Imagine the data you’d get from recording the original Captain’s logs from every Royal Naval vessel from the First World War: location, temperature and time providing a unique record of climate change. The excellent Old Weather has been crowdsourcing every one of those log books - and the result, created by Simon Tokumine using CartoDB, is a fascinating insight into the British Empire at war - albeit of the records which have survived. Old Weather has moved onto US ships in the Arctic now - see how they’re doing here