Lesson 4.1 (Geological Timeline)

Data from scientific studies that used fossils and ice core data indicate that the peat that is part of the peat/permafrost system found today in the Arctic formed approximately 11,000 years ago from living plants that died and have been decomposing ever since at a very slow rate.

It is estimated that there are 1.5 trillion metric tons of organic carbon in the peat/permafrost system. That is a lot of carbon! It is twice as much carbon as what is currently found in the Earth’s atmosphere.

How could enough plants to produce all the carbon found in the peat grow in the Arctic where it is so cold?

Data from the Arctic suggests that 11,000 years ago when the peat formed, the Arctic was a little bit warmer than it is today. There are several factors that could contribute to a warmer Arctic including the tilt of the Earth. Over geologic time, the angle of the Earth’s tilt changes the amount of solar radiation that reaches the surface of the Earth. Currently the tilt of the Earth is 23.5 degrees (nasa.gov). When the plants that formed the peat were growing, the Earth was even more tilted. This means that the Arctic experienced more solar radiation for a longer period of the year. As the tilt of the Earth decreased, less solar radiation was available in the Arctic. The Arctic cooled at this time followed by peat formation and a layer of permafrost.