In 2013, more than 16,000 Old Weather-Arctic volunteers transcribed handwritten Arctic ship logs, while 275,000 scanned pages contained about 23 million weather and sea-ice observations

Imagine a retired teacher in Ohio and a university student in Manchester studying scanned images of 19th-century ship logs and trying to decipher a sailor’s messy handwriting. It may seem like just a hobby, but in reality, it was scientific work and it grew quickly. By March 2013, this crowdsourcing project called “Old Weather-Arctic” had become something huge. More than 16,000 volunteers were helping transcribe more than 275,000 handwritten pages from old ships of the U.S. Navy, Coast Guard and Coast Survey. Together, these pages contained almost 23 million weather and sea-ice observations. A 2019 Journal of Climate study, ‘Arctic Sea Ice Volume Variability over 1901–2010: A Model-Based Reconstruction,’ used just this kind of transcribed data to help reconstruct more than a century of Arctic sea ice history. That extended the record for sea ice thickness from 40 years to 110 years, giving scientists a much longer baseline to judge today’s melt

Why anyone cared about old ship logs

Before satellites began monitoring the Arctic in 1979, scientists had almost no continuous record of sea ice. The researchers turned to an overlooked source: sailors often maintained meticulous weather logs. Captains kept hourly records of wind speed, temperature, and sea-ice conditions in the 1800s and early 1900s because their lives depended on it. These notes sat in archives for decades, unreadable by computers because 19th-century cursive is too messy for machines to read. That’s where human volunteers came in. The method was described in a 2009 Bulletin of the American Meteorological Society paper, 'Marine Observations of Old Weather,' which showed that ship logbooks could help fill gaps in historic weather records, if anyone was willing to take the time to patiently transcribe them by hand.

Meet the volunteers who cracked the code

The U.S. Arctic version of this project was led by University of Washington climate scientist Kevin Wood, a former merchant mariner, working with the National Archives under an agreement established in 2011. The project launched in October 2012. Two interns at the National Archives took photos of each page of the logbooks, which volunteers around the world transcribed via a site called Zooniverse.

Zooniverse is a large citizen-science platform. A 2014 paper describes the platform as the world’s largest citizen science system, which allowed ordinary people to help carry out tasks that would otherwise take decades for professional scientists to do on their own. Old Weather volunteers began as “cadets” and progressed to lieutenant and captain as they did more transcriptions. Even interns at the National Archives discovered flowers pressed in a logbook dating back to 1891. One of the notable finds was the logbook from the USS Jeannette, which left San Francisco in June 1879, became trapped in Arctic ice within months and drifted for about 21 months while its 33-member crew recorded hourly scientific observations. The entire logbook was transcribed by volunteers in March 2013. The same ship once got stuck in 20 feet of sea ice in water that is now often ice-free in summer.

From handwriting to hard climate data

Here is where the story grows bigger than a history project. Back in 2013, Wood was working with polar scientists at the UW’s Applied Physics Laboratory to include some historical sea ice records into their Arctic sea ice models, which go all the way back to the early 1900s. That work contributed to the 2019 study mentioned above, which integrated a century-long computer model with some historical sea ice observations, many recovered from these logbooks, to check its estimates of Arctic sea ice volume back to 1901, turning a 40-year satellite record into a 110-year one. This matters because historical data helps scientists know whether a similar major event has happened before.

Why this is still relevant to us today

You don’t need to be a scientist to appreciate this. It shows what happens when ordinary people, armed with an internet connection and patience, help unlock information that has been sitting untouched for over a hundred years. The transcribed observations were also folded into the International Comprehensive Ocean-Atmosphere Data Set, a global climate archive, and volunteers were promised credit on any resulting scientific publications. It shows a hopeful something too. Climate science can feel remote, as if it were something only lab experts could work with. This project showed that anyone with a laptop could contribute real, usable data to real research. The words, painstakingly typed out by volunteers, are now part of the way scientists understand a changing Arctic. The next time climate change seems too complex to track, remember this story. Sometimes important scientific work starts small, with someone reading old handwriting on a quiet Tuesday night.