Fossil fuels such as gasoline, methane and propane contain mostly carbon. When these fuels are burned, they react with oxygen and produce carbon dioxide.
Because of our heavy use of fossil fuels, the amount of carbon dioxide in the atmosphere has been increasing since the industrial revolution. The destruction of forests which use carbon dioxide also contributes to the increase in carbon dioxide.
Most of the light energy from the sun is emitted in wavelengths shorter than 4,000 nanometers (.000004 meters). The heat energy released from the earth, however, is released in wavelengths longer than 4,000 nanometers. Carbon dioxide doesn't absorb the energy from the sun, but it does absorb some of the heat energy released from the earth. When a molecule of carbon dioxide absorbs heat energy, it goes into an excited unstable state. It can become stable again by releasing the energy it absorbed. Some of the released energy will go back to the earth and some will go out into space.
So in effect, carbon dioxide lets the light energy in, but doesn't let all of the heat energy out, similar to a greenhouse.
Currently, the amount of carbon dioxide in the atmosphere is increasing at the rate of about one part per million per year. If this continues, some meteorologists expect that the average temperature of the earth will increase by about 2.5 degrees Celsius. This doesn't sound like much, but it could be enough to cause glaciers to melt, which would cause coastal flooding.
LOL
Other meteorologists disagree.
Drank the entire pitcher of Kool-Aid, didn't you?
To put it more simply, the natural rise in CO2 from the natural warming of the oceans by 1C or so would have resulted in 5-10 ppm rise of CO2 in the atmosphere from outgassing Instead we we have seen 110 or 120 ppm rise so far.
central_va, when you say "some meteorologists expect that the average temperature of the earth will increase by about 2.5 degrees Celsius. This doesn't sound like much, but it could be enough to cause glaciers to melt, which would cause coastal flooding." you are leaving out a lot of information.
The phrase "some meteorologists" is true enough, but it's a small number. The people who mainly push catastrophic warming are not meteorologists but climate modelers who know very little about weather. It's mostly not in the models. For example the strong storms that are a claimed result of manmade "climate change" are a negative feedback. Therefore the 1C or so warming from CO2 itself would be diminished by weather feedback. But the models don't predict stronger storms (on average) which is about the only way your 2-3C claim can come true.
More importantly the temperature rise in the last 10-20 years is more like 0.05C per decade so there is almost no chance of the a 2C (or more) rise in 100 years as is claimed by alarmists. Even more importantly, as most meteorologists know, the weather drives the global climate. Thus water vapor cannot properly be viewed as a feedback but as the controller of equilibrium temperature. Very briefly, if water vapor is spread out evenly there will be more warming. If water vapor in bunched up, then there will be cooling. All the "extreme" weather being claimed as manmade is actually a result of natural patterns. For example droughts start and stop naturally. The high temperatures in the drought may be a teeny bit higher thanks to added CO2, but that doesn't affect the global temperature more than trivially. As another example, heavier rains are another "extreme" weather claim. but that just increases the water cycle and negative feedback.