"Marijuana has higher levels of THC, therefore its more dangerous"

This is a statement that is both right and wrong. It is right in the sense that marijuana does have higher levels in THC today then it did in the 1960's. A small number of low-THC samples seized by the Drug Enforcement Administration are used to calculate a dramatic increase in potency. However, these samples were not representative of the marijuana generally available to users during this era. If you where to take a look at potency data from the 1980's to present day you will notice that they show no increase in average THC content.

Even if this statement was completely true and there was a significant and constant increase in THC levels between 1960 and now, It still wouldn't necessarily mean that its more dangerous. In fact, it is virtually impossible to overdose on THC from smoking marijuana. Scientist have come to the conclusion that the ratio of how much marijuana you would need to get intoxicated relative to the amount needed to kill them 1 to 40,000. In simpler terms, for you to overdose from marijuana use, you would have to consume 40,000 times as much marijuana needed to get you stoned. This scenario is highly improbable.