What contributes to atmospheric carbon dioxide?

Answer 1

In the absence of anthropogenic activities, carbon dioxide (CO2) levels in the atmosphere would be fairly static. Animals exhale carbon dioxide, but vegetation converts this back into edible products that are then consumed by those animals. Similarly, rotting vegetation gives off carbon dioxide, but the vegetation is soon replaced by new vegetation that requires the same amount of carbon. The natural cycle contributes no net increase in carbon dioxide concentrations in the atmosphere. Even burning wood or paper has no net effect on atmospheric concentrations of carbon dioxide, although cutting down trees for wood or paper could do so if new trees are not allowed to grown and absorb as much carbon as the trees cut down. So, CO2 concentrations had remained around 260-280 parts per million (ppm) until the time of the Industrial revolution, when the level of CO2 began to rise in line with increasing use of fossil fuels.

The increase from 260-280 ppm to the present 390 ppm of atmospheric carbon dioxide is almost entirely due to human activities. The main cause is by burning fossil fuels such as coal, oil and natural gas. Another important cause is deforestation, mainly as land-clearing for farming.

_______________________________________________________________

There is absolutely zero scientific evidence to make the claim that carbon dioxide has ever been "fairly static". The science behind the levels of carbon dioxide differ vastly from the political viewpoint stated.

CO2 has varied by about 800 years behind temperature. This is a well known trend for the past 650K years according to all available data. The current upward trend started well over 10,000 years ago, shortly after the temperatures started to rise. Carbon dioxide has always followed temperature. With the current warming trend now at over 10 degrees C, it is a normal and expected occurrence that CO2 levels would eventually follow. Levels as low as 190 ppm have been observed in the past 10,000 years, as well as levels (reported by Noble winning science experts from the 1800's) of well over 400 ppm. (Beck 2008). The overall trend for CO2 has been upward almost non stop for the past 9,300 years. There have been fluctuations, but this is the undisputed trend.

Man's production of less than 6% of all CO2 is possibly a partial contributor to the current levels of CO2. That is a very possible scenario. Nature's production of 94% is a known cause of increase. To blame man as the sole reason for increase though is misleading and absolutely false. We know that the levels of CO2 rose over 100 ppm prior to man starting to use any coal.

The one undisputed fact of CO2 increase is the know relationship between temperature and the levels of CO2 in our atmosphere. Temperature causes CO2 to rise. This is a known event. Human additions are a speculative (albeit possible) issue.