Global average surface temperature warming exceeds 1.5 degrees Celsius across a sustained multi-year average before 2030.
Public interest centers on when milestone climate impacts become locked in. Resolution relies on major climate monitoring bodies like NASA or Copernicus recording a multi-year mean anomaly above 1.5C over pre-industrial levels.
Across 6 frontier models answering independently, the panel thinks this is unlikely: the median is 31%.
They do not agree: GPT puts it at 63% and DeepSeek at 14%, 49 points apart. A spread that wide usually means the question turns on something none of them can see yet.
Nothing is settled until 17 Oct 2031, when the outcome is checked against sources and every number above gets a permanent score.
What each one said
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GPTOpenAI
It hinges on whether the recent 1.5°C annual overshoot persists through several more exceptionally warm years.
- WMO reported 2024 near 1.55°C above 1850–1900, but a single calendar year is not a sustained climate-average breach.
- NASA, Copernicus, WMO or HadCRUT must show a defined multi-year mean above 1.5°C by 2030; no universal window is specified.
- Five-year averages lag annual records, yet continued greenhouse-gas growth and ocean heat make a 2026–30 run of high anomalies plausible; a strong La Niña would cut odds.
63% -
GeminiGoogle
Turns on whether post-2023 surface warmth persists through upcoming ENSO cycles rather than reverting to the secular 0.2C/decade trend.
- WMO placed the odds of a 2024-2028 five-year average exceeding 1.5C at roughly 47%, driven by record 2023-2024 ocean heat uptake.
- A typical multi-year metric requires consecutive anomalous years, which moderate La Nina conditions in 2025-2027 could drag below 1.5C.
- If radiative forcing from shipping sulfur cuts and aerosol declines proves larger than IPCC mid-estimates, odds jump past 70%.
44% -
GrokxAI
Whether Copernicus/NASA 5-year GMST means first exceed 1.5 °C in a window ending 2029.
- 2024 annual already ~1.55 °C; current 5-yr mean ~1.42 °C and the observed 0.20–0.25 °C/decade trend puts 2025–29 near 1.48–1.52 °C.
- Bodies only need to publish the usual annual updates; no policy or emission threshold must be crossed first.
- IPCC AR6 20-yr crossing is ~2030–35, so a shorter window sits slightly above that median; a multi-year La Niña or aerosol rebound would drop it below 1.5.
42% -
ClaudeAnthropic
Hinges on whether 2026-2030 5-year running mean crosses 1.5C in major datasets like Copernicus/WMO.
- 2024 was first single year above 1.5C and 2023-2027 WMO forecasts put 20-year average near 1.3-1.4C, not yet a sustained multi-year 1.5C breach.
- Current multi-year averages (Copernicus, HadCRUT) sit around 1.2-1.3C, requiring a sharp further acceleration within just 4 years to cross 1.5C as a sustained mean.
- A major El Nino cluster or faster-than-expected forcing could push the 2026-2030 average near threshold, but most scientific projections see sustained 1.5C breach around…
20% -
QwenAlibaba
Requires a 5-year mean above 1.5°C by ~2029; current trend and inertia make that a stretch even with the 2023-24 step-change.
- The 2015-2024 decadal mean sits near 1.25°C; reaching 1.5°C on a 5-year window by 2029 needs ~0.25°C jump in under five years.
- WMO and IPCC AR6 projections place sustained 1.5°C crossing in the early-to-mid 2030s under SSP2-4.5, not before 2030.
- A persistent strong El Niño through 2027-28 or confirmation of a structural step-change (e.g., aerosol unmasking) would be the main upside surprise.
18% -
DeepSeekDeepSeek
Whether the 2024-2028 five-year window mean clears 1.5C, which hinges on La Niña timing and aerosol cuts.
- WMO's 2024-2028 outlook put the five-year mean at 1.1-1.9C, with roughly a 20% chance of exceeding 1.5C in at least one year, not the mean.
- A sustained multi-year average needs 2027-2029 to run hot; a strong La Niña in 2026-2027 would drag the mean below threshold.
- Current single-year anomalies near 1.45-1.55C mean the multi-year mean sits around 1.35-1.45C, so clearing 1.5C requires sustained record years.
14%
6 of 6 models answered · 49 points between the highest and lowest. None was shown the market price.
Question sourced from a news sweep on 18 Oct 2026. Forecast by google/gemini-3.8-flash, anthropic/claude-sonnet-5, openai/gpt-5.6-terra, x-ai/grok-4.6, deepseek/deepseek-v4.1-flash, qwen/qwen3.8-max-0902 via OpenRouter.