Natural climate change

Earth began with a 2.2 billion-year warm cycle followed by a 300 million year cool cycle.

Earth’s shortest warm cycle lasted 365 years—950-1315 AD. Earth’s shortest cool cycle lasted 370 years—530-900 AD.

Populations near oceans fear rising sea levels. Sea level today is about seven feet lower than during the Minoan warm cycle 3,500 years ago. A look into the Medieval Warm cycle—950-1315 sheds light on climate to expect.

Brian Fagan’s book The Great Warming © 2008 offers insight into years 950-1315, Earth’s last warm cycle. Fagan wrote 15 Fagan books about climate change. He presents both cycles of climate change. He believes human activity adds to global warming.

Comparing current high temperatures with the last warm cycle is logical. Unfortunately, there are no temperature records of the last warm cycle—950-1315. Daniel Fahrenheit’s thermometer was not invented until 1724.

World temperature records became available in about 1850 during the Little Ice Age (LIA). Record high temperatures reflect the LIA and our current warm cycle.

Ice core data for Earth’s last 10,000 years identifies warming for 4,000 followed by cooling the past 6,000 years. Computer modeling based on data from inhabited areas suggest ice core data may not be reliable.

History of Earth’s last seven warming and cooling cycles might help inform us of what our current cycle might bring.

The Milankovitch Theory—check the Internet—predicts warmer than usual winters and cooler than usual summers in the Northern Hemisphere.

Bob Launhardt,

Pinehurst