4 Wins For Earth

The pesticide dichloro-diphenyl-trichloroethane was widely used in the 1940s. Better known as DDT, it was used to kill disease-carrying mosquitoes and pests that harm crops.

By the 1960s, environmentalists noticed that DDT was causing problems. Rachel Carson’s 1962 book, Silent Spring, outlined the harmful effects of DDT, including the deaths of birds of prey like osprey and bald eagles. DDT collects in the fatty tissues of each animal that eats it, and it accumulates in the tissues of animals at the top of the food chain—like birds of prey. Once in the birds’ systems, DDT caused their eggshells to thin, and most chicks died before hatching.

DDT was banned in 1972. Since then, U.S. populations of many birds of prey have rebounded.

The pesticide known as DDT was used extensively in the 1940s. People sprayed it far and wide to kill disease-carrying mosquitoes and pests that harm crops.

But by the 1960s, environmentalists noticed that DDT was causing problems. Rachel Carson’s 1962 book Silent Spring described its harmful effects. The pesticide collects in the fatty tissues of any animal that eats it, Carson’s book explained. It wasn’t enough to harm small animals that ate plants treated with DDT. But birds of prey, like osprey and eagles, hunted many of these smaller animals. That meant more and more DDT was collecting in their bodies. DDT caused female birds to lay eggs with thinner shells than usual. Most chicks died before hatching, and bird populations suffered as a result.

Carson’s book caught people’s attention, and DDT was banned in 1972. Since then, many birds of prey have recovered their numbers in the U.S.

Ozone is a molecule made up of three oxygen atoms. It gathers in the ozone layer of Earth’s atmosphere, which keeps most of the sun’s harmful ultraviolet rays from reaching the surface. It’s like sunscreen for the entire planet.

In the early 1980s, scientists noticed a hole in the ozone layer above Antarctica. Chemicals called chlorofluorocarbons (CFCs) were to blame. CFCs were widely used in the 1970s and 1980s in hairspray and appliances like refrigerators. When CFCs enter the atmosphere, they release chlorine atoms. Chemists Frank Sherwood Rowland and Mario Molina predicted this problem in 1975, showing that a single chlorine atom can destroy up to 100,000 ozone molecules!

Today, the ozone layer is on the mend. In 1989, the United Nations’ Montreal Protocol prohibited the creation and use of CFCs worldwide.

Ozone is a molecule made up of three oxygen atoms. It gathers in the ozone layer of Earth’s atmosphere. The ozone layer protects Earth’s surface from harmful ultraviolet rays emitted by the sun. It’s like sunscreen for the entire planet!

In the early 1980s, scientists noticed a hole in the ozone layer above Antarctica. Chemicals called chlorofluorocarbons (CFCs) were to blame. In the 1970s and 1980s, CFCs were used in hairspray and in appliances like refrigerators. When CFCs enter the atmosphere, however, they destroy ozone. Chemists Frank Sherwood Rowland and Mario Molina had predicted this problem. In 1975, they demonstrated that a single chlorine atom from a CFC can break apart 100,000 molecules of ozone!

Today, however, the ozone layer is on the mend. In 1989, global leaders at the United Nations agreed to end the use of CFCs worldwide.

Whenever you flip a light switch, turn on a TV, or charge your phone, you’re using electricity. Today, it’s more likely than ever that some of your electricity is created via renewable energy sources instead of by burning fossil fuels, like coal and petroleum. Burning fossil fuels releases carbon dioxide. Carbon dioxide and other greenhouse gases collect in the atmosphere and trap heat, which warms the planet.

Solar panels, wind farms, and hydroelectric power plants create electricity without releasing greenhouses gases. These renewable energy sources do so using abundant natural resources—sunlight, wind, and running water.

Renewable energy usage is growing worldwide. In 2000, renewable energy sources accounted for only 1 percent of U.S. energy consumption. That rose to 12 percent in 2020. So far, the Central American nation of Costa Rica is winning the race: Over 95 percent of its electricity comes from renewable sources. The country plans to overhaul nearly every aspect of its infrastructure and economy to stop emitting greenhouse gases by 2050.

Whenever you flip a light switch, turn on a TV, or charge your phone, you’re using electricity. Most electricity is generated by burning coal, petroleum, and other fossil fuels. But burning these fuels releases carbon dioxide, a greenhouse gas. Greenhouse gases collect in the atmosphere and trap heat, warming the planet.

Today, though, that’s starting to change. It’s more likely than ever that some of your electricity comes from renewable sources. Solar panels, wind farms, and hydroelectric power plants create electricity without releasing greenhouses gases. Instead of fossil fuels, they use abundant natural resources: sunlight, wind, and running water.

Renewable energy usage is growing worldwide. In 2000, it accounted for only 1 percent of the electricity used in the U.S. That rose to 12 percent by 2020. And some countries have gone much farther. The Central American nation of Costa Rica now gets more than 95 percent of its electricity from renewable sources. The country plans to make major changes so that it can stop emitting greenhouse gases entirely by 2050.