SkS Analogy 2 - Ferrari Without Gas

Tag Line

A Ferrari without gasoline goes nowhere.
Greenhouse gases (GHGs) without infrared (IR) radiation cause no warming.

Elevator Statement

• The concentration of GHGs is like the size of a car engine: higher greenhouse gas concentration is like a bigger engine. IR radiation is like the gasoline in the tank of a car.
• Just as gasoline is the fuel that drives an engine, infrared radiation is the fuel that drives the greenhouse effect.

Climate Science

Global warming occurs because IR radiation emitted from the surface of the Earth is captured by GHGs in the atmosphere, increasing the temperature of the atmosphere and of the Earth. Increased GHGs in an atmosphere with constant background IR radiation will absorb an increasing fraction of the emitted IR radiation, causing warming. Increased GHGs in the atmosphere combined with increased IR radiation causes even faster warming. Warming melts snow and ice, replacing it with dark oceans that absorb Ultraviolet (UV) radiation instead of reflecting it back out to space, causing more warming. The warming oceans emit IR radiation. The combination of the sun warming oceans that were once covered in ice, combined with increased emissions of IR radiation from the warm oceans, is causing the Arctic to warm faster than anywhere else on Earth.

Snowball Earth is a period about 650 million years ago when CO₂ concentrations were much higher than today, but when the entire Earth was covered in ice. Some people claim that the existence of an ice age when CO₂ concentrations were higher than today proves that CO₂ does not cause warming. Part of what allowed Snowball Earth to occur was because solar radiation was about 4% lower than today. But a major reason that Snowball Earth persisted for so long is that snow and ice reflect 90% of incoming solar radiation, reducing the generation of IR radiation to the point that the greenhouse effect was severely reduced. Even with high concentrations of CO₂, without IR radiation the greenhouse effect was much weaker than it is today, and the ice persisted.

To power a Ferrari, one needs a big engine and plenty of gasoline. To power the greenhouse effect, one needs lots of GHGs and IR radiation.

Additional Reading

For additional reading see a study published in Nature Communications and summarized in this SkS posting.

Posted by Evan on Monday, 24 April, 2017

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