Clyde Burnett, Peak to Peak. This will be a reminder of the basic science of climate change. These facts should be useful in convincing political candidates and other voters that you have good advice about climate change.

We need to have our planet home in energy balance. The radiation physics for the Earth’s outward radiation to balance that from the sun requires its radiation temperature to be -18o Celsius (about 0o Fahrenheit). That effective radiation surface is at about 20,000 ft altitude.

But our global average surface temperature is about 15oC. That is a whopping 33oC higher. That means that our atmosphere must have a very large Greenhouse Effect. (Because it behaves like the place where we grow flowers and vegetables in winter.) 

Some folks like to say that this is an Intelligent Design prepared by some Supreme Being. Actually, the life forms of humans and the plants and animals that support us have slowly evolved to this temperature and climate. In any case, it is critical that it not change lest we all become extinct. When human populations were not more than about four billion, we could pollute with only slight effects on our environment. But at seven plus billion, we are a critical part of Nature. We can’t alter the universal laws of Nature, but humans are now in control of some of the ingredients, like the composition of our atmosphere that controls the amount of ozone that protects us from solar ultraviolet or makes the Greenhouse Effect.

The atmosphere is composed mostly of oxygen and nitrogen suitable for life. Their molecular structure does not contribute to the Greenhouse Effect.

The trace atmospheric molecules of water, carbon dioxide, methane, and others with structure appropriate for infrared absorption are the greenhouse gases. They absorb precisely at the part of the spectrum where Earth’s radiation is at a maximum. The heat trapping is large where these are of maximum density in the lower atmosphere. Water vapor is the most abundant greenhouse gas because 70% of the Earth’s surface is water. The others trap a small amount of heat that adds to the ocean evaporation and controls the large amount of water vapor greenhouse effect. It is the more than 40% increase in carbon dioxide (CO2) from burning fossil fuels that is producing climate change. The increased thickness of the greenhouse gas is moving the effective radiation surface to higher and colder altitudes. That is destroying the planet’s energy balance.    

Fortunately, we avoid a runaway greenhouse effect due to the 10-day water cycle of evaporation and precipitation. There is also a century long carbon cycle of tree photosynthesis sequestering and decay, and much longer cycles of carbon trapping and escape in soils and oceans. This means the emitted CO2 today will trap heat in the atmosphere for a very long time.  

The increased heat trapping is melting glaciers and polar ice. The meltwater and thermal expansion of oceans is causing sea level rise. The air temperature has warmed about 1oC. The limit before irreparable damage is 1.5-2 oC.

It is the temperature increase that is causing the terrible brushfires in Australia. (See photo of smoke during worst of fires.) 

It is the increased evaporation from the increasingly warmed Gulf that is causing tornadoes in southern states.    

We manufactured some new molecules like CFCs to develop air conditioning. And we fiddled with the chemistry by burning fuel with carbon molecules to release energy for heat, electricity, and transportation. We fixed the stratospheric ozone problem with the international Montreal Protocol that stops the manufacture of CFCs. Now we need to get an international agreement to control the CO2 increase of the Greenhouse Effect.

(Originally published in the February 6, 2020, print edition of The Mountain-Ear.)