use for exactly this problem. Each pathway is a bar whose width is tonnes of CO₂ abated per year and whose height is its current marginal $/tonne, sorted cheapest-first left to right — the bars trace out the same diminishing-returns economics as the 3D landscape's growth, without a camera. Below it, four small curves show each pathway's own A_i(B_i) saturation curve with a dot marking today's allocation.

Afforestation — ≈6 tCO₂/ha/yr, huge available area, moderate cost.
Mangrove restoration — ≈15 tCO₂/ha/yr ("blue carbon"), small available area, high cost per hectare.
Soil carbon farming — ≈1.2 tCO₂/ha/yr, very large area, cheapest per hectare but low density.
Avoided deforestation — ≈9 tCO₂/ha/yr emissions prevented, moderate area, mid cost.

Move the sliders to split the budget; because each curve saturates, dumping 100% into one pathway buys far fewer tonnes per dollar than spreading budget across all four. "Cheapest-first" greedily allocates budget to whichever pathway currently has the lowest marginal $/tonne, which is exactly what pulls the MACC curve as flat and low as possible for a given budget.

Afforestation Mangrove restoration Soil carbon farming Avoided deforestation