Permafrost temperatures with depth in a borehole in East Teshekpuk, Alaska (US) taken in 1989, 1995, and 2001 showing significant temperature increase in the upper 40 meters over time.
Click on image for full size
Global Warming and Thawing Permafrost
Temperature measurements taken in deep boreholes, such as those in the graph at the left, show that permafrost temperatures have increased significantly over recent years. Data like this has been collected from permafrost-covered lands in northern North America, Europe and Asia over the past 50 years. The data from different locations shows similar trends toward permafrost thaw over time, and the thawing trend appears to be accelerating.
As permafrost thaws, the land, atmosphere, water resources, ecosystems, and human communities are affected. In some natural areas, forests have turned into wetlands filled with newly available water that was once trapped in the ice. The thawed ground is often less stable causing trees to topple and lean in odd directions. These areas are called drunken forests. Homes and other buildings built on frozen ground settle or collapse as the land thaws. More than 300 buildings in and around Fairbanks, Alaska (US) have been affected by thawing permafrost. When the ground thaws, coastal areas and hillsides are also vulnerable to erosion. Unstable slopes can pose a danger for human settlements and roads. The eroding ground can cause damage to pipelines too.
Thawing permafrost also causes a positive feedback to global warming. Permafrost is a sink for carbon. The carbon became trapped underfoot when the soils froze during the beginning of the last ice age in the Pleistocene. As permafrost thaws, carbon trapped within the once-frozen soils is released as methane, a powerful greenhouse gas. The methane released to the atmosphere causes more global warming and more permafrost thaws. Thus, thawing permafrost actually speeds up global warming.
Shop Windows to the Universe Science Store!
The Winter 2009 issue of The Earth Scientist
, focuses on Earth System science, including articles on student inquiry, differentiated instruction, geomorphic concepts, the rock cycle, and much more!
You might also be interested in:
When the ground under your feet is frozen, interesting things can happen. The land may be covered with circles, polygons, or stripes, called patterned ground, which form as the land freezes. Trees may...more
Methane is gas that is found in small quantities in Earth's atmosphere. Methane is the simplest hydrocarbon, consisting of one carbon atom and four hydrogen atoms. Methane is a powerful greenhouse gas....more
Less than 1% of the gases in Earth's atmosphere are called greenhouse gases. Even though they are not very abundant, these greenhouse gases have a major effect. Carbon dioxide (CO2), water vapor (H2O),...more
Humans significantly alter the Earth. Big Idea 9.1 Human activities significantly change the rates of many of Earth’s surface processes. Humankind has become a geological agent that must be taken into...more
Essential Principles and Fundamental Concepts of Climate Science Earth’s climate offers just the right conditions for life to thrive. Climate is the average weather over a long period of time — at least...more
Polar exploration includes the physical exploration of the Arctic and the Antarctica. The Arctic is the area around the Earth's north pole and includes parts of Canada, Greenland, Russia, the United States...more
What Will You Find There? South of the Antarctic Circle (at 66.5°S latitude) you will find the continent of Antarctica surrounded by the Southern Ocean, the geographic South Pole and the magnetic South...more