During the ice age, so much of the world's water was locked up in continental glaciers
that the height of the oceans dropped by 120 meters.
Today, geologists know these rocks as glacial erratics, stones transported many thousands of miles to their current resting place by the great continental glaciers
that once covered the land.
The combination of alpine and continental glaciers
through the Pleistocene pushed tundra and boreal forests far down into what is now the United States.
The geological history of glaciation has been a subject of lively debate ever since Swiss naturalist and geologist Louis Agassiz (1807-1873) convinced the scientific public that his idea of vast continental glaciers
Ocean glaciers, affected by wet airflow from the oceans, would shrink by 52.5 percent, and Asian continental glaciers
, formed in the continental climate would shrink by 24.4 percent.
According to theory, a greenhouse warming could raise sea levels by melting continental glaciers
and ice caps and by thermally expanding the oceans.