Trajectory

Where we are, where the climate is heading under different choices, and what experts think about the largest risks. The three kinds of statement are always marked: OBSERVED measurements, PROJECTION scenarios that depend on choices, EXPERT ESTIMATE personal judgements.

Where we are

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The WMO puts long-term warming at 1.34–1.41 °C above 1850-1900 and found 2024 alone about 1.55 ± 0.13 °C. WMO report ↗

Where it could go: IPCC scenarios

PROJECTION Warming by 2081-2100 vs 1850-1900 (best estimate and very likely range)

SSP1-1.9very low emissions1.4 °C (1–1.8)
SSP1-2.6low1.8 °C (1.3–2.4)
SSP2-4.5intermediate2.7 °C (2.1–3.5)
SSP3-7.0high3.6 °C (2.8–4.6)
SSP5-8.5very high4.4 °C (3.3–5.7)

PROJECTION Global sea level rise by 2100 vs 1995-2014 (median and likely range)

SSP1-1.9very low emissions0.38 m (0.28–0.55)
SSP1-2.6low0.44 m (0.32–0.62)
SSP2-4.5intermediate0.56 m (0.44–0.76)
SSP3-7.0high0.68 m (0.55–0.9)
SSP5-8.5very high0.77 m (0.63–1.01)

These are scenarios of what follows from different emission paths, not predictions: the path is a human choice. Sea-level rise would continue for centuries beyond 2100, and the high end is uncertain because of ice-sheet behaviour. IPCC AR6 WGI SPM ↗. Tipping points are on the climate tipping scenario.

What experts estimate about the largest risks

EXPERT ESTIMATE Toby Ord, The Precipice (2020): chance of an existential catastrophe within the next 100 years

Asteroid or comet impact1 in 1,000,000
Supervolcanic eruption1 in 10,000
Stellar explosion1 in 1,000,000,000
Total natural risk1 in 10,000
Nuclear war1 in 1,000
Climate change1 in 1,000
Other environmental damage1 in 1,000
Naturally arising pandemics1 in 10,000
Engineered pandemics1 in 30
Unaligned artificial intelligence1 in 10
Unforeseen anthropogenic risks1 in 30
Other anthropogenic risks1 in 50
Total anthropogenic risk1 in 6
Total existential risk1 in 6

Bars use a logarithmic scale from 1 in a billion to 1 in 1.

Other expert estimates, side by side

EXPERT ESTIMATE Advanced AI: in a survey of 2,778 AI researchers, between 38% and 51% (depending on the question) gave at least a 10% chance to outcomes as bad as human extinction, while Ord puts unaligned AI at 1 in 10 for the century. Other experts rate it far lower. Grace et al. 2024 ↗
EXPERT ESTIMATE Carrington-class solar storm: about 12% per decade in Riley's 2012 power-law estimate; later about 10%; other methods range from about 1.5% to 85%. Riley 2012 ↗
PROJECTION Cascadia magnitude ~9 earthquake: 10–15% in the next 50 years (USGS 2025). USGS ↗

These are personal judgements by experts, built from limited evidence and not comparable to measurements. They differ by orders of magnitude between authors and methods, which is itself the finding. This site never adds probabilities of its own. See the scenarios for the reasoning behind each, and how the labels work.