Permafrost

Permafrost is frozen ground that stays below 0 °C (32 °F) for at least two years. It can be found in many places, including Alaska, Canada, Greenland, and Siberia. Some permafrost has been frozen for around 700,000 years, while other parts are much younger.

This frozen ground plays an important role in our environment. It holds a lot of old plant and animal material that has not broken down because it was too cold. As the world gets warmer, this permafrost is starting to melt, which can change the climate. When it melts, the frozen material begins to break down and release gases that can trap heat, making the Earth even warmer.

Besides affecting the climate, melting permafrost can also cause problems for buildings and infrastructure built on the frozen ground. As the ground thaws, it can shift and even collapse, putting many structures at risk. Scientists are also watching to see if any harmful materials trapped in the frozen ground might be released as it melts.

Classification and extent

Permafrost is soil, rock or sediment that stays frozen for more than two years in a row. This usually happens in places where the average temperature is below 0 °C (32 °F). In very cold areas, the frozen ground can be more than 1,400 meters deep. Permafrost is often found under a layer of soil that freezes in winter and thaws in summer, called the active layer. This active layer allows plants to grow because their roots can stay in the thawed soil.

About 15% of the land in the Northern Hemisphere that isn’t covered in ice has permafrost underneath. In some places, like Siberia, Alaska, and Greenland, the permafrost is very thick and the active layer is thin. In other areas, like southern Norway and the Mongolian Plateau, the active layer can be much thicker, sometimes even up to 10 meters deep.

Manifestations

Permafrost is ground that stays below 0 °C (32 °F) for at least two years. It can be very shallow, less than a meter deep, or much deeper, over 1,500 meters. The depth of permafrost depends on factors like the type of soil and the amount of heat coming from inside the Earth.

When permafrost contains a lot of ice—more than 250 percent of the soil’s weight—it is called massive ground ice. This ice can be in many forms, from icy mud to pure ice, and can be quite large. Massive ice can form in different ways, such as from frozen lakes, rivers, or even ancient glaciers. These ice formations are important for scientists studying Earth’s past climate.

Permafrost can also shape the land. When it thaws, it can create interesting patterns on the ground, like circles and polygons. In areas with lots of ice, melting can lead to the formation of lakes and other landforms. Only certain plants, like some types of spruce trees, can grow in permafrost areas because they have shallow roots. Even tiny microorganisms can survive in frozen ground, and they play a role in Earth’s carbon cycle.

Impacts of climate change

Permafrost is soil or underwater sediment that stays below 0 °C (32 °F) for at least two years. It is found in places like the Arctic and high mountains. As the Earth warms, permafrost is thawing, which can cause many problems.

Thawing permafrost can change the ground, making it unstable. This can affect buildings, roads, and pipelines. In places like Alaska and Siberia, many structures are built on permafrost, and as it thaws, these structures can become damaged. Scientists are studying how to protect these important places.

Thawing permafrost can also release carbon that has been stored for thousands of years. This carbon can become carbon dioxide or methane, which are gases that trap heat and make the Earth warmer. This creates a cycle where warming causes more thawing, which causes more warming. Scientists are working to understand how big this effect will be and how it might change the climate in the future.

History of scientific research

Between the mid-1800s and mid-1900s, most of the early studies about permafrost were written in Russian. One of the first written reports about permafrost happened in Yakutsk in 1684, when people were surprised to find frozen ground while digging wells.

Important scientists like Alexander von Middendorff and Karl Ernst von Baer helped start serious research on permafrost. Baer began sharing his ideas about permafrost in 1838 and is often called the founder of scientific permafrost research. He even wrote the world’s first textbook about permafrost in 1843, though it wasn’t printed until much later.

In 1942, a scientist named Siemon William Muller studied Russian writings on permafrost and helped create the first guide for engineers in the United States. The first big international meeting about permafrost happened in 1963 at Purdue University in West Lafayette, Indiana, with scientists from many countries joining together. Since then, scientists have kept meeting every five years to share what they learn.

Today, permafrost research is very important because of its connection to climate change. Many scientists are now studying how permafrost affects the world, and the number of research papers about permafrost has grown a lot over the past few decades.