The Sixth Winter

Frank Rhind was lucky. He saw the Ice Dancer and lived. The town of Hays died. And still they didn't believe Dr. William Stovin's warnings. For very many years climatologists had been predicting a change in the world's climate but they always believed that the process would take centuries. Now there was a reason to believe differently. Stovin had staked his career and credibility on trying to persuade the U.
S. National Science Council to act, but 15, 000 years of warmth had lulled mankind into thinking that climatic history was over. Already it was too late. The new Ice Age had begun. One by one the great northern cities - Chicago, Oslo, Montreal, Moscow, Leningrad - came under siege. Some fell and were evacuated, sending their young, old and sick to crowded areas further south. Crops and animals were destroyed.
Governments drew lines of catastrophe across their national maps. Doomsday prophets were in full cry. Technological man was overwhelmed. The world had changed. Some time in the year future the next Ice Age will be triggered off. It could happen in a thousand years' time, or in a century from now. Or it could, quite literally, happen next winter. This book is fiction only because the events described have not yet happened.
But it is not science fiction because all the science in the book is fact. When the year arrives that we see the sixth winter resembling 1792 within the space of a decade or so, then the Ice Age will be with us in a matter of weeks - and it will develop very much as described here.