Slide image: Line graph, entitled "World Population: 1950-2050" showing the world population growing between 1950 and 2050. The population was a little over 2.5 billion in 1950 and is projected to be over 9 billion by 2050.
Source: U.S. Census Bureau, International Data Base, 2008 First Update
Slide image credit: U.S. Census Bureau
Background image: Photo showing the sun setting over the ocean and a dramatic sky
Background image credit: © 2009 JupiterImages Corporation
Design by: Adrian Apodaca, National Science Foundation