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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.
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 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.
