source 2.6% of the world’s surface area http://www.newgeography.com/content/001 ... red-cities New Geography http://www.newgeography.com/content/0... (GRUMP) http://www.newgeography.com/content/001 ... red-cities 1.2 million square kilometers 97% of the world http://www.newgeography.com/content/001 ... red-cities 1.2 million square kilometers a mere 2.7%