D3-based take on the Climate Spiral by Ed Hawkins http://www.climate-lab-book.ac.uk/spirals/
Extended with Carbon Budget and Concentration Spiral by
Robert Gieseke and Malte Meinshausen
PRIMAP group, Potsdam Institute for Climate Impact Research, Germany & Australian-German Climate & Energy College, The University of Melbourne, Australia
Based on GPL-licensed D3 example code by Mike Bostock.