Levels of global catastrophes: from mild to extinction
It is important to make a bridge between existential risks and other possible risks. If we say that existential risks are infinitely more important than other risks, we put them out of scope of policymakers (as they can’t work with infinities). We could reach them if we show x-risks as extreme cases of smaller risks. It could be done for most risks (with AI and accelerator's catastrophes are notable exceptions).
Smaller catastrophes play complex role in estimating probability of x-risks. A chain of smaller catastrophes may result in extinction, but one small catastrophe could postpone bigger risks (but it is not good solution). The following table presents different levels of global catastrophes depending of their size. Numbers are mostly arbitrary and are more like placeholders for future updates.
http://immortality-roadmap.com/degradlev.pdf
That article says:
That would be really bad but it's not the same as total extinction.
I don't think that's the timeframe of the LW community as shown by our census.
timeframe (2030)
I checked the timeframe in Arctic-news.com. They said that things will become serious after 2030, but extinction will happen around 2060. It is shown on last graph in http://arctic-news.blogspot.ru/p/the-mechanism.html As I remember the LW census, it put AI on 2060? Could you remind me exact data?