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

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