Weather.

[Sekwo]

90% mortality rate is the average in any kind of major event risk calculation, the real death rate would probably be much higher as modern life has lost most of its connection to land and the growing of food, in the UK it has been said be are 4 generations removed from the land, a generation is usually taken as about 30 years.
most people are so reliant on modern food deliveries they would perish within a short time frame if ever these deliveries stopped.
government perception of risk is only about which party will win the next election.

I wouldn't argue with the figure. I've literally drawn that figure out of the air, and it's my "order of magnitude" guess much farming land would still grow food. Basically, it looks like the interiors of most big land masses become arid deserts. That must mean all the wind and weather patterns change, so even areas outside the interiors, that are lush farming land now, may have their farming wiped out.

The only real evidence we have that not everywhere becomes uninhabitable, is that plenty of species do make it through the ice-ages. So somewhere, there's got to be inhabitable areas.

It is bizarre that the highest figure I saw for a death from covid was about 2% (before they started realising that many more people were being infected with a benign form, so it was really about 0.1%). And it was something like 0.01% or lower for young adults, yet, the likely probability of dying from the next ice-age is about 5% ... and people totally ignore it.