Tuesday, November 6, 2012

How Does Carbon Dioxide Cause Global Warming?

The most significant property of Carbon Dioxide, from a human point of view, is its ability to trap heat in the atmosphere that would otherwise be lost to space.

Why does this happen?

Heat energy is energy with a longer wavelength than visible light. Carbon Dioxide (CO2) absorbs this type of energy whereas the other major atmospheric gases Nitrogen (N2) and Oxygen (O2) do not do this.

When a molecule of Carbon dioxide is exposed to long wavelength energy which we commonly call heat, it absorbs this energy and its speed increases. This added speed is an above-normal energy state, meaning it is hotter than it would normally be. Eventually this molecule will lose, or radiate this heat again and return to its normal state.

That energy is released in the same form, as heat. Also, it is given off equally in all directions. The important point here is that a fair portion of that released heat is emitted back towards the earth.

What is the Problem?

The heat that the CO2 absorbs initially is mostly energy that is being reflected off the surface of the earth back out into space. By absorbing and then radiating the energy, Carbon Dioxide effectively redirects some of that energy that would otherwise be lost back down to the surface. This is effectively a heat blanket, which is why it's referred to as a "greenhouse" effect. Increasing the amount of CO2 in the atmosphere therefore increases the surface temperature.

Even a slight rise in surface temperature can have significant effects. A warmer surface temperature means a warmer ocean surface. This leads to more evaporation which not only changes weather patterns but also increases the heating effect since water vapor behaves the same way as Carbon Dioxide.

This significant property of Carbon Dioxide is the main reason it's seen as a negative aspect of energy production and why we need to seek methods of energy production that do not involve releasing more CO2.

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