September 12, 2013 — Larger animals are more energy efficient than smaller ones — a phenomenon known as Kleiber’s Law — and it’s long been assumed that cities follow a similar pattern. A research team led by Boise State economics professor Michail Fragkias recently tested the notion using data on carbon dioxide emissions as a proxy for energy and surprisingly found no energy efficiency economy of scale between big cities and small ones. The discovery suggests potent opportunities for increasing efficiency through strategic growth as cities’ share of global population booms from just over 50 percent today to a projected up to 90 percent in 2100. Photo by Camerons Personal Page (Flickr | Creative Commons)