From the tongue of the Mer de Glace to the world’s glaciers : 20 years of progress in measuring glacier mass changes from space

In 2004, we painstakingly measured the thinning of a single glacier tongue (the Mer de Glace, Mont-Blanc) from pairs of SPOT (CNES) satellite optical stereo-images. It then took us nearly 20 years before we managed to up-scale such observations to the global scale. In this presentation, I will illustrate the advances (in terms of data availability and processing) and all the collaborative work that led to a spatially-resolved and almost complete estimation of mass changes for the more than 200,000 glaciers on Earth. These new data paint a global picture of accelerating glacier mass loss since 2000 and pave the way toward improved projections of future glacier mass and sea level contribution.