Clyde Burnett, Boulder County.   Humanity needs to be thankful for the planet home on which we have evolved. Of the planets in our solar system, Earth’s orbit position is the most favorable for the evolution of our species. Its energy balance of radiation yields a balance between the freezing and boiling points of water, permitting life forms dependent on this substance.

This is due largely to our atmosphere and its greenhouse effect that traps heat equivalent to 33 C degrees. There are trace constituents that absorb infrared radiation at just the maximum wavelength of Earth’s heat radiation. It is the 10-day water cycle of evaporation and precipitation that produces the necessary amount of water vapor greenhouse gas. The other trace amounts of carbon dioxide, methane and nitrogen compounds controls the water vapor to an amount that is most favorable for human evolution.

Our neighboring planets Mars and Venus do not quite satisfy our requirements. Venus’ orbit was too close to the sun for our 10-day water cycle, resulting a runaway greenhouse effect. Mars lacks a magnetic field of a strength that protects its atmosphere from the solar wind; it has no greenhouse effect. There is no planet B!

We have evolved to a population of 7 Billion, sufficient for our activities to make us part of Nature. We now control the strength of the greenhouse effect by our production of carbon dioxide from burning of fossil fuels. Our self-destructing industrial activity has increased this concentration by more than 40 percent without regard to the Earth’s response; we have global warming, with resultant melting of glacial and polar ice, sea level rise, and extreme weather. We are in great danger of losing our home on the blue marble.

(Originally published in the November 15, 2018, print edition of The Mountain-Ear.)