The option that most closely matches the actual difference in average global temperatures between 2023 and 2024, as reported by Nasa (gistemp), will be the winning bet. The market closes on December 31, 2024, and resolves when the annual global temperature data for 2024 is publicly available.
@WieDan Agree with Stephen. I would avoid satellite records. 3 most well established are NASA, NOAA and UK Hadley centre. Hadley has often taken longer to update so that suggests NASA or NOAA. Berkeley Earth is newer but has done some interesting new things.
For NASA it would be gistemp loti https://data.giss.nasa.gov/gistemp/tabledata_v4/GLB.Ts+dSST.txt is quite nice and easy to see.
NOAA is at https://www.ncei.noaa.gov/access/monitoring/monthly-report/global/202311
Berkeley Earth is at https://berkeley-earth-temperature.s3.us-west-1.amazonaws.com/Global/Land_and_Ocean_complete.txt
@ChristopherRandles @StevenK this is super helpful, thank you!!
Based on your message I think I would like to go with Nasa (gistemp) if this is fine by everyone.