If the annual global mean surface temperature anomaly has reached or exceeded +2.0°C above pre-industrial levels (1850-1900 average) in any calendar year before Jan 1, 2050, then the market resolves to Yes. Sources from NCEI, Berkeley Earth, NASA Goddard Institute for Space Studies, and UK Met Office Hadley Centre (HadCRUT).

At least two of the Source Agencies must report that we have hit the 2.0°C threshold.