What Would Earth Be Like If Humans Disappeared?

What Would Earth Be Like If Humans Disappeared?

We humans tend to think of Earth as "ours." But the planet was here long before we came on the scene, and it will probably be here long after we leave. In fact, our existence is a mere blip on Earth's time scale: the Earth is 4.5 billion years old, and modern humans have only been on it for about 200,000 years. If we disappeared, it wouldn't take long for evidence of our existence to disappear too. Humanity's wood structures would be gone within a century, and all of our cars, bridges, and other metal structures would rust to nothing a while later. It's humbling to think how quickly the whole of human creation could disappear without us around.

Earth in 100 Million Years

If space travelers encountered Earth millions of years in the future, what would they see?

06:27

from It's Okay To Be Smart

What Would Happen If Humans Vanished?

How long would it take for our cities to crumble?

04:08

Key Facts In This Video

  • 1

    If humans disappeared, more than 20 billion farm animals would break out of their enclosures to find food. (0:14)

  • 2

    100 years after the disappearance of humans, most wood structures would be gone, and steel ones wouldn't be far behind. (1:25)

  • 3

    Without humans, human structures would last longer in the desert, where there's no moisture to promote rusting or support decomposing organisms. (2:52)

What If Humans Had Never Existed?

If humans never evolved in the first place, the world would be very different.

02:36

Key Facts In This Video

  • 1

    If humans had never existed, the night sky would look a lot darker. (0:19)

  • 2

    Without humans, the Earth would not have undergone global warming, and may have entered another ice age. (0:57)

  • 3

    In the absence of Homo sapiens, one of our evolutionary cousins may have evolved to dominate the planet. (1:46)

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