[OC] 146 Years of Global Warming: Every year’s temperature since 1880, colored by anomaly. 2025, 2024, and 2023 are the three warmest years in NASA’s entire record.

Source & Methodology

• Data: NASA GISTEMP v4 — downloaded directly from data.giss.nasa.gov/gistemp on 2026-03-03

• Baseline: Anomalies are relative to the 1951–1980 global average (NASA's standard baseline)

• Tool: Python (matplotlib + pandas), run in Google Colab.

• Key context from NASA press releases:

2024: +1.28°C — warmest year on record (NASA, Jan 10, 2025)

2025: +1.19°C — effectively tied with 2023 as 2nd warmest (NASA, Jan 14, 2026)

2024's record followed 15 consecutive months of monthly temperature records (Jun 2023–Aug 2024)

• 1.5°C threshold line note: The dashed red line shows ≈1.5°C above pre-industrial (1850–1900). Converting between baselines is approximate — NASA's FAQ (as of Jan 2025) says you can add ~0.19°C to a GISTEMP anomaly to approximate the anomaly relative to 1850–1900. So 1.5°C pre-industrial ≈ 1.31°C in GISTEMP units. This conversion may shift slightly as methodology evolves.

• Paris Agreement: Adopted Dec 12, 2015 at COP21; entered into force Nov 4, 2016. Annotated at 2015.

• Top 3 warmest years are computed dynamically from the dataset — not hardcoded. If NASA revises the data, the chart updates automatically.

• Citation: GISTEMP Team, 2025: GISS Surface Temperature Analysis (GISTEMP), version 4. NASA Goddard Institute for Space Studies. Lenssen et al. (2024), J. Geophys. Res. Atmos., 129(17), e2023JD040179.