Time of the great freeze

I recall reading this book long ago and thinking it was pretty good.
I wanted to see if it held up so I read it again.
And it doesn't hold up.
There is actually very little plot and the characters were hard to tell apart.
Most of the Earth is under a mile of ice and our heroes are exiled to the surface from New York
because they dared to communicate with people in London.
While traveling across the ice to England, they meet a surprising number of people living on the ice.
They encounter people who have reverted back to early hominid culture, another group who are similar to pre-Columbian Native Americans and some Vikings.
Somehow these people live exclusively on moose and/or walruses (the moose somehow live on algae)
and have fires and wooden ships even though there are no trees on the ice.

Most of these encounters are violent but luckily one of our heroes knows Judo and they have some
kind of combination flame thrower/disintegrator ray.
They travel in solar powered sleighs where they are exposed to the elements, kind of like a
big snowmobile.

All of this sounds silly to me now, but teenage me thought it was a cool adventure.
Young me was also oblivious to the sexism in the book.
A lot of SF books from the 1960s and before and women in only stereotypical roles.
But this book essentially has no women in it.
About the only reference to women is when one of the primitive peoples they encounter is described as ‘screaming like a woman'.

So I was disappointed in the book and can't recommend it.
I have a few others that I am rereading and I hope they hold up better.