Carbon Dioxide Could Prevent a Future Ice Age
According to research from the University of Gothenburg, Sweden, emissions of fossil carbon and the resulting increase in temperature could prevent the earth from having a future ice age.
Over the past three million years, Earth has experienced at least 30 periods of ice age, known as ice age pulses. The researchers believe that the Little Ice Age of the 16th to 18th centuries may have been halted as a result of human activity. Increased felling of woodlands, growing areas of agricultural land, and early stages of industrialization resulted in increased emissions of carbon dioxide, which probably slowed down, or even reversed, the cooling trend.
"It is certainly possible that mankind's various activities contributed towards extending our ice age interval by keeping carbon dioxide levels high enough," explains Lars Franzén, Professor of Physical Geography at the University of Gothenburg. "Without the human impact, the inevitable progression towards an ice age would have continued. The spread of peatlands is an important factor."
Peatlands act as carbon sinks, meaning that they absorb carbon dioxide from the atmosphere. Peatlands grow in height and spread across their surroundings by waterlogging woodlands. They are also one of the biggest terrestrial sinks of atmospheric carbon dioxide. Each year, around 20 grams of carbon are absorbed by every square meter of peatland.
The relationship between carbon dioxide and temperature is not linear. Instead, lower levels result in a greater degree of cooling than the degree of warming achieved by a corresponding increase. Using calculations for Swedish conditions, the researchers are producing a rough estimate of the global carbon sink effect if all temperate peatlands were to grow in the same way.
"Our calculations show that the peatlands could contribute towards global cooling equivalent to five watts per square meter. There is a great deal of evidence to suggest that we are near the end of the current interglacial," said Franzén.