I am still building Therma, a climate and human-migration simulator that runs from 1784 to 2040, connecting atmospheric carbon dioxide, ocean heat, temperature, humidity, infrastructure pressure, water costs, and family history across more than two centuries. The year 1784 is not arbitrary: it is the birth year of the earliest person currently represented in my family tree, Thomas Cleophas Hamilton, born in Lincoln County, North Carolina, and it falls near the end of the period when atmospheric CO₂ remained close to its long-term natural baseline of roughly 280 ppm. Therma begins at 280.4 ppm in 1784, then follows both the changing planet and the movement of my ancestors from places including Ireland, England, the German states, and the Russian Empire into the United States and eventually toward San Diego. By 1920, planetary CO₂ reaches 304.9 ppm; by 1972, it reaches 337.6 ppm. In 1991, Therma displays a surface temperature anomaly of +0.13°C, an ocean surface anomaly of +0.11°C, a regional wet-bulb temperature of 16.7°C, grid overhead of +4%, a water-cost index of -83, and atmospheric CO₂ of 369.1 ppm. By 2025, those simulated indicators have shifted substantially: the surface anomaly reaches +0.85°C, the sea-surface temperature anomaly reaches +0.74°C, regional wet-bulb temperature rises to 18.1°C, grid overhead climbs to +29%, the water-cost index reaches 44, and the most recent recorded CO₂ anchor used by the simulator is 423.9 ppm. Placing 1991 and 2025 side by side turns abstract climate measurements into a systems story: warmer air changes human heat exposure, warmer oceans store enormous amounts of accumulated energy, electrical systems spend more capacity coping with cooling demand and peak loads, and water becomes increasingly expensive to capture, move, treat, and deliver. Therma is designed to show those relationships on the same timeline as ordinary human lives—births, migrations, families, deaths, and the movement of generations across continents and states.
One of the central ideas behind Therma is that the ocean behaves like a planetary heat sponge. More than 90 percent of the excess heat accumulated in Earth’s climate system is stored in the ocean, which is why the simulator tracks sea-surface temperature separately from atmospheric surface temperature and allows ocean conditions to respond more slowly. Therma currently treats 1981 as its internal equilibrium baseline, with surface temperature, ocean temperature, wet-bulb conditions, electrical-grid overhead, and water costs responding differently as the climate moves away from that reference point. Recent observations make that long-memory behavior especially important: the World Meteorological Organization’s State of the Global Climate 2025 reports record ocean heat content and notes that the rate of ocean warming during 2005–2025 was more than twice the rate observed during 1960–2005, while NOAA climate records provide another instrumental view of the continuing accumulation of heat in the Earth system. That means an individual year can be cooler than the year before without reversing the underlying trend—the stored energy does not simply disappear when atmospheric temperatures temporarily fluctuate. Therma is still a work in progress, and my next steps are to calibrate population cohorts against real San Diego demographic data, add survival outcomes that give changing environmental conditions clearer demographic consequences, build a family memory log so descendants visibly carry the history of earlier generations through the simulation, and continue identifying additional planetary variables worth modeling between 1784 and 2040. The goal is to make climate change something that can be walked through year by year: not merely a graph of atmospheric CO₂ or global temperature, but a living timeline showing what the planet was like when a person was born, where that person traveled, what environmental conditions surrounded their life, and what kind of world their descendants inherited.
Sources: World Meteorological Organization, State of the Global Climate 2025: https://wmo.int/publication-series/state-of-global-climate/state-of-global-climate-2025 · NOAA National Centers for Environmental Information, Global Climate Report — 2025: https://www.ncei.noaa.gov/news/global-climate-202513
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