The

Greenhouse

Effect

It was the 1820s when French

mathematician and physicist Joseph

Fourier proposed that energy reaching

the planet as sunlight must be balanced

by energy returning to space since

heated surfaces emit radiation.

But some of that energy, he reasoned, must be held within the atmosphere and not return to space, keeping Earth warm.

1768
1830

Joseph Fourier

French mathematician and
physicist

But some of that energy, he reasoned, must be held within the atmosphere and not return to space, keeping Earth warm.

He proposed that Earth’s thin covering of air—its atmosphere—acts the way a glass greenhouse would. Energy enters through the glass walls, but is then trapped inside, much like a warm greenhouse.

the greenhouse
analogy

The more greenhouse gases there are, the more heat and energy is kept within Earth’s atmosphere.

Experts have since pointed out that the greenhouse analogy was an oversimplification, since outgoing infrared radiation isn’t exactly trapped by Earth’s atmosphere but absorbed.

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