Why don't greenhouse gases also block out some of the incoming rays from the sun, and counteract global warming?

I understand what causes global warming. The sun's rays travel through the atmosphere, hit earth and than bounce back into space. But because of green house gases, not all of the heat bounces back into space, and this makes earth hotter. Why don't greenhouse gases also block out some of the incoming rays from the sun, and counteract global warming?

1 Answer
Jan 9, 2016

Answer:

Greenhouse gases are transparent to the wavelengths of the incoming radiation.

Explanation:

Everything reacts differently to energy at different wavelengths. This is way xrays (very short wave lengths) can travel through your skin while light (short wave lengths but much longer than x-rays) is blocked by your skin.

Incoming solar radiation (visible spectrum for the majority) that heats the Earth is about 1/10th the wavelength of outgoing radiation (infrared or heat). For a gas like carbon dioxide this means that in coming radiation is like an x-ray, traveling cleanly through it, but the out going radiation hits it like a wall, trapping the heat.