TOEFL Integrated Writing Practice Test 039Ice Age Mini

The Little Ice Age was a period of unusually cold temperatures that affected many regions of the world from around 1350 to 1900 CE. Harsh winters and the expansion of glaciers were characteristic of this time. Scientists have proposed several possible causes for the Little Ice Age.

First, the cooling may have been caused by a disruption of ocean currents. Prior to the Little Ice Age, there was a period of warm weather during which glaciers melted, sending large amounts of cold freshwater into the Gulf Stream, a major ocean current that influences Earth’s climate. Some scientists believe this influx of freshwater disrupted the Gulf Stream, potentially triggering the Little Ice Age.

Second, volcanic eruptions could have contributed to the cooling. Volcanic activity releases dust and sulfur gases into the atmosphere, forming clouds that block sunlight from reaching Earth’s surface. This reduction in sunlight can lower global temperatures. Several volcanic eruptions occurred during the Little Ice Age, which could have played a role in cooling the climate.

Third, decreases in human populations may have indirectly contributed to the cooling. Due to factors such as disease, warfare, and social upheaval, the human population declined just before and during the early stages of the Little Ice Age. As agricultural fields were abandoned, forests began to grow in these areas. Trees absorb carbon dioxide, a greenhouse gas that helps retain heat in the atmosphere. With more trees absorbing carbon dioxide, the greenhouse effect weakened, leading to cooler temperatures.