Essay On The Last Glacial Maximum

21,000 years ago, the Last Glacial Maximum, or LGM, occurred. It was the most recent period in climate history where ice sheets were at their peak size. This era “represents the nearest of a series of past climatic extremes characterizing the waxing and waning of Quaternary ice ages and as such serves as an excellent testing ground for assessment of sensitivity of the Earth’s climatic system,” (814, MAROGT). Due to this sensitivity of the climatic system, when data modeling global climates it is easier to see the individual effects of various external forcings (factors that alter the climate) when they are manipulated. This makes the Last Glacial Maximum ideal for testing, and it can be essential to global climate data modeling, including our

We manipulated a variety of forcings, predominately greenhouse gas concentrations in the atmosphere and orbital variations of the planet, to determine which contributed the most to causing the Last Glacial Maximum. There are an infinite number of factors at play in the climate system. While it is generally accepted that certain forcings help explain why the Last Glacial Maximum occurred, it is still unclear which factors have a greater effect. We hope to use EdGCM to determine which forcings, whether lower carbon dioxide concentration; lower methane concentration; orbital variations in precession, obliquity, and tilt; or ocean mixing, are most effective in recreating the patterns found in the climatic system during the Last Glacial

The Climate Mapping and Prediction Project, or CLIMAP, was the first interdisciplinary effort to map previous global climates. It resulted in maps displaying the size and location of LGM ice sheets covering 25% of Earth’s land surface, and planet-wide lower surface ocean temperatures, with exceptions in the lower latitudes where some warming may have occurred. While this project was revolutionary for the field, some of its discoveries were met with skepticism. Other climate scientists felt that the mapping of ice sheets was inaccurate in regards to: their extent into relatively low latitudes, presence in certain marine areas, and their overall thickness. Further research proved these errors to be true to certain extents in some regions of the maps. Regardless, CLIMAP was a turning point for interdisciplinary data modeling, and their findings became the cornerstone of the field. In the 1980s, The Cooperative Holocene Mapping Project, or COHMAP, took a step forward from CLIMAP, and aimed to create more accurate mapping of climate ranging from the Last Glacial Maximum to present by drawing from combined data proxies including pollen levels and 14C records. They succeeded, and the accuracy and intricacy of LGM climate modeling has been improving ever since. Current papers, like the Last Glacial Maximum published in Science magazine