How Is Social Cost of Carbon Calculated? Interactive Calculator
The social cost of carbon, or SCC, is the estimated dollar value of worldwide damages caused by emitting one additional metric ton of carbon dioxide in a given year. This interactive calculator lets you estimate those damages for a chosen amount of emissions, compare discount rate scenarios, and see how the result changes over time.
Expert Guide: How the Social Cost of Carbon Is Calculated
The social cost of carbon is one of the most important concepts in climate economics because it translates physical emissions into an estimated monetary damage. In plain language, it asks a practical question: if one extra metric ton of carbon dioxide enters the atmosphere today, what is the present value of the harm it creates over time? Those harms can include lower agricultural productivity, worse human health outcomes, property damage from flood risk, energy system impacts, ecosystem losses, and other climate related economic effects. Policymakers use this number to evaluate regulations, investment decisions, and the benefits of reducing emissions.
A simple way to think about the calculation is this: economists estimate how an added ton of CO2 changes atmospheric concentrations, how those concentration changes affect temperature and climate systems, how those climate changes affect economies and welfare, and then discount future damages back into present day dollars. That sounds straightforward, but each stage requires modeling and assumptions. The final estimate depends heavily on climate sensitivity, damage functions, socioeconomic pathways, and the discount rate applied to future costs.
The Basic Steps in an SCC Calculation
- Specify the pulse emission. Analysts begin with one extra metric ton of CO2 emitted in a particular year, such as 2025.
- Model the carbon cycle. Integrated assessment models estimate how much of that ton remains in the atmosphere over time versus being absorbed by land and oceans.
- Estimate temperature response. The model translates increased atmospheric concentration into changes in radiative forcing and global temperature.
- Apply damage functions. Economists estimate how higher temperatures affect output, health, agriculture, labor productivity, coastal assets, and other sectors.
- Discount future damages. Because many damages occur decades in the future, analysts convert them to present value using one or more discount rates.
- Average across scenarios and uncertainty. The final SCC is often derived from many model runs with different economic growth paths, climate responses, and impact assumptions.
Why Discount Rates Matter So Much
The discount rate is often the single most visible driver of the published SCC value. A lower discount rate places more weight on future climate damages, which raises the present value of an extra ton of CO2. A higher discount rate does the opposite. This is why SCC estimates can differ substantially between a 2.5% and 5% discount rate, even when the underlying climate science is similar.
If future damages are expected to persist for centuries, discounting becomes especially important. Climate change is a long lived problem because carbon dioxide remains in the climate system for a very long time and because some damages, such as sea level rise, unfold gradually. A lower rate captures the idea that future generations should count more heavily in present day policy analysis. A higher rate reflects a stronger preference for present consumption over future consumption. In practice, agencies often show a range of discount rates rather than a single figure.
Integrated Assessment Models Used in SCC Work
Historically, government SCC estimates have relied on integrated assessment models, often called IAMs. These models combine climate science and economics in a single framework. Well known examples include DICE, FUND, and PAGE. Each model approaches uncertainty and damages somewhat differently, which is one reason why analysts usually examine distributions and ranges rather than claiming exact precision.
IAMs are useful because they connect several systems that otherwise would be studied separately. A climate model alone might tell you about warming. An economic model alone might tell you about growth. The SCC requires linking the two, then tracing a small pulse of emissions through time. That linkage is what allows a regulator or business analyst to estimate the benefits of reducing one ton, one thousand tons, or one million tons of CO2.
Main Inputs That Shape the Final Estimate
- Emission year: the SCC usually rises over time because societies are expected to be exposed to greater climate damages at higher temperatures.
- Socioeconomic pathway: future population and income growth affect both emissions and vulnerability.
- Climate sensitivity: higher temperature response to greenhouse gases raises projected damages.
- Damage functions: these translate physical climate effects into economic losses.
- Discount rate: this determines the present value assigned to long run impacts.
- Treatment of uncertainty: tail risks and catastrophic possibilities can materially raise SCC estimates.
Simple Calculator Logic Versus Full Government Methodology
A public facing calculator like the one above uses a simplified but useful formula:
Total climate damages = CO2 emissions × SCC value per metric ton.
That approach is appropriate when you already have an SCC schedule by year and discount rate. It is not a full recreation of the government modeling pipeline, but it mirrors how analysts often apply SCC values in cost benefit analysis. For example, if the SCC in 2025 is estimated at $120 per metric ton under a given discount rate, then 1,000 metric tons of CO2 would imply roughly $120,000 in monetized global damages.
The calculator on this page uses year specific SCC estimates that rise over time and allows you to compare discount rate assumptions. This is exactly how SCC is often operationalized in policy analysis: estimate the quantity of emissions, select the relevant SCC for the year, and monetize the resulting damages or avoided damages.
Comparison Table: Example SCC Values by Discount Rate and Year
| Emission Year | 2.5% Discount Rate | 3.0% Discount Rate | 5.0% Discount Rate |
|---|---|---|---|
| 2020 | $116 per metric ton CO2 | $86 per metric ton CO2 | $18 per metric ton CO2 |
| 2025 | $120 per metric ton CO2 | $90 per metric ton CO2 | $20 per metric ton CO2 |
| 2030 | $139 per metric ton CO2 | $103 per metric ton CO2 | $25 per metric ton CO2 |
| 2040 | $168 per metric ton CO2 | $126 per metric ton CO2 | $34 per metric ton CO2 |
| 2050 | $205 per metric ton CO2 | $155 per metric ton CO2 | $45 per metric ton CO2 |
What Damages Are Included in the Social Cost of Carbon?
The SCC is broad because climate change affects many parts of the economy. Most damage estimates try to capture market and nonmarket consequences, though some impacts remain hard to monetize. Typical categories include:
- Changes in agricultural output from heat stress, precipitation changes, and extreme weather
- Human health impacts such as heat mortality and disease burdens
- Coastal damages from sea level rise and storm surge
- Energy demand changes, including higher cooling needs
- Labor productivity losses due to extreme heat
- Ecosystem and biodiversity impacts, though these are often undercounted
- Potential conflict, migration, and macroeconomic disruptions that are difficult to estimate precisely
Because some categories are difficult to value, many experts argue that published SCC values may still understate the full social damages of emissions. For example, tipping points, irreversible ecosystem changes, and distributional impacts across vulnerable populations are often incompletely represented in older integrated assessment models.
Comparison Table: Why One Ton Matters at Scale
| CO2 Quantity | Illustrative SCC at $90 per ton | Illustrative SCC at $155 per ton |
|---|---|---|
| 1 metric ton | $90 in damages | $155 in damages |
| 1,000 metric tons | $90,000 in damages | $155,000 in damages |
| 100,000 metric tons | $9,000,000 in damages | $15,500,000 in damages |
| 1,000,000 metric tons | $90,000,000 in damages | $155,000,000 in damages |
How Governments Use the SCC in Policy Analysis
In regulatory impact analysis, agencies compare the benefits and costs of proposed rules. If a regulation reduces carbon emissions, the avoided tons are multiplied by the SCC for each year in which those reductions occur. The result is a monetized climate benefit. That value can then be added to other benefits, such as improved air quality or lower fuel use, and compared against compliance costs.
This is why SCC is so influential in energy efficiency standards, vehicle rules, power sector regulations, methane programs, and infrastructure planning. It allows climate impacts to be analyzed in the same dollar framework used for other policy costs and benefits. Without an SCC, many climate benefits would be omitted from formal economic analysis.
Limitations and Ongoing Debates
Although the SCC is essential, it is not a perfect number. There are active debates about whether traditional IAMs capture catastrophic risks, whether damages rise nonlinearly at high temperatures, how to represent equity across countries, and whether discounting should decline over long time horizons. Another debate concerns the geographic scope of damages. Many economists support a global SCC because greenhouse gases mix globally and emissions in one country affect people everywhere. Others focus on domestic damages for some legal or policy purposes.
There is also a major methodological shift toward richer climate damage datasets, more transparent uncertainty analysis, and improved treatment of persistent impacts. As models improve, published SCC values have tended to rise, not because the basic idea changed, but because new evidence suggests climate damages are larger and more persistent than some older models assumed.
How to Interpret the Calculator on This Page
Use this calculator as a policy and planning tool, not as a substitute for a full peer reviewed regulatory analysis. It is best for translating a known amount of CO2 emissions into an estimate of climate damages under selected discount rate assumptions. For businesses, that can support internal carbon pricing, project appraisal, transition planning, and scenario analysis. For students and researchers, it offers a transparent way to understand how much the chosen discount rate changes the result.
The calculation is simple by design. You enter emissions in metric tons, choose the emission year, select the discount rate scenario, and the tool multiplies your emissions by the SCC estimate for that year and rate. The chart then compares the same emissions amount across discount rates so you can see how sensitive the result is to discounting assumptions.
Authoritative Sources for Further Reading
- U.S. Environmental Protection Agency: Social Cost of Carbon
- The White House: Technical Support Document for Social Cost of Greenhouse Gases
- University of Chicago explainer on the social cost of carbon
Bottom Line
The social cost of carbon is calculated by estimating the incremental future damages caused by one additional metric ton of CO2 and discounting those damages into present value dollars. At a practical level, once the SCC schedule is established for each year and discount rate, the monetized damage from emissions is calculated by multiplying tons of CO2 by the relevant dollar per ton estimate. That is the logic this calculator uses. The sophistication lies behind the scenes in the climate and economic modeling, but the application is intentionally simple: more emissions imply larger expected social damages, and lower discount rates imply higher present value estimates of those damages.