ABSTRACT
Climatic changes during the last five or six thousand years appear, at some times, to have allowed sufficient vegetation for primitive men and animals to travel across what are now deserts in north Africa, central Asia and northern Mexico-south-western United States of America, and, at other times, to have cut off these routes of trade and migration. Within the last thousand years various categories of evidence suggest that there was, at first, rather little permanent ice on the Arctic seas and, later, such a great extension of this ice that grain growing was for centuries impossible in Iceland and the total evacuation of that country was considered; at the same time, the cod fishery almost disappeared even from the Faroe Islands. In the worst decades Scotland, as well as parts of Scandinavia and Iceland, experienced famine; upland farms and villages in England and Germany may have been abandoned partly for this reason.
