You don't need a degree to have some common sense. Is your google broken. This is from your own employer...
"In addition to multi-millennial glacial and interglacial cycles, there are shorter cold-warm cycles that occur on approximately 200 to 1,500 year time scales."
Effective beginning 5/27/2025: This website, and all linked websites under the control of the agency is under review and content may change.The Climate Change Resource Center (CCRC) connects land managers and decision makers with useable science to address climate change in natural resources...
www.fs.usda.gov