The 10 Hottest Years on Record: A Climate Timeline

Every decade since 1980 has been warmer than the one before it, and the 10 hottest years in the 143-year instrumental record have all occurred since 2010. 2023 shattered the previous record by a remarkable 0.17 degrees Celsius, a margin scientists described as astonishing. The years 2016, 2020, and 2024 follow closely. The warming trend accelerated noticeably after 1990, with temperatures rising about 0.3 degrees per decade compared to 0.1 degrees per decade in the early 20th century.

El Nino events contribute to individual record years by temporarily transferring ocean heat to the atmosphere, but the underlying warming trend is entirely driven by greenhouse gas emissions. Annual global temperature now sits approximately 1.4 degrees Celsius above the 1850-1900 preindustrial baseline, approaching the 1.5 degree target of the Paris Agreement. Climate models project that without dramatic emissions cuts, global average temperature will exceed 2 degrees above preindustrial levels by the 2040s. The Arctic is warming 3-4 times faster than the global average, losing sea ice at a rate of about 13% per decade.

This amplification occurs because melting ice exposes darker ocean water that absorbs more sunlight, creating a positive feedback loop..