Interesting discussion of CO2 levels

At Climate Audit here.

Excerpt:

Leif Svalgard writes:

In 2006 less CO2 was added to the atmosphere than in 1983. In 1980 more CO2 was added to the atmosphere than in 2004. Why is that? I’m sure that the world’s human population has increased its output of CO2 significantly since the 1980s. Where did it go? Why does the growth rate change from year to year? Biology? Algae in the sea? I don’t know, just asking. And why does nobody else ask this?