Important to remember that IARC just talks about the quality of the evidence, and not the strength of the effect. If they know that something does cause cancer it'll go into group 1, even if it only causes an additional 1 case of cancer per 100,000 population.
So we need other dimensions. Thanks for that article you wrote, made it easy to understand 2b etc.
We need something like the danger of getting cancer from it. Tobacco doesn't make everyone get some kind of cancer, but it hugely increases the risk. What are other cancer dangers in terms of some measurable risk, compare that to this new risk.
Yes, and the rest of this thread shows a few people confused about the meaning of "possibly causes cancer" and how to interpret that wrt their own behaviour.
IARCs comms strategy isn't great, and science journalism isn't great either.
Important to remember that IARC just talks about the quality of the evidence, and not the strength of the effect. If they know that something does cause cancer it'll go into group 1, even if it only causes an additional 1 case of cancer per 100,000 population.
The IARC categories (1, 2a, 2b, 3) aren't that confusing, but they do seem to cause a lot of confusion. Here's a short summary I wrote in another place: https://tildes.net/~food/1774/aspartame_may_be_declared_a_po...