"The Carbon Cycle: A Hallmark of Global Environmental Change "
Today, the abundance of CO2 in the atmosphere is at the highest it has been in the past twenty million years. The current concentration in CO2 in the atmosphere (375 ppmv) has increased by more than 30% since the pre-industrial era 250 years ago and has doubled its value (180 ppmv) during the glacial epochs. The current high levels of CO2 and other trace constituents in the atmosphere are already a significant change in a fundamental forcing on the Earth’s climate system. This change is continuing.
The contemporary increase in CO2 is intimately tied to the exploitation of natural resources for human energy consumption. The recent increase in CO2 is caused primarily by the combustion of fossil fuels and secondarily by land cover change.
The dynamics of the global carbon cycle pose interesting
and important scientific and policy issues. This paper is a reflection
on the author’s work over the past 25 years on this topic. There have been
some successes; there have been many failures. It is hopefully worthwhile
to consider both.