EARTHTRACKER
Sector 03 · Self-learning energy-balance ensemble

Projections

A two-layer energy balance model, run as thousands of parameter sets and continuously re-weighted against the observed record. Each time new data arrives the ensemble evolves into a new generation, and every generation's projections are logged permanently.

GEN-—

Global temperature · projected to 2100

Shading: 5–95 % (light) and 17–83 % (dark) ranges, including parameter uncertainty and year-to-year internal variability. °C relative to 1850–1900.

Climate sensitivity

Transient response

Aerosol forcing 2019

Evolution · ECS by generation

Live generations only · band = 5–95 %

Generation log

Select a row to load that generation

Scenario guide · what each projection means

All five projections use the same model, the same physics and the same calibrated ensemble. The only thing that changes is the assumed future: how much CO₂, methane, nitrous oxide and air pollution the atmosphere will contain between the data cutoff and 2100. The differences between the curves therefore show the effect of human choices, not of model uncertainty.

SSP3-7.0
SSP
Shared Socioeconomic Pathway, the scenario framework used by the IPCC.
3
Storyline family 1–5: how the world develops (population, economy, cooperation, energy).
7.0
Nominal radiative forcing reached in 2100, in W m⁻². Higher means more heat trapped.

Side by side · inputs and results

The nominal forcing is the target the scenario was designed for. The model forcing is what EarthTracker computes from the concentrations with the selected equations (IPCC AR6 ERF by default), scaled by each ensemble member's learned forcing factors, so the two differ somewhat.

How every projection is built

  1. Measure. NASA GISTEMP and NOAA GlobalTemp temperatures, plus NOAA greenhouse-gas records, up to the generation's data cutoff.
  2. Convert to forcing. Concentrations become radiative forcing (W m⁻²) using the IPCC AR6 or NOAA AGGI equations, plus aerosols, ozone, volcanoes and the solar cycle.
  3. Learn. Thousands of versions of a two-layer energy balance model (different climate sensitivity, ocean heat uptake and aerosol strength) are run from 1750 and weighted by how well they reproduce the observed temperature record. Each generation starts its search from the previous one.
  4. Extend the future. From the cutoff year, each scenario supplies its own path for the gases and aerosols. That path is the only difference between the curves.
  5. Project with uncertainty. Every surviving ensemble member is run to 2100 under each scenario, with realistic year-to-year natural variability (El Niño / La Niña) added. The line is the median; the bands are the 17–83 % and 5–95 % ranges. No future volcanic eruptions are assumed.
  6. Log it. The projections are saved permanently, so the Deviation page can later compare them with what actually happened.

Full equations and references: Methods · Forcing.