If you ever meet a climate scientist, give them a hug. Not only is the work important, it involves an absolute mess of variables—emissions, maybe sequestering those emissions, atmospheric patterns, maybe geoengineering that atmosphere. Data is often sparse or non-existent. So give them a hug. The data problem is particularly acute in the oceans. A key part of figuring out how much the planet has warmed, and how drastically we need to cut emissions, is determining how the sea is changing.