In the following videos scientists explain why they need to enlist your help and how the work you are doing can contribute towards their research.

Video transcription

[Clive Wilkinson] The Old Weather project isn't about proving or disproving global warming. We need to collect as much historical data as we can over the oceans, because if we wish to understand what the weather will do in the future, then we need to understand what the weather was doing in the past.

[Philip Brohan] We're simply attempting to gather more information about historical weather variability, to improve our understanding of all forms of weather variability in the past and so improve our ability to predict weather and climate in the future.


Scientists input weather readings into a database in order to identify weather patterns and extremes. This allows them to test climate projections of how the Earth's weather will develop in the future against how the climate has behaved in the past.

Video transcription

[Rob Allan] One of the major pushes that we've done on this is with the English East India company in the period from the 1780s to the 1830s. About half of the logbooks that exist in the British library for those ships that trade between the UK and India or China have instrumental measurements that we're after on them.

[Philip Brohan] Charles Darwin's voyage on the Beagle is most famous for his great work on evolution, and his great zoological work. But actually Robert Fitzory, the Captain, and his crew also recorded the weather in their logs of the records at every point the ship visited.

[Rob Allan] We've also been looking at late 19th and early 20th century Antarctic expeditions which go down, obviously, to a region where we have particularly sparse data in the southern hemisphere.

[Philip Brohan] The numbers themselves give us recordings of temperature and pressure at a particular location - wherever the ships are. If we have hundreds or thousands of points' location data from ships, we feed that data into one of our computer models of the atmosphere, and out of that computer model of the atmosphere comes a weather map.

[Rob Allan] But instead of feeding in the current data to look at the future, you're putting in the data in the past - or some of the variables - and you're reusing the model and the understanding of the physics of the ocean atmosphere system that's in the models to reconstruct all the other variables that are interrelated physically. So you can get a 3D picture of the weather all over the globe.

[Philip Brohan] If we're worried about extreme weather - unusual events, very large heatwaves - then that perspective, that extra length of our records - give us more information about how likely events like that are to occur in the future.


The more people that take part in Old Weather, the more accurate the extracted data will be. Each logbook will be looked at by more than one person allowing mistakes and errors to be filtered out.

Video transcription

[Arfon smith] Crowdsourcing gives you two things. It gives you capacity to do more work, and it gives you error checking in the data you collect. Probably the best way to illustrate this is that if I'm transcribing a log book from a ship, and I'm transcribing weather events - temperatures, pressures- it's very easy for me to mistranscribe a temperature and pressure when reading numbers off a page. But if you also transcribe it, and three or four other people, then between us we're probably going to get the right answer. So we correct for the person who made the mistake by getting repeat transcriptions.

You get this error checking, but you also get by having tens of thousands of people the ability to go through tens of thousands of more logbooks in the same amount of time.

[Caption] How long would it take one person to do all the work?

[Arfon] Let's get a calculation. Let's say 2 minutes per log, so that's 500,000 minutes for 1 transcription. Divided by 60 minutes... so what's a working day? 8 hours? So that's a 1000 days, but that's for one transcription. Let's be conservative and say we need 10 repeats. So that's 10,000 days, so if we were working without holidays 28 years of effort. That's quite a long time, but we would hope to do it in less than 6 months. The great thing about this is that we have tons more logbooks which need transcribing, so this is just the beginning.


The majority of the Earth's surface is water making weather readings taken at sea as important as those taken on land. The oceans absorb and transport large amounts of heat and water around the world which affects our weather. Tracking any changes in temperature helps us to predict how our weather will be affected.

Video transcription

[Philip Brohan] If you look at your globe or your map of the world, then you'll realise there's quite a lot of sea out there. In fact, 70% of the world is sea. In some respects if you're looking at many aspects of the weather, it's better to have observations from the sea than on land. Because the ocean is such a good store of heat, if you actually have a good model of how the climate works it's possible in many respects to work out what's going to happen on land based on sea observations. In other words, we can propagate the sea temperature over land as the energy from the sea is carried over the land by the winds, and get a lot of information about what's going to happen on land, just from sea data.

[Philip Brohan] The sea is a very homogenous medium - it doesn't have any mountains in it, or any valleys in it, so an observation on the sea very often represents a large area. Whereas in land based areas there are very noticeable microclimates, so particular points may be representative of smaller areas, so sea observations can be more useful from that point of view as well.


Historic measurements allow scientists to reconstruct weather patterns and extremes from the past allowing them to identify changes in the Earth’s climate over time. Ships travelled around the world on voyages of exploration and trade often making regular measurements in areas where no one else was.

Video transcription

[Clive Wilkinson] Anything you read in a logbook, you can be sure that it's a true and faithful account. In fact, it was an offense to falisfy a log. They were reasonably well educated men - they could read and write, they could navigate, they had a basic understanding of mathematics. Many of these sailors and officers went to sea as teenagers or pre-teenagers. They learned their trade on deck, they learned how to navigate and filling in the logbook was part of the administration of the ship.

[Philip Brohan] If we're interested in finding out or studying a particular period in a particular region of the world, it's very likely that that region of the world will have too few, or no observations whatsoever. So if we produce more observations we can fill in those gaps, improve our historical database and with a bit of luck improve our predictions of future weather.

[Clive Wilkinson] Historical data is important because there are many areas of the world where we don't have sufficient data, and there are many time periods where we don't have data. This fills in the gaps and builds the bigger picture.


Logbooks are difficult for a computer to analyse accurately. Reading handwritten text is a skill that people and not computers excel in. Handwriting is often confused and misinterpreted by them, which can lead to errors in the data. Humans are also better at identifying important information.

Video transcription

[Clive Wilkinson] There's probably 250,000 logbooks in this country alone. There are logbooks in America, there are logbooks in South America, in Asia. There are literally billions of observations to be captured. The handwriting can vary from extremely good copperplate, in which case you know it's been written by a clerk, or by someone who is trained in very good writing, or it can be very scruffy. Computers can read printed text... there are idiosyncratic features of the handwriting - it's not printed, and a computer will make no sense of it whatsoever. You start to get into recognising the style of writing, the sorts of words and expressions and phrases they're using.

The ship is actually off the Cape of Good Hope.


The air temperature is 70 - very strong gale, with very high sea running. Ship pitching heavily. And then a few hours later - strong gale with heavy puffs of wind and rain; warship to the northward.

It's like going on a new adventure every time. I never know what I'm going to find in a log book.


The data you extract from the logbooks will be used by scientists, geographers, historians and the public around the world. Anyone with an interest in the data will be able to access it and use it.

Video transcription

[Philip Brohan] The actual logbooks kept on board these ships are now stored in various archives. We need that information digitized - we need to turn it into forms computers can read and understand, and that's where we're looking for the help of the public, to take the numbers written on these documents and turn them into a particular text format. And when we're turned them into text format, we get information that looks like a list of the sorts of information - the port numbers, the pressures, the temperatures that are stored in those particular documents. That list in itself is not enough to give us the understanding of the weather and the climate and the improved predictability that we're after, and so we need to take those measurements and we need to synthesise them with our knowledge of the physics of the atmosphere, and we need to turn them into reconstructed forms of the climate.

[Philip Brohan] And here's a reconstruction of the climate - this one's for 1911, based on a limited number of observations. We take the observations and we reconstruct fields of pressure, wind speed, weather, cloudiness, precipitation, and it's this that we use to give us the physical understanding that we use to make better projections and predictions.