The term "Ice Age" refers to several periods in Earth's history characterized by extensive glaciations, where ice sheets covered significant portions of the planet.

These periods were marked by drastic climatic changes and temperature fluctuations that had profound effects on the global environment.

Understanding how cold the Ice Age was involves examining various aspects, including temperature variations, ice coverage, and the impact on Earth's ecosystems.

The term "Ice Age" often refers to the Pleistocene Epoch, which began around 2.6 million years ago and lasted until about 11,700 years ago. This period was marked by repeated glaciations, where massive ice sheets expanded and receded in cycles.

The most recent glacial period, known as the Last Glacial Maximum (LGM), occurred approximately 20,000 years ago, when ice sheets were at their maximum extent.

During the Ice Age, global temperatures were significantly lower than today's averages. While exact temperatures can vary depending on the location and time within the Ice Age, it is generally estimated that temperatures were about 5 to 10 degrees Celsius (9 to 18 degrees Fahrenheit) cooler than the present day.

In regions covered by ice sheets, such as parts of North America, Europe, and Asia, temperatures were considerably colder.

For instance, in what is now Canada and northern parts of the United States, temperatures during the Last Glacial Maximum were approximately 10 to 15 degrees Celsius (18 to 27 degrees Fahrenheit) colder than today's averages.

The vast ice sheets in these areas created extremely frigid conditions, with temperatures dropping as low as -40 degrees Celsius (-40 degrees Fahrenheit) in some regions.

The extent of ice coverage during the Ice Age was immense. At the peak of the Last Glacial Maximum, ice sheets covered about 30% of Earth's land surface, compared to around 10% today.

The most notable ice sheets were the Laurentide Ice Sheet, which covered much of North America, and the Eurasian Ice Sheet, which extended across northern Europe and Asia.

These ice sheets had a profound impact on global sea levels. During the Ice Age, sea levels were approximately 120 meters (394 feet) lower than present levels due to the large volumes of water trapped in ice.

This lowered sea levels exposed land bridges, such as Beringia, which connected Asia to North America and facilitated the migration of species, including early humans.

Temperature variations during the Ice Age were not uniform across the globe. While some regions experienced extreme cold, others were relatively milder. For example, areas closer to the equator, such as parts of Africa and South America, experienced less dramatic temperature drops.

However, even in these regions, the effects of the Ice Age were felt, with changes in vegetation and animal migrations due to altered climate patterns.

In addition to temperature changes, the Ice Age had significant impacts on weather patterns and ecosystems. The massive ice sheets influenced atmospheric circulation, leading to altered precipitation patterns.

In some regions, this resulted in the development of expansive tundra landscapes, while others experienced more arid conditions.

The extreme cold of the Ice Age presented both challenges and opportunities for early humans. The harsh climate forced humans to adapt to new environments, develop advanced tools, and create strategies for survival.

Evidence of human adaptation during this period includes the use of animal hides for clothing, the construction of insulated shelters, and the development of sophisticated hunting techniques to target large Ice Age megafauna such as mammoths and woolly rhinoceroses.