(703g) Carbon Calculus™: New Metrics for Sustainable Decision-Making

According to the World Meteorological Organization (WMO), the past ten years 2015-2024 were the ten warmest years on record. Driven by the greenhouse effect, emitted greenhouse gases (GHGs) cause an energy imbalance measured by radiative forcing and realized as global average temperature increases. In 2023, the Annual Greenhouse Gas Index was 1.51, representing a 51% increase in radiative forcing since calendar year 1990: a 9% increase from methane, nitrous oxide, and other GHGs, and a 42% increase caused by carbon dioxide (CO2) emissions alone.

If you were asked to allocate resources to fund a variety of CO2 reduction projects over the next 20 years, how would you approach this decision? Solar energy, electric vehicles, planting trees, direct air capture, procuring low-carbon materials—all of these decarbonization projects are important. However, if your funding is limited, how do you decide which actions to take, when to take them, and in what order?

Derived from carbon-climate impulse response models, Carbon Calculus™ is a novel decarbonization decision-making tool that integrates the time value of CO2 into a simple CO2 sink dissipation model. New metrics are defined, including Net Present Value of CO2 (NPVCO2), which quantitatively values and compares decarbonization strategies across different magnitudes and time frames. The form of this resulting model has additional social potential to bridge the gap between climate science and decarbonization investment decisions. Results quantitatively support the importance of early decarbonization action.