Crossing the Threshold: 98% Probability of 2°C Warming by 2100

The Paris Agreement aimed to limit global warming to "well below 2°C" above pre-industrial levels, with aspirations for 1.5°C. On Metaculus, where hundreds of forecasters have weighed in, the probability of at least 2°C warming by 2100 stands at 98%. The ambitious target is essentially treated as certain to be missed.

This isn't alarmism. It's probabilistic realism based on emissions trajectories and climate physics.

What 98% Means

A 98% probability leaves only 2% chance of staying below the Paris threshold. This would require:

• Immediate and dramatic emissions reductions
• Negative emissions technologies at scale
• Unexpectedly low climate sensitivity
• Some combination of fortunate developments

Forecasters see these scenarios as extremely unlikely given current trends. Emissions continue rising. Carbon capture remains nascent. Climate sensitivity estimates have narrowed around concerning values.

The 3.6°C Question

More alarming is the 20% probability of exceeding 3.6°C warming by 2100. This represents a world of:

• Massive coastal flooding from sea level rise
• Severe disruption to agriculture in many regions
• Extreme weather events far more frequent and intense
• Potential ecosystem collapse in vulnerable areas
• Significant human displacement and conflict potential

One in five odds of this scenario reflects meaningful possibility, not certainty—but it's high enough to warrant serious concern.

The Renewable Transition

Parallel markets offer modest optimism on energy transition:

• 95% odds that renewables contribute 25-48% of global electricity by 2030
• 85% odds that solar dominates renewable energy by 2031
• Just 1% odds that renewables fall below 25% by 2030

The energy transition is happening. It's just happening too slowly to prevent significant warming.

The CO2 Concentration Path

A market on atmospheric CO2 concentration gives just 8% odds that average levels stay below 423.89 PPM from 2024-2027. Current levels have already exceeded this in some readings. The trajectory is firmly upward.

This matters because CO2 concentration is what drives warming. Until emissions not only stop growing but actually turn negative, warming continues to accumulate.

What This Changes

The near-certainty of 2°C warming shifts the policy conversation:

From prevention to adaptation: Resources must increasingly flow toward preparing for climate impacts, not just preventing them.

From targets to triage: Which climate goals remain achievable? Which regions and populations are most vulnerable?

From optimism to realism: Climate policy based on scenarios that markets consider essentially impossible is not serious policy.

From global to local: International agreements that assume voluntary compliance have failed. Practical adaptation is often local.

The Fatalism Risk

There's a danger in these numbers: if 2°C is inevitable, why bother with mitigation? This would be a profound mistake:

• The difference between 2.1°C and 3.6°C is enormous
• Every tenth of a degree avoided prevents suffering
• Mitigation and adaptation are complementary, not alternatives
• Technology breakthroughs remain possible even if not probable

Conclusion

Prediction markets have rendered verdict on the Paris Agreement's 2°C target: it's almost certainly going to be missed. This isn't climate denial—it's climate realism. The question now is not whether we'll cross 2°C but how far beyond, and how we adapt to the changes that now appear inevitable. At 98% probability, planning for a warmer world isn't pessimism. It's prudence.

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Analysis informed by aggregated forecaster data from Metaculus as of January 20, 2026.