Seeing the environmental forest

Looking back at my first posts, I realized that I had neglected to explain the greenhouse effect.  This post is intended to rectify that omission. First a basic principle: All energy that enters or leaves the Earth's atmosphere must be in the form of radiation.  And yes, that includes heat.  There's no atmosphere in space so heat cannot be lost from the planet via conduction and convection.  The general process is as follows. 1) Energy from the sun (including ultraviolet and visible radiation) enters the atmosphere. 2) About 30% of the sun's radiation is reflected back into space by aerosols in the air (produced by volcanoes and coal-fired power plants) or via snow, ice, and other light-colored surfaces.  Of the 70% that reaches the ground, most is visible light as most ultraviolet is absorbed by the ozone layer. 3) When visible light reaches the ground, the energy is absorbed by the surfaces on the ground.  That absorbed energy is reradiated as inf...

After Joseph Fourier deduced the existence of the greenhouse effect in the 1820s, it took until 1861 before John Tyndall identified the first components of the greenhouse effect as water vapor and CO 2 ( Tyndall 1861 ).  One hundred fifty-two years of research later, we know far more about the absorptive properties of  CO 2  and other greenhouse gases , including water vapor, including how they affect Earth's infrared spectrum.

The existence of Earth's greenhouse effect was first postulated by Joseph Fourier in the 1820s, when he calculated that the Earth should be much colder than it actually is.  Using the Stefan-Boltzmann law, and modern measurements, we can calculate what that temperature should be.  The equation for doing so is