Unfortunately, AIDS wasn't discovered until 1981. The graph below shows that the rapid rise in the necessary "driving force" started around 1965. So it couldn't have been AIDS.

[image|http://images.iop.org/objects/physicsweb/news/11/8/2/DrivingForce.jpg|0|Climate Change Driven by Anthropogenic Factors|399|500]

But you get the general point. If you think the driving force for climate change is widgets, all you need to do is have data on widgets for the last 150 years and compare it to the observed temperature. If there's a statistically valid relationship, then there may be reason to investigate that factor further.

The power of this paper is that it shows you don't need to have a detailed understanding of the mechanism/model for the system to see whether a particular factor may be an important driving force or not. You can treat the biosphere as a black box and just look at the inputs and outputs.

For instance, one could compare the rise in temperature with the global population. If a correlation is observed, one could then speculate on why that correlation exists and look at various factors that may contribute.

Cheers,
Scott.