Scientists agree: 2023 was Earth’s hottest year in the modern record. And it wasn’t particularly close. To come to these conclusions, experts collect and analyze data from numerous sensors, going back to the 1800s (and proxy data from even earlier). Some of the sensors are on land, some are now in orbit, and others bob about at sea. The maps above depict measurements from the latter two, and they had scientists scratching their heads halfway through the year.
Using data from Coral Reef Watch, a project of the National Oceanic and Atmospheric Administration (NOAA), Tim Meko and The Washington Post mapped sea surface temperature anomalies during 2023. Climate scientists often rely on anomalies—differences from a long-term average—to understand where and by how much local measurements deviate from a standard baseline.
Shades of orange and red dominate, showing much of the world’s oceans were warmer than average. Regions where temperatures were extremely warmer than usual are shown in darker purple and magenta. Such widespread warmth contributed to new global records. (And the temperatures remained high at the end of 2023.) Warming oceans impede the growth and longevity of sea ice and make destructive coral bleaching events more likely. They can also enhance the frequency and potency of tropical storms.
The combination of reliable, insightful data and a clean, understandable design makes these maps as alarming as they are intuitive. You can view more maps and read additional analyses from The Washington Post. You can also visit NOAA’s Coral Reef Watch for updated imagery based on the same data.
More to Explore
- Learn more about temperature anomalies and why scientists prefer them to absolute temperatures.
- See how coral bleaching events are associated with warmer water.
- Compare year-to-year global temperature changes.
