Period 6: Accelerating Global Change and Realignments, c. 1900 to the Present Key Concept 6.1 Science and the Environment Rapid advances in science altered the understanding of the universe and the natural world and led to the development of new technologies. These changes enabled unprecedented population growth, which altered how humans interacted with the environment and threatened delicate ecological balances at local, regional, and global levels. Researchers made rapid advances in science that spread throughout the world, assisted by the development of new technology. New modes of communication and transportation virtually eliminated the problem of geographic distance. New scientific paradigms transformed human understanding of the world.