---
title: A warmer world
description: NASA's global temperature index, compared with the 1951–1980 average.
styles: [air]
title_image:
  src: https://images.unsplash.com/photo-1541180413652-36d68a04c873?crop=entropy&cs=tinysrgb&fit=max&fm=jpg&ixid=M3wxMTE0NDQ4fDB8MXxhbGx8fHx8fHx8fHwxNzk0MjQ3MjMxfA&ixlib=rb-4.1.0&q=80&w=1080
  alt: "Blue and white ice at a glacier lagoon"
  caption: "Glacier ice meets the water in a lagoon."
  fit: cover
  width: 1080
  height: 432
  credit:
    author: "Stephen"
    author_url: https://unsplash.com/@srkraakmo?utm_source=daniel-ai-skills&utm_medium=referral
    source: Unsplash
    source_url: https://unsplash.com/photos/water-splash-near-iceberg-DMjeSRTfhkg?utm_source=daniel-ai-skills&utm_medium=referral
---

The annual global temperature anomaly compares each year with the 1951–1980 average. It is a departure from that baseline, not an absolute temperature.

```chart
type: line
title: Global temperature has risen since the late nineteenth century
data: { csv: data/global-temperature.csv }
encoding: { x: year, y: anomaly_c }
axes:
  x: { format: year }
  y: { label: Temperature anomaly, unit: °C }
```

*Source: [NASA GISS GISTEMP v4](https://data.giss.nasa.gov/gistemp/), annual land–ocean temperature index, downloaded 9 November 2026. Credit: NASA GISS GISTEMP Team.*

## Read the baseline correctly

Zero means the 1951–1980 average. A value of 1 means one degree Celsius above that baseline. It does not mean an absolute temperature of one degree. This is an annual global index; individual places and months differ. The frozen CSV ends in 2025, so it does not mix an incomplete current year with completed annual means.