Photograph of Devonian rugose corals from New York State.

Quick Guides & FAQ

Find quick answers here to all of your Earth science questions.

Last updated August 31, 2021.

Image above: Devonian-aged rugose corals from New York State.

Quick Guides to Earth Science

Quick Guide to Common Fossils

Frequently Asked Questions (FAQ)

Climate and Energy

Fossils and Ancient Life

Climate and Energy

What Causes Climate Change?

Illustration that shows connections between all of Earth's spheres: atmosphere, hydrosphere, geosphere, and biosphere.

Why is Carbon Dioxide Called a Greenhouse Gas?

Illustration that shows Earth inside of a greenhouse.

How Do We Know That Humans are the Major Cause of Global Warming?

Photograph of a person holding a chunk of coal in front of a power plant.

Does the Ozone Hole Cause Global Warming?

How Can We Predict Future Climate Reliably When We Can’t Even Predict Next Week’s Weather Very Accurately?

Is Climate Change Too Big or Too Far Along to be Stopped?

What is the IPCC?

Is the Sun Causing Global Warming?

Are Volcanoes Causing Global Warming?

Are Orbital Changes Causing Global Warming?

Why is Sea Level Rising?

Geology

How do scientists date rocks and fossils?

Photograph of a crinoid fossil.

How do metamorphic rocks form?

Up-close photograph of gneiss, a type of metamorphic rock.

What is karst topography?

Up-close photograph of gneiss, a type of metamorphic rock.

Fossils and Ancient Life

Mammoth vs. Mastodon: What is the Difference?

Photograph of models of a mammoth and mastodon.