From 40,000 to 30,000 years ago, humans entered the tundra-like
environments of ice age Ukraine, Russia, and Siberia. Plant life was less
abundant here, so they had to learn to hunt large mammals such as mammoth,
to tailor well-¿ tting skin clothing, and to manage ¿ re. Sites from this era
suggest how they lived. At Pushkari, in Ukraine, 19,000 years ago, where
temperatures could fall to í30°C in winter, people lived in round houses built
using mammoth bones. Though humans may have entered North America
earlier, we know they crossed there from eastern Siberia by about 13,000
years ago.
By 13,000 years ago, the range of our species was already much wider than
that of any other large mammal species, a clear sign that our remarkable
ecological and technological prowess was already apparent in the Paleolithic
era. These dates also suggest that the pace of innovation accelerated during
the last 50,000 years. This is the archaeological reality behind the idea of an
“Upper Paleolithic Revolution.”
As humans migrated, their numbers increased, and so did the number of
archaeological remains they left behind. Though estimates of Paleolithic
populations are largely guesswork, Italian demographer Massimo Livi-
Bacci suggests there were several hundred thousand humans 30,000 years
ago and 5 or 6 million humans at the end of the Paleolithic era, about
10,000 years ago.
The dominant form of change in the Paleolithic era can be described
using the ugly word “extensi¿ cation” (as opposed to “intensi¿ cation”). By
“extensi¿ cation,” I mean technological change that allowed migration to
new environments without permitting more intensive exploitation of existing
territories. Extensi¿ cation explains why the size and complexity of individual
human communities did not increase during the Paleolithic era, though the
total number of communities did increase.
As Paleolithic humans explored more environments and developed new
techniques to deal with them, they began to have an increasing impact on
their environments. Here are two striking examples. Humans transformed
the environments of entire continents by systematically ¿ ring the land.
Australian archaeologist Rhys Jones (1941–2001) coined the phrase