He appears to have spent more time on ice fields above 18,000 feet than any human being in history. (dotearth.blogs.nytimes.com)
Temperature varied rapidly in the climb out of the last glacial period — as a result of ice fields changes — and peaked around 6,000 years ago. (watertechbyrie.com)
The process is self reinforcing and runaway ice growth ultimately covers much of the north in kilometres deep ice fields. (watertechbyrie.com)