There is an idea circulating the internet that tries to explain away climate change because it violates the laws of thermodynamics. A flimsy argument at best which tries to explain that the long-wave radiation emitted from the surface of the earth and trapped by greenhouse gases can not heat the planet. There are some fantastic examples offered like an ice cube can not boil water or a lamp will not get hotter when its own light is reflected back at it from a wall.
Both are correct, however neither disproves climate change in any way shape or form. This of course is because the proponents of this idea totally fail to address the driver of heat on our planet, the sun.
The Sun Matters
The sun emits light energy (heat) which falls upon the Earth, the light reaching the earth does so in the short-wave. Short-wave radiation is either absorbed or reflected by the surface of the earth based on Albedo. Snow covered sea ice can have an Albedo as high as 0.9, reflecting 90% of the short-wave radiation from the sun, while the open ocean has an Albedo of 0.06 and absorbs 94% of the Sun’s short-wave radiation. The short-wave radiation absorbed by the planet causes heating, the sun heats the planet.
The vast majority of solar radiation reaching the planet is lost to space while only a small amount comparatively is trapped by the Earth’s atmosphere. The heat trapped by the atmosphere is long-wave radiation that is the heat energy that has been absorbed by the planet. However, not all the long-wave radiation is trapped by greenhouse gases in the atmosphere, long-wave radiation also escapes into space. As the concentration of greenhouse gases increases in the atmosphere so in turn does the amount of long-wave radiation trapped in the atmosphere increase. Yet at no time is the amount of heat trapped by the atmosphere greater than the amount of heat delivered by the sun and lost to space.
This is why the theory of climate change does not violate the laws of thermodynamics. The Earth is not heating the atmosphere, the sun is. The heat from the sun warms the surface of the planet and some of the radiated heat from the surface of the Earth is captured by greenhouse gases. The more greenhouse gases in the atmosphere, the more heat that is trapped.
Take the sun out of the system and the planet freezes, take all the greenhouse gases out of the system and the planet would be extremely cold. Conversely, add more greenhouse gases to the atmosphere, as we are doing, and the temperature on the planet increases over time.
The problem with these types of arguments is that they can create doubt where there should be none. If one does not take the time to do some research into thermodynamics in order to understand the basic argument then it can be difficult to see the fallacy in the reasoning.
The lamp not getting hotter when its own light is reflected back at it from a wall is a perfect example of how these nonsensical arguments can cause distraction. We all know a light-bulb will not get warmer in this way, however this in itself proves nothing in relation to climate change. The heat source driving climate change is the sun, thus the lamp must represent the sun, nobody is saying the sun is getting warmer. The sun (lamp) is warming the Earth (wall) and the warmed Earth (wall) is radiating heat which is being trapped by greenhouse gases.Related posts: