Laura Elder is worried about global warming ("Sea level rise must be part of the conversation," The Daily News, Oct. 30). This warming is part of a natural cycle.
A galactic year is the time it takes the solar system to orbit the center of the Milky Way. This is between 240 million and 300 million years. It's divided into two large cycles. For 90 percent of the time the Earth is so warm that ice can only be found in the mountains and not at sea level. The other 10 percent is the ice age. We're living in an ice age now.
There are two natural cycles in the ice age: glacial and interglacial. We're in the interglacial. The interglacial has two large cycles and two cycles within a cycle. The little ice age lasted from about 1400 to 1800. A warming cycle started in 1000 and one started in 1800. There is also a 40-year cycle alternating between cooling and warming.
Native Americans that lived in the southwest (1,000 years ago) had cycles of wet (cooling) and dry (warming) of 40 years each. In 1973, it snowed enough that many thought we were going to have a new glacial period, but a warming started in 1980. A new cycle of global cooling will begin in 2020 and last to 2060. These cycles are natural, not man-made.
Editor's note: Just as a matter of fact, the editorial at issue never mentioned global warming.