Crowdscience

On the banks of the St Lawrence River in Quebec stands a 100-year-old lighthouse. While initially built to help boats navigate one of Canada’s most difficult waterways, the Point-de-Père site now also holds a different responsibility: it is a key reference for measuring sea levels around the entire North America continent. But this is all set to change. With the development of new satellite technology, the tricky task of measuring sea levels is being updated - which could mean mountains around North America get brand new official heights. In this episode we revisit a question from CrowdScience listener Beth, who wondered about the elevation signs she saw scattered along a mountainous road, indicating how high above sea level she was. As sea levels rise, will all the elevation signs need repainting? And how do you measure sea level, anyway? The height of an enormous pile of rock like Ben Nevis, or Mount Everest feels unchangeable. But we measure them relative to the nearest patch of sea, which is where our s