Short answers, pulled from the story.
The period known as the Last Glacial Maximum occurred between 26,000 and 20,000 years ago. Scientists use terrestrial cosmogenic nuclides to date the position of these ancient ice margins. Radiocarbon dating provides another method for establishing the timeline of glacial growth.
Permanent summer ice covered about eight percent of Earth's surface during this time. Land area coverage reached twenty-five percent under these frozen conditions. Massive sheets of ice locked away water exposing continental shelves and joining land masses together.
The average global temperature about 21,000 years ago was approximately six degrees Celsius colder than today. Sea surface temperatures in the western subtropical gyre of the North Atlantic were around five degrees Celsius colder compared to today. All over the world climates were cooler and almost everywhere drier during this period.
Ice sheets in Europe produced extensive anticyclones that generated dry air masses reaching Siberia. The Laurentide Ice Sheet grew rapidly at the onset until it covered essentially all of Canada east of Rocky Mountains. In the Southern Hemisphere Patagonian Ice Sheet covered the whole southern third of Chile and adjacent areas of Argentina.
Sea level was about 125 meters lower than it is today when the Last Glacial Maximum peaked. Lowered sea levels joined many islands to continents creating vast landmasses like Sundaland. Extensive coastal plains formed where oceans once covered the land.