Three things we can change. Three we can't.
Climate-tipping science has been hampered by a single technical problem: model ensembles produce wide tipping-threshold ranges (AMOC: 1.4–8°C; Amazon: 2–6°C) because the models disagree. The framework's contribution is a unified diagnostic that tells you, observable by observable, which signals are robust across models — and therefore which mitigation choices actually matter.
Climate Mitigation Atlas — \(\beta\) by observable × emissions pathway
Each cell's colour is one number — the rate exponent \(\beta\). Green = stoppable (returns to rest). Orange = super-rate. Red = locked-in.
Click any cell for the full reading: \(\beta\), cross-model dispersion, theorem anchor, and the source code on GitHub.
How to read this chart · what the SSPs mean
The axes
- Rows: 8 climate observables — what is changing.
- Columns: 5 emissions pathways from "very aggressive mitigation" (left) to "no mitigation" (right).
- Cell colour: the rate exponent \(\beta\). Below 1 is stoppable; above 1 is locked-in.
- Cell label: the actual \(\beta\) value cross-model median.
The five emissions pathways (SSPs)
- SSP1-1.9 — ~1.5°C. Aggressive net-zero by mid-century. Paris lower bound.
- SSP1-2.6 — ~2°C. Moderate mitigation. Net-zero by ~2070.
- SSP2-4.5 — ~2.7°C. Current policies, middle-of-the-road.
- SSP3-7.0 — ~3.6°C. Regional rivalry, fragmented action.
- SSP5-8.5 — ~5°C. Continued fossil-fuel growth, no mitigation.
SSPs (Shared Socioeconomic Pathways) are the IPCC's standard set of emissions futures. The number after the dash is the radiative forcing in 2100 (W/m²).
What we can change
Stoppable
CO₂ growth itself
Under SSP1-2.6 the framework reads atmospheric CO₂ as deeply sub-rate post-2024 (β = −24.3). Under SSP5-8.5 it crosses β = 1 forward in 2038. Mitigation works on the trajectory.
Stoppable
Aggregate sea-level rise
SSP1-1.9 wins the framework's three-criterion best-pathway test (rank-sum 7 of 24): tightest cross-model agreement, smallest mean rate, β farthest below 1.
Stoppable
Glacier decline rate
Glaciers stay sub-rate everywhere, but the rate scales with forcing (β = 0.21 SSP1-1.9 → 0.90 SSP5-8.5). Mitigation buys you decades of glacial retention.
What we can't
Locked in
Antarctic ice-sheet collapse
β = 3.21 to 3.76 across every SSP including SSP1-1.9. AIS dominates sea-level rise post-tipping; aggregate GMSL projections hide the component lock-in.
Already crossed
Permafrost first regime change
The framework identified +0.36 ± 0.12 K as the first permafrost change-point. Earth is at +1.2 K. The threshold is in the past tense. Mitigation now reduces post-tipping rate, not whether the tip has happened.
Locked in
Greenland ice-sheet acceleration
β = 1.18 to 1.51 across all SSPs. Less dramatic than Antarctica, but the same conclusion: super-rate under every emissions pathway. Mitigation reduces magnitude, not regime.
What's uncertain — and why the answer surprised us
Counter-intuitive
Aggressive mitigation widens, not narrows, the uncertainty band on sea-ice and AMOC
Under SSP1-1.9, model disagreement on Arctic sea-ice (σ_cross = 5.10) is 7× wider than under SSP5-8.5 (σ_cross = 0.69). The forcing signal disappears beneath internal variability. The same effect appears for the AMOC.
Standard ensemble-mean climate projections do not surface this — they take per-SSP means and don't measure cross-model dispersion per SSP. Aggressive policy assessments need wider uncertainty bands, not narrower.
Two more findings worth your attention
Aggregate hides truth — focus on components
Sea-level rise projections look reassuring under SSP1-1.9 (aggregate β = -1.12, sub-rate). The dominant component — Antarctica — is super-rate (β = +3.76) under the same SSP. The framework's component decomposition reveals where mitigation actually matters: the Antarctic-specific feedback loops (basal melt, marine ice cliff instability) drive the post-tipping rate, not aggregate emissions.
Montreal worked. The original intervention was the lever.
Counterfactual analysis: without the 1987 Montreal Protocol, the framework reads Antarctic ozone hitting zero by 2010. Strengthening compliance further produces only marginal recovery acceleration. The original act of intervening was the principal lever, not subsequent tightening. A useful template for what successful intervention looks like in framework-native terms.
Read deeper
- Best pathways — per-observable best SSP with the framework's reasoning.
- Locked-in risks — Antarctica, Greenland, permafrost.
- Mitigation-sensitive cascades — CO₂, sea-level, glaciers, steric expansion.
- The σ_cross paradox — why aggressive mitigation widens sea-ice/AMOC uncertainty.
- Component decomposition — Antarctica as the dominant sea-level rise driver.
- Honest scope — what the framework cannot prescribe.