The growth of scientific knowledge has played a big role in helping people care about the environment. It gives us clear proof of how our actions affect the Earth.

Here are some important points:

1. Facts and Figures:

   • A study from 1967 showed that since 1880, the Earth's temperature has gone up by about 0.5 degrees Celsius.
   • Reports found that around 75% of the world’s forests have been cut down, which raises concerns about losing different plant and animal species.

2. Raising Awareness:

   • In 1962, Rachel Carson published a book called "Silent Spring."
     It used scientific research to show how harmful pesticides can be. This helped lead to the U.S. banning DDT by 1972.
   • The first Earth Day in 1970 brought together more than 20 million people. This showed how many people were starting to care about the environment, thanks to scientific evidence.

3. Changes in Laws:

   • Following these efforts, the U.S. passed over 20 important laws to protect the environment.
     This includes the Clean Air Act (1970) and the Clean Water Act (1972).

These important steps helped start modern environmental movements that are based on science.