Many of you probably watched the finals of golf’s U.S. Open from Erin Hills, Wis., recently. This beautiful golf course was naturally carved during the retreat of the Wisconsin ice field some 15,000 years ago … the end of the latest ice age.
How often do ice ages occur? According to the Christian Science Monitor, August 7, 2013, “For the last 900,000 years, mile-thick ice sheets have waxed and waned in the Northern Hemisphere with remarkable regularity — building over periods of about 100,000 years and retreating in the space of only a few thousand years, only to repeat the cycle.”
Manmade? Hardly. The first human didn’t arrive in North America until 15,000 years ago.
What causes these cycles? The Christian Science Monitor states, “according to a team of scientists from Japan, the U.S., and Switzerland...changes to the shape of Earth's orbit over time, as well as long-term changes in the orientation of its axis, and their impact on solar radiation at high northern latitudes were the most significant astronomical influences.”
How about CO2? The Christian Science Monitor continues, “The team also weighed the relative contributions of changes in atmospheric concentrations of carbon dioxide, a greenhouse gas, to the 100,000-year glacial cycles. While carbon dioxide decreased as the ice sheet expanded and cooled the climate and increased again as the climate warmed, CO2 levels did not determine the overall sequence of events during each 100,000-year cycle.”
Just to keep you thinking … if you’re curious.