lifetimestrillions

lifetimestrillions is a proposed unit of measure used in long-term planning and risk assessment to quantify the cumulative lifetime potential of a population or system, expressed in trillions of person-years. It aggregates the lifespans of individuals over a defined period, providing a single scalar that can be compared across scenarios.

Origin of the term appears in discussions of long-term impact assessment from the 2020s onward, where researchers sought a compact way to convey large-scale intergenerational potential in policy debates and simulations.

Definition and calculation: lifetimestrillions equals the sum of the lifetimes of all individuals within the analysis window, typically measured as years lived, divided by 1e12. For example, a country with 60 million births in a year and an average life expectancy of 80 years would contribute about 4.8e9 person-years per birth cohort, or roughly 0.0048 lifetimestrillions. Across an entire population and multiple cohorts, values can accumulate to several lifetimestrillions.

Applications: proponents use lifetimestrillions to evaluate long-term policy impact, including investments in health care, education, climate resilience, population planning, and governance of advanced technologies. The metric aims to provide a common scale for comparing scenarios with very different demographic structures or time horizons.

Limitations: as a high-level aggregate, lifetimestrillions can obscure distributional details, quality of life, and inequalities. Data quality, modeling assumptions, and ethical considerations can affect comparability and interpretation.

See also: life expectancy, person-years, cohort analysis, intergenerational ethics.