The last Ice Age, also known as the Last Glacial Maximum (LGM), began approximately 26,000 years ago and ended around 11,700 years ago. It was a period of extensive glaciation, with large ice sheets covering much of North America, northern Europe, and Asia. The exact causes of the onset and termination of the last Ice Age are still debated among scientists, but multiple factors are believed to have played a role.
The onset of the last Ice Age is thought to have been triggered by a combination of changes in Earth’s orbital parameters (known as Milankovitch cycles), which affect the amount and distribution of solar energy reaching the planet, and feedback mechanisms involving ice-albedo feedback (whereby the reflection of sunlight by ice and snow leads to cooling and further ice growth) and changes in atmospheric greenhouse gas concentrations. These factors caused a gradual cooling of the climate over thousands of years, leading to the growth of large ice sheets.
The termination of the last Ice Age is thought to have been primarily driven by changes in greenhouse gas concentrations, particularly carbon dioxide (CO2), in the atmosphere. As the climate cooled during the Ice Age, large amounts of water were locked up in ice sheets, causing a drop in sea level and exposing land that was previously submerged. This resulted in changes to ocean circulation patterns and increased carbon uptake by the oceans, which in turn led to a decrease in atmospheric CO2 levels. Eventually, a threshold was crossed, and rising greenhouse gas concentrations, along with other factors, initiated a warming trend that led to the melting of the ice sheets and the end of the Ice Age.
It’s important to note that the onset and termination of an Ice Age is a complex interplay of various factors, and the exact mechanisms and timing are still the subject of ongoing research and scientific investigation.
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