InVEST Tier 1 Carbon Model

In the Tier 1 model we estimate carbon stock as a function of land use / land cover. Storage indicates the mass of carbon in an ecosystem at any given point in time. Sequestration indicates the change in carbon storage in an ecosystem over time. Valuation is applied to sequestration Carbon Storage and Sequestration

Tier 1 Carbon Storage Model Atmosphere Soil type, moisture Microbes, chemistry Species Harvested Wood Products Aboveground biomass Belowground biomass Dead wood Atmosphere Land management Land use history Decay Soil carbon Climate

Tier 1 Carbon Storage Model Atmosphere Soil type, moisture Microbes, chemistry Species Harvested Wood Products Aboveground biomass Belowground biomass Dead wood Atmosphere Land management Land use history Soil carbon Decay 5 pools x f(cost/ton) = Value Climate

Sequestration and Value 2008 Future Value Net Present Value Δ in C 2058

Net Present Value is a function of: Market discount rate Rate of change in the social value of carbon Social or market cost of carbon Carbon model is most appropriate for valuing the Social cost of carbon : The price of current and future damage caused by releasing a ton of carbon into the atmosphere Approach to Valuation

Input Data Required data: A land use / land cover (LULC) map Table of carbon pools (metric tons / hectare)

Optional data: For calcuating C stored in harvested wood produtcs: – Map of timber harvest land parcels with data on – frequency of harvest – annual harvest amount – decay rate of wood products – density / volume factors Future land use map Economic data (carbon value / price, discount rate) Input Data

Local plot studies Published analyses on similar regions IPCC tables Carbon Pool Data

Map of current carbon storage (Mg/cell) Map of future carbon storage - If future land use provided Carbon sequestration map = (future - present carbon storage) Map of economic value of carbon sequestered Output

Simple, requires relatively little data, thus also works for data-sparse regions Both biophysical (carbon storage / sequestration) and economic valuation modeling possible Strengths

Output is only as detailed and reliable as the land use classes and carbon pool data that are input. Carbon sequestration does not occur in an area unless the area’s land use changes over time or wood is harvested. Limitations Simplified carbon cycle Economic valuation assumes a linear trend in sequestration over time

Land cover transitions T2 Storage in Biomass Reality Model T1 Forest (young) Forest (old) T2 T1 Forest

Land use planners: Compare consequences of future scenarios Ecosystem service tradeoffs Carbon market: First-pass analysis Not appropriate for precise cost- benefit analysis etc Application

Gains and losses in carbon stocks from 2008 to 2058 in Sumatra, Indonesia 2008 Vision Plan Carbon gain Carbon loss 2058

Dharmasraya district, Sumatra, Indonesia Carbon gains and losses under alternative scenarios Loss Gain 2008 to Green Vision 2008 to Business as Usual Plan

Priority districts for investing in forest carbon projects High priority districts have: -High deforestation risk - Large biomass carbon stocks - Relatively lower agricultural value