Observations Show that the Increase of Carbon Dioxide is Fully Caused by Human Activities.

There are two independent lines of evidence showing that the observed increase in atmospheric carbon dioxide is 100% due to human activities. The first is mass balance. The observed increases in the atmosphere and oceans add up, within uncertainty, to the total amount emitted from the burning of fossil fuels. The second line of evidence rests on observed changes in isotopic ratios of carbon dioxide. Interannual variations of the global atmospheric growth rate can be shown to depend largely on variations in temperature and precipitation. Removal of the variance caused by the latter factors clearly brings out the acceleration of the growth rate in recent years, which is almost certainly caused by the acceleration of the global emissions. Trends of the observed atmospheric spatial pattern do not contradict the above assertions.