Pedestrians walk in Brooklyn on an unseasonably warm afternoon in February 2017, when temperatures reached near 60 degrees. To take action against climate change, New York City is requiring large buildings to retrofit their structures to improve energy efficiency. Spencer Platt/Getty Images hide caption
Dishwashers have come a long way since this 1921 model, which was designed mainly to help minimize the drudgery of housework. But today's sleek models are also designed with water conservation in mind. Bettmann/Bettmann Archive/Getty Images hide caption
The Energy Star program started in 1992 to rate the efficiency of computer monitors and now covers dozens of product categories. Paul Sakuma/AP hide caption
A building called Sustainability Base, at NASA's Ames Research Center in Mountain View, Calif., has an energy-efficient design that allows in sunlight. So for most of the year, the interior is illuminated by natural light. Dominic Hart/NASA hide caption
Solar Sunflowers, an art installation, greets visitors to Mueller's commercial and retail hub off of Interstate 35. The panels power a nightly light display and return power to the grid. When the development is complete, five miles of granite trails will connect the residents to its commercial and retail hubs. Julia Robinson for NPR hide caption
A woman in Senegal charges her cellphone using a port in her solar-powered LED lantern. Bruno Déméocq/Courtesy of Lighting Africa hide caption
Scientists say energy-saving compact fluorescent (left) or light-emitting diode (right) light bulbs can have unsavory health effects. PRNewsFoto/OSRAM SYLVANIA hide caption