Last Glacial Maximum

The Last Glacial Maximum (LGM), also called the Last Glacial Coldest Period, was the most recent time when huge ice sheets covered large parts of the world. This happened between 26,000 and 20,000 years ago, during the Last Glacial Period. Enormous sheets of ice stretched across much of Northern North America, Northern Europe, and Asia.

Because of these thick ice sheets, Earth's climate changed a lot. Many areas became much colder and drier, and deserts grew larger. The weight of the ice pushed down on the land. When the ice melted later, sea levels rose sharply.

Scientists study this time using special methods like terrestrial cosmogenic nuclides and radiocarbon dating. They found that ice sheets in the southern hemisphere began growing about 33,000 years ago. They reached their biggest size between 26,500 and 20,000 years ago. Later, as the ice melted, sea levels rose quickly, especially when parts of the West Antarctica ice sheet began to break up. This big change in our planet's ice and climate shaped the world we live in today.

Glacial climate

The Last Glacial Maximum was a very cold time about 21,000 years ago. The world's average temperature was about 6 °C colder than today. During this time, large areas of Earth were covered in ice. Sea levels were much lower—about 125 meters below what they are now.

Many parts of the world were drier and cooler. Deserts grew larger, and rainforests shrank. Some places, like parts of the western United States, had more rain and large lakes formed. In Australia, sand dunes covered much of the land. The climate was very different from today.

World impact

During the Last Glacial Maximum, much of the world was very cold and dry. Huge ice sheets held a lot of water, which made sea levels drop. This uncovered parts of the ocean floor and connected some lands that were far apart.

Ice also changed the way air moved around the world. This made temperatures even colder and created more clouds. The clouds reflected sunlight away, making the Earth even cooler.

In Africa and the Middle East, small glaciers formed in mountains, and deserts such as the Sahara grew larger. In Asia, ice covered places like modern Tibet, and lower sea levels linked islands to bigger lands. Most of Europe was covered in ice, reaching as far south as Germany and Poland. In North America, big ice sheets covered Canada and parts of the United States. South America also had more glaciers in its southern Andes mountains. All these changes greatly affected the world’s weather and shape of the land.

Late Glacial Period

The Late Glacial Period came after the Last Glacial Maximum and before the Holocene, which began around 11,700 years ago. During this time, Earth's climate changed. The big ice sheets started to melt, and the world grew warmer. These changes led to the climate we have today.