Human emissions of fossil carbon into the atmosphere and the resulting increase in temperatures may be holding off the next ice age, according to research from Sweden’s University of Gothenburg.
“We are probably entering a new ice age right now,” Lars Franzen, a professor of physical geography at the university, was cited as saying in an online statement today. “However, we’re not noticing it due to the effects of carbon dioxide.”
Franzen and three other researchers calculated how much of Sweden might be covered by peat lands during an interglacial, the period between two ice ages. Peat absorbs carbon from the atmosphere, and the study found that the country’s carbon-sink potential could increase six- to 10-fold, which theoretically might cause a drop in temperatures.
Increased felling of woodlands and expansion of agricultural land, combined with early industrialization, probably halted the so-called Little Ice Age from the 16th to the 18th century, slowing down or even reversing a cooling trend, according to the researchers.
“It’s certainly possible that mankind’s various activities contributed towards extending our ice age interval by keeping carbon dioxide levels high enough,” Franzen said. “Without the human impact, the inevitable progression toward an ice age would have continued.”
The earth experienced at least 30 periods of ice age in the past 3 million years, according to the university. There were no emissions of fossil carbon in earlier interglacial periods, and carbon sequestration in peat lands may have been one of the main reasons why ice age conditions occurred, according to Franzen.
“The spread of peat lands is an important factor,” Franzen said. “If we accept that rising levels of carbon dioxide in the atmosphere lead to an increase in global temperature, the logical conclusion must be that reduced levels lead to a drop in temperature.”
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