Syndicate content

growth

Urban Careers and the Twenty-Ninth Day

Dan Hoornweg's picture

Lily pads on lakeA helpful way for young math students to grasp the concept of exponential growth is to look at water lilies growing on a pond. They grow exponentially and double in area each day. If they will fully cover the pond by the 30th day, on what day is the lake half covered? The twenty-ninth day[1].
 
This year I had the honor of teaching 4th year energy systems students who will graduate later this month (their blogs on energy issues will be presented on this site over the summer). These graduates are particularly essential. During their careers they will be part of the world’s largest ever city-building spree. Their task will be to again double the world’s cities.

The Buzz of Cities

Dan Hoornweg's picture

BeeFor bees, bigger hives are better. 

Last week researchers at the University of Arizona published their findings: bees of bigger hives have more information and forage better. With improved communications, bees from the bigger hives sent new foragers to known resources up to four hours earlier than bees from smaller hives.1

This better communications also seems to work in bigger cities. Geoffrey West and the Santé Fe Institute provide impressive modeling on the scaling of cities. Double the size of a city and you get 1.15 times the growth of economy, patents and innovation. And as long as you can keep congestion and pollution in check, you can get this economic growth at only 0.85 times the cost of additional infrastructure. In other words, larger cities have a disproportionate impact on a country’s communications, and therefore a bigger impact on economy and culture.