The National Archives in Kew has announced that Captain James Cook’s weather reports, which he logged meticulously at noon each day on his voyages to unknown lands, are helping scientists to predict changes in the climate.

Ships’ logs from Cook’s Discovery and Resolution, William Bligh’s Bounty and 300 other 18th and 19th-century explorers’ vessels are being transcribed and digitised in a project that will allow climatologists to trace changing weather patterns.

The records, stored in the National Archives at Kew, contain a unique and highly accurate account of temperature, ice formation, air pressure and wind speed and direction in remote locations all over the world.

There are plenty of land-based weather reports from this period, but very little is known about the climate history of the three quarters of the world’s surface covered by sea.

Dennis Wheeler, the project leader and a climatologist at Sunderland University, said that the thermometer readings were almost always taken in the shade of the unheated cabin and were therefore directly comparable with modern readings.

The absence of marine chronometers, which were invented by John Harrison in the mid-18th century but not widely used until the 19th century, has proved fortuitous for climate scientists. Without knowing the precise time, the captains needed to log very accurate weather details, including wind speed and direction, in order to gauge their longitude. Dr Wheeler told The Times: “Reading these logs gives me a growing respect for the navigation skills of these captains and officers. The lives of everyone on board often depended on the accuracy of their observations.

“Their conscientious and remarkably detailed reporting has given us an invaluable data resource which fills huge gaps in our knowledge about the history of the climate.”

Full Story: Times Online