Last Glacial Maximum
The Last Glacial Maximum (LGM) was the most recent time during the
The LGM is referred to in Britain as the Dimlington Stadial, dated by Nick Ashton to between 31 and 16 ka.[
The LGM was followed by the
According to Blue Marble 3000 (a video by the Zurich University of Applied Sciences), the average global temperature around 19,000 BC (about 21,000 years ago) was 9.0 °C (48.2 °F). This is about 6.0 °C (10.8°F) colder than the 2013-2017 average.
The figures given by the Intergovernmental Panel On Climate Change (IPCC) estimate a slightly lower global temperature than the figures given by the Zurich University of Applied Sciences. However, these figures aren’t exact figures and are open more to interpretation. According to the IPCC, average global temperatures increased by 5.5 ± 1.5 °C (9.9 ± 2.7 °F) since the last glacial maximum, and the rate of warming was about 10 times slower than that of the 20th Century. It appears that they are defining the present as sometime in the 19th Century for this case, but they don’t specify exact years, or give a temperature for the present.
Berkeley Earth puts out a list of average global temperatures by year. If you average all of the years from 1850 to 1899, the average temperature comes out to 13.8 °C (56.9°F). When subtracting 5.5 ± 1.5 °C (9.9 ± 2.7 °F) from the 1850-1899 average, the average temperature for the last glacial maximum comes out to 8.3 ± 1.5 °C (47.0 ± 2.7 °F). This is about 6.7 ± 1.5 °C (12.1 ± 2.7 °F) colder than the 2013-2017 average. This figure is open to interpretation because the IPCC does not specify 1850-1899 as being the present, or give any exact set of years as being the present. It also does not state whether or not they agree with the figures given by Berkeley Earth.
According to the United States Geological Survey (USGS), permanent summer ice covered about 8% of Earth's surface and 25% of the land area during the last glacial maximum. The USGS also states that sea level was about 125 meters (410 feet) lower than in present times (2012).
When comparing to the present, the average global temperature was 15.0 °C (58.9 °F) for the 2013-2017 period. Currently (as of 2012), about 3.1% of Earth's surface and 10.7% of the land area is covered in year-round ice.
The formation of an ice sheet or
These anticyclones generated
All over the world, climates at the Last Glacial Maximum were cooler and almost everywhere drier. In extreme cases, such as
Most of the world's deserts expanded. Exceptions were in what is now the
In the period before the Last Glacial Maximum, many areas that became completely barren desert were wetter than they are today, notably in southern Australia, where