Burning of Fossil Fuels

by Alex Smith

When you burn fossil fuels it creates greenhouse gases, which as you know, trap the heat the sun gives off on earth. Thus global warming :)

Barry's Response - That's the basic forumla, Alex. The original.

The whole thing works off of capture and feedback. Let's start with a condition I'll call Equilibrium 1. It could represent the current state of affairs. At this point, incoming solar radiation (insolation for short) reaches the earth. Some makes it to the ground; some is reflected off the clouds and oceans; some is absorbed by the atmosphere and oceans. Of the part not reflected (and kept) we receive the benefit of that warmth and energy...plants grow water evaporates to deposit rain on dry land.

However we'd boil up pretty soon if none of that ever left. So it does. By exiting longwave radiation. Some of that makes it out of the earth/atmosphere system; some is reflected back down by clouds; some is absorbed by the atmosphere (greenhouse effect).

It's starting to get complicated. Especially if you wanted to track these energy flows using a calculator. The point is after many iterations and corrections, balance is achieved, approximately. That's what we mean by equilibrium, and the temperature does not change much day-to-day or year-over-year even.

What happens if something upsets that balance? If, say, a greater portion of that exiting radiation is consistently absorbed by the atmosphere, we'd have an increase in the greenhouse effect we've heard so much about lately. Now we will automatically shift to a new balance...one where a higher surface temperature (i.e., global warming) is needed to give a greater amount of longwave radiation leaving in the first place to compensate for the increased absorption and still have incoming energy roughly equal to departing energy. Then we have Equilibrium 2.

In reality, there is a new equilibrium every second or less, but the changes would be so tiny they are not worth dealing with individually. Instead we concern ourselves with long term trends. That's why changes in the greenhouse effect have us concerned. You can probably imagine how oversimplified this story is but it helps us get the point.


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