The science of warming

In the month of June, there were at least two letters to the editor that cast doubt on the science and reality of human-caused global warming – even though the science behind it is both simple and obvious, as related below.

The Earth resides in space at a distance of approximately 93 million miles from the Sun. At that distance, the Solar Irradiation Flux is about 1,365 watts per square meter. While about 30% of that incoming radiation is reflected back into space, the Earth is heated by the 70% of incoming sunlight that is not reflected.

In order to reach a stable temperature, the Earth must also have a means of releasing heat. It does this by its emission of infrared (longer wavelength) radiation. Most infrared radiation emitted from the Earth’s surface does not survive passage through our atmosphere, however, and instead is intercepted by clouds and molecules collectively called the “greenhouse” gases, thereby causing the temperature of the Earth to be additionally increased.

Of the permanent greenhouse gases, the concentration of the most abundant one, carbon dioxide, has been increased by 50% since the beginning of the Industrial Revolution, due to the combustion of fossil fuels. So, just as you are warmed by putting on a heavier coat, so is the Earth. It will take many centuries for that excess CO2 to be removed by natural processes. Therefore, in order to return to normal conditions, we need to figure out how to remove excess CO2 from our atmosphere instead of adding additional man-made CO2 to it by the continued combustion of our unlimited supplies of fossil fuels.

The denier’s inclination to ignore this is not helpful.

Eric Grimsrud

Liberty Lake