Sailing ships tell us more about global warming

Posted on Wednesday 4 February 2026

A new record of historical global temperature is pushing our understanding of our role in climate change back to the very beginning of the industrial revolution.

The GloSAT project, with contributions from Chemistry's Professor Kathryn Cowtan, has combined citizen science to digitise old weather records from sailing ships and applied the latest machine learning and data analysis techniques to turn these records into a measure of global warming. In doing so the project has faced major challenges in dealing with the different environments in which sailors measured temperatures on different ships.

Early weather station observations on land have also been used, with similar problems arising from before the standardisation of weather station enclosures. Careful data analysis has allowed a first attempt to combine all of these data to measure temperatures back to 1781, close to the start of the industrial revolution.

This new approach offers significant improvement over equivalent existing records, which typically report temperatures back to the mid-late 1800s.

It should be noted that many of the records used in this project were from ships owned by the East India Company, which was complicit in oppression and slavery.