This prediction market asks whether 2026 will be the hottest year ever recorded, using a specific metric: the unsmoothed Land-Ocean Temperature Index (LOTI) from NASA’s Goddard Institute for Space Studies (GISS). The market resolves to “Yes” if the 2026 LOTI value exceeds both the 2025 value and 1.28 degrees Celsius. The LOTI measures global average surface temperature anomalies relative to a 1951-1980 baseline. NASA GISS is one of the primary global temperature records, alongside those from NOAA and the UK Met Office. The 1.28°C threshold is significant because it represents a level that has not been consistently reached before, though 2023 and 2024 have seen record-breaking anomalies. If 2026 surpasses this value, it would mark a new high in the instrumental temperature record, which dates back to 1880. Interest in this question is driven by accelerating climate change and the recent string of record-breaking years. 2023 was the hottest year on record, with a GISS LOTI anomaly of approximately 1.17°C. 2024 is virtually certain to beat that, with early data showing anomalies above 1.3°C. The question of whether 2026 will continue this trend depends on multiple factors: the state of the El Niño-Southern Oscillation (ENSO), which can temporarily boost global temperatures; the continued rise in greenhouse gas concentrations; and natural variability. The market will close at the end of 2026, and the final resolution will depend on the official NASA GISS data release, typically in early 2027. This topic matters because a new hottest year would signal that the planet is warming faster than expected, with consequences for extreme weather, sea-level rise, and ecosystem disruption. It also tests the reliability of climate models and the effectiveness of international climate policies. For scientists, policymakers, and the public, the outcome provides a clear, data-driven benchmark for the state of the climate system. Readers should understand that this is not a simple bet on a single temperature number. The resolution criteria involve both a comparison to the previous year and an absolute threshold. The market’s design reflects the reality that global temperature records are now being broken with increasing frequency, and that even a slight cooling year (e.g., due to a La Niña event) could still result in a record if the underlying warming trend is strong enough. The market will be resolved after the official NASA GISS data is published, which typically happens in January or February of the following year.

Historical Context

The instrumental global temperature record maintained by NASA GISS dates back to 1880. For much of the 20th century, global temperatures fluctuated but remained within a relatively narrow range. The warmest year on record prior to the 21st century was 1998, which saw a strong El Niño event and a GISS LOTI anomaly of about 0.63°C. The 2000s saw a series of new records: 2005, 2010, 2014, 2015, 2016, 2019, 2020, and 2023 all set or tied records. 2016 was the previous record holder with an anomaly of about 1.00°C, driven by a very strong El Niño. 2023 broke that record by a wide margin, reaching approximately 1.17°C, and 2024 is on track to exceed 1.3°C. The trend is clear: the rate of warming has accelerated. The 2010s were about 0.2°C warmer than the 2000s, and the 2020s are already warmer than the 2010s. The last time a year was cooler than the previous record was 2016, and that record stood for seven years until 2023. The frequency of record-breaking years is increasing. The 1.28°C threshold specified in this market is not an arbitrary number; it is roughly in line with the current trajectory of global warming. If 2026 exceeds this value, it would mean that the planet has warmed by more than 1.3°C above pre-industrial levels, a level that the Paris Agreement aims to limit to 1.5°C over the long term. Past predictions of record temperatures have often been accurate. For example, in early 2023, scientists predicted that 2023 or 2024 would likely be a record year due to the developing El Niño. That prediction was correct. The question for 2026 depends on whether the ENSO cycle will be in a warm phase and whether the underlying warming trend will continue. The 2023-2024 El Niño was strong but not exceptional. If a La Niña develops in late 2024 or 2025, it could temporarily suppress global temperatures, making a 2026 record less likely. However, if a new El Niño develops in 2026, the combination of background warming and El Niño could easily push temperatures above 1.28°C.