Spaghetti Scenarios · Global risk

Climate change

Earth is warming because of the gases we release when we burn fossil fuels. The line starts at today's warming and follows where it would go depending on what humanity does. Move it and see when it crosses the +1.5 °C threshold, how far it moves past it, and which Semiversal state it lands in. A line is a direction, not a date.

1.37 °CHuman-caused warming (2025)

~2030projected crossing of +1.5 °C

View from

Warming trajectory

Show uncertainty

Year: 2050

Crossing +1.5 °C

Sustained human-caused warming above +1.5 °C, measured as a twenty-year average

Impact

Major (4)

Probability

Almost certain (5)

Timeframe

Crossing projected around ~2030

Score

Confidence

High

Reversibility

Partially reversible or persistent

Signals

Annual and decadal temperature anomaly
Remaining carbon budget: ~170 GtCO₂ from early 2026 (Global Carbon Budget 2025)
Sea ice extent
State of the AMOC
Coral bleaching
Sea level

Tipping points

Irreversible triggering of one or more tipping points: Greenland, West Antarctica, the AMOC or the Amazon

Impact

Catastrophic (5)

Probability

Uncertain

Timeframe

Undetermined; the risk grows with every tenth of a degree

Score

N/A

Confidence

Medium for the mechanism; low for the probability

Reversibility

Irreversible on a human timescale

Signals

State of the AMOC
Mass balance of Greenland and West Antarctica
Amazon die-off

Effective mitigation

The bright side of the same scenario: the higher-action pathways are the ones that would make it happen.

Probability: Uncertain
Confidence: Medium

The matrix, as in the Excel file

Change impact and probability to see where the scenario lands. Up above, the physics moves; here, the rating moves.

Impact ↓ · Probability →RemoteUnlikelyPossibleVery likelyAlmost certainCatastrophicMajorModerateMinorNegligible

ImpactProbability

I × P score (baseline)20

Weighted risk R% (Excel)72%

Certainty 81%–100%. The Excel file uses the midpoint 90%; baseline v0.9.1 (sec. 6.2) dropped midpoints, so R% is shown for comparison only.

Matriz de escenarios.xlsx (sheet 'Valuación y ponderación', i.e. valuation and weighting): R% = midpoint P × I / 5. Baseline v0.9.1 sec. 6.2 dropped the use of midpoints; the official score is I × P (1–25).