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Earth and climate.

Explore Earth’s structure, climate, and its changes through explanations, indicators, and authoritative scientific sources.

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Articles and explanations

Earth and climate Explainer

How NOAA measures atmospheric CO₂ at Mauna Loa

At Mauna Loa, NOAA measures the dry-air mole fraction of CO₂: a way of quantifying the gas that prevents changes in temperature, pressure, or water vapor from distorting the comparison.

4 min read18 Oct 2026

Earth and climate Guide

What a temperature anomaly means

Zero on a climate graph is a reference point. Learning to read it changes how we interpret the entire curve.

5 min read17 Oct 2026

Earth and climate Explainer

How we know what lies inside Earth without visiting it

Seismic waves, minerals, and gravity allow us to test an image of a planet we cannot observe directly.

5 min read17 Oct 2026