The Fruits of Civilization (67-3) Global Warming continued


Despite the gloom and doom espoused by scientists and even a few political leaders, there has been no urgency in addressing climate change. International agreements have been nothing more than gauzy ambitions.

Part of the reason for inaction is that in many places, warmer weather has been welcomed. Storms are spotty enough to not have caused sufficient consternation for alarmed determination to set in. It is as if a long fuse to a bomb has been lit, but instead of inciting dread, folks are enjoying the sparkler effect as the wick burns down.

The warnings about global warming have been extremely clear for a long time. We are facing a global climate crisis. It is deepening. We are entering a period of consequences. ~ Al Gore in 2005

Earth is habitable for animals because of its orbital proximity to the Sun, and because of the natural clemency that the atmosphere and oceans confer on surface temperature. Water vapor and a mixture of gases keep the planet at least 33 ºC warmer than it would be without its blanket of air.

Earth’s atmosphere reflects 30% of the Sun’s rays that it receives and absorbs another 30%. The remaining 40% drenches the surface in warmth and light.

Warmed surfaces send most of the heat back into the atmosphere, chiefly via infrared radiation, ascendant warm air, and evaporated water.

Greenhouse gases, such as carbon dioxide, absorb and emit heat via infrared radiation. When such radiation from Earth’s surface hits a molecule in the atmosphere, the molecule absorbs the heat energy and emits it later.

Toasted gas molecules fire infrared energy in a random direction. Sometimes the emitted heat heads into space. Other times the warmth spreads toward the surface, creating a greenhouse effect.

The atmospheric concentration of greenhouse gases embodies a balance between emission sources and sinks which absorb heat. Oceans, forests, and soils serve as Earth’s carbon sinks. But it is the fossil fuel deposits so prized by man that are the greatest global sink of carbon. Our self-destruction largely owes to burning the carbon which kept the planet habitable because it was deposited.

The legacy of our fossil fuel burning today could last for tens of thousands of years, if not hundreds of thousands of years to come. ~ American oceanographer Richard Zeebe

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Air in the human era has been nominally 78.09% nitrogen (N2), 20.95% oxygen (O2), 0.93% argon (Ar), and 0.04% carbon dioxide (CO2), with trace amounts of other gases.

Nitrogen, oxygen, and argon are not greenhouse gases, as they form monatomic molecules which are not rattled when jostled. Being energetically unaffected by infrared radiation means they generate no greenhouse effect.

Water vapor (H2O) continues to have the greatest greenhouse effect. The water cycle has played an enormous role in making and keeping Earth habitable.

There is a positive feedback loop among greenhouse gases and water vapor that generates a warming gyre. By trapping extra heat, greenhouse gases affect the amount of water vapor in the air. Heating the air by adding CO2 means the air takes up more water vapor, which further warms the atmosphere. Thus, greenhouse gases engender a multiplier to their warming effect.

In this century, as more attention has been paid, assessments of greenhouse gas emissions have regularly been revised upwards. The emissive impact of human activity has been underestimated, which means the situation is direr than commonly reported.