18/09/2020
There is no question that man-made global warming is occurring. You can be sure of this because there are two incontrovertible facts about global warming shown by direct scientific observations. These measurements are not in doubt and rely on basic settled science.
Observation 1: The atmosphere's excess CO2 is human generated
The proof for this comes from basic chemistry. There are two common isotopes of carbon found in nature, carbon-12 and carbon-14.
"Living things, like animals and trees, are in equilibrium with the atmosphere. As they eat and breathe and interact, they contain the same proportions of carbon isotopes as the atmosphere. When they die, that carbon-14 decays over a long time, and since the organism is no longer eating and breathing, no new carbon-14 comes in, and eventually the only carbon remaining is carbon-12 (and some carbon-13). Fossil fuels like oil and natural gas come from plants that died millions of years ago and have no carbon-14 left. The CO2 produced by burning fossil fuels contains only carbon-12" (Dunning).
Each year, scientists directly measure that about 15 billion tons of extra carbon-12 are added to the atmosphere. The only possible source for this is burning fossil fuels.
Observation 2: The human-generated CO2 is warming the planet
The proof for this comes from spectroscopy, a 200-year-old scientific technique. "Spectroscopy is a method of detecting elements by looking at how electromagnetic radiation passes through them. Different elements have electrons in orbits at varying energy levels, and this affects the way they resonate...."
"The Earth's surface is warmed by the sun, and as a warm globe in space, the Earth itself emits that same heat right back out, as infrared radiation. If we go outside and point a spectrometer at the sky, we can see there are peaks and valleys in the infrared spectrum. Some wavelengths of heat fly right out into space unhindered, while other wavelengths are absorbed by the atmosphere, and that heat stays there, where we're able to detect its wavelength with our spectrometer" (Dunning).
This next part is complicated but fascinating: The basic shape of the infrared (heat) spectrum is defined by water v***r. "Most of the infrared radiation that escapes the Earth goes through a window left open by water v***r, which we call the infrared window. This window in the spectrum, which is pretty wide, is centered around a wavelength of about 10 µm (microns). At higher and lower wavelengths, water v***r absorbs much of the Earth's radiated heat, so the Earth has always relied on this open window in the spectrum to allow the excess heat to escape. One end of the infrared window is overlapped by CO2's absorption range, which is centered around 15 µm. The amount of CO2 in the atmosphere acts like a sliding door which widens or narrows the infrared window. As CO2 increases, the infrared window is narrowed, less radiation escapes into space, and more heat is absorbed by the atmosphere. At the other end of the infrared window, around 7.5 µm, methane has a similar effect, contributing about 1/4 as much warming as CO2" (Dunning).
The Earth's infrared spectrum has been continuously measured from space by satellites since 1970. The measurements paint a clear picture that the infrared window is narrowing in the 15 µm range of CO2, i.e. that more heat is being trapped by the Earth's atmosphere every year, thus proving that the increased man-made CO2 is causing global warming.
Dunning, B. "The Simple Proof of Man-Made Global Warming." Skeptoid Podcast. Skeptoid Media, 13 Dec 2016. Web. 18 Sep 2020.
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