The Climate Research Unit at UEA have released this temperature dataset as a KML file. Lots of "use Google Earth to do..." press coverage but I think the data could equally be used in Marble, no? There was a request along these lines a few years ago "climate change predictions on a map": https://bugs.kde.org/show_bug.cgi?id=194133 Data portal here: http://www.cru.uea.ac.uk/cru/data/crutem/ge/ Direct link to KML: http://www.cru.uea.ac.uk/cru/data/crutem/ge/CRUTEM4-2013-03_gridboxes.kml Article about the data and its uses: http://www.realclimate.org/index.php/archives/2014/02/exploring-crutem4-with-google-earth/
The KML files unfortunately only work partially (the popups don't get displayed :-(