This Issue:

Table of Contents

Cover Story

Cover Story - Spanish Version

Mini-Lesson

Comprehension Quiz

Teacher's Guide and Worksheets

Welcome to the City of the Future

Spanish Translation

Angelique LeDoux

The past year was the hottest on record in the United States. Most scientists say that human activities have played a significant role in global warming. Much of our daily activity overloads the atmosphere with carbon dioxide (CO2): driving big cars, using computers, building skyscrapers, houses and schools. CO2 and a few other gases trap solar heat near Earth's surface.

Wealthy countries are the biggest contributors to CO2 overload. About 25% of the world's CO2 output last year came from the U.S. But scientists, architects, business leaders and lawmakers are looking for ways to fix the problem. As of April 12,mayors in 453 U.S. cities had signed an agreement to reduce pollution. They are creating programs to encourage more Earth-friendly living. San Francisco, California, has banned Styrofoam food containers. New York City is converting a landfill into a lush park. And Chicago, Illinois, has more than 200 grass roofs. More energy-smart communities are on the rise. Here's what a town could look like in the near future if people were to put more energy into taking care of the environment.

The Green House

Energy-saving homes and buildings conserve water and energy. Grass- and plant-covered rooftops absorb less heat and act as filters for rainwater harvesting. Rainwater is collected and stored. It is later used to flush toilets and water plants. Open windows act as air conditioners. Geothermal heat pumps use water to cool the home in summer and keep it warm in winter. Some homes are made from recycled materials. In green schools, teachers use hands-on lessons to teach kids about the environment. Stores and offices are within walking distance of homes. Markets sell locally grown food.

Clean Power

Solar panels, wind turbines, hydropower and geothermal energy use the power of nature to generate electricity and make things run. Solar panels turn the sun's energy into electricity to power homes. Wind turbines, often found on farms, convert the energy of the wind into electricity. Hydropower harnesses energy from flowing water. Geothermal energy draws heat from deep within the Earth's interior. These sources release much less CO2.

Alternative Transportation

Cars, trucks and buses run on renewable fuels. Ethanol is made from corn or grasses. Biodiesel fuel comes from soybeans and cooking grease. Alternative-power vehicles and mass transit, like light-rail trains, reduce the use of gasoline. Hybrid cars combine fuel-burning engines and battery-powered motors. Electric cars run on batteries that are charged the same way as laptop computer batteries.

Open Spaces

Backyards are used for composting. Food, paper and yard waste break down quickly to create rich soil for gardening. Recycling is as common as taking out the trash. Even land is recycled. Former airports and dumps are cleaned up and turned into parks.

Here is a look at some ground-breaking projects around the country.

Next: TIME for Kids Earth Day Photo Contest Winners