- Glass skyscrapers are the primary high-rise style around the world, but they're energy inefficient.
- New towers include a variety of eco-friendly innovations, such as renewable energy generation, solar shading and double-skin facades.
- Due to urbanization, mixed-use skyscrapers are becoming the norm in Japan and China.
David Nicholson-Cole is a Professor in Architecture at University of Nottingham. The views expressed in this commentary are solely those of the writer. CNN is showcasing the work of The Conversation, a collaboration between journalists and academics to provide news analysis and commentary.
(CNN)Slick, glassy skyscrapers cast their shadows over the streets and spaces of cities all over the world.