The upper image shows the carbon dioxide concentration in the atmosphere over the last 250 years based on both direct atmospheric measurements and sampling of gases trapped in ice cores.
The bottom image shows the rate of change of the abundance of carbon dioxide in the atmosphere expressed as 1012 kg carbon per year (also known as gigatonnes carbon (GtC) per year). A comparison is shown between the "Total Flux" needed to explain the observed changes in atmospheric carbon dioxide content and the estimated flux of carbon generated from fossil fuel burning (Marland et al. 2003). Since ~1900, the flux of carbon entering the atmosphere from fossil fuel consumption has exceeded the net flux of carbon from all sources, indicated that the sum of all other impacts on the carbon cycle has been acting as a net sink, and serving to sequester some of the carbon being released from fossil fuel consumption. Dissolving into the oceans and increases in biological productivity are likely sinks for removing some of the contributed carbon dioxide.
The net flux of carbon into the atmosphere before the rise of fossil fuel burning may be a natural fluctuation or it may also be related to human activities such as the clearing of forests or changes agriculture during the first industrial revolution. As seen at right, the modest changes from ~1750-1850 are largely within the margin of natural variability, but the subsequent accummulation of carbon dioxide far exceeds any concentration witnessed in the last 400,000 years and may have not occurred over the last tens of millions of years.
Click on a date/time to view the file as it appeared at that time.
|current||01:28, April 20, 2007||481 × 599 (75 KB)||Eric Wester||The upper image shows the carbon dioxide concentration in the atmosphere over the last 250 years based on both direct atmospheric measurements and sampling of gases trapped in ice cores. The bottom image shows the rate of change of the abundance of carbo|