Carbon dioxide—our salvation from a future ice age?

November 8, 2012

Mankind's emissions of fossil carbon and the resulting increase in temperature could prove to be our salvation from the next ice age. According to new research from the University of Gothenburg, Sweden, the current increase in the extent of peatland is having the opposite effect.

"We are probably entering a new ice age right now. However, we're not noticing it due to the effects of ", says researcher Professor Lars Franzén.

Looking back over the past three million years, the earth has experienced at least 30 periods of ice age, known as ice age pulses. The periods in between are called interglacials. The researchers believe that the of the 16th to 18th centuries may have been halted as a result of human activity. Increased felling of woodlands and growing areas of , combined with the early stages of industrialisation, 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 , the inevitable progression towards an ice age would have continued. The spread of is an important factor."

Peatlands act as carbon sinks, meaning that they absorb carbon dioxide from the atmosphere. They are a dynamic landscape element and currently cover around four percent of the earth's land area. Most peatlands are found in temperate areas north and south of the 45th parallel.

Around 16 percent of Sweden is covered by peatland. Peatlands grow in height and spread across their surroundings by waterlogging woodlands. They are also one of the biggest terrestrial sinks of . Each year, around 20 grams of carbon are absorbed by every square metre of peatland.

"By using the National Land Survey of Sweden's altitude database, we have calculated how much of Sweden could be covered by peatlands during an interglacial. We have taken a maximum terrain incline of three degrees as our upper limit, and have also excluded all lakes and areas with substrata that are unsuitable for peatland formation."

The researchers found that around half of Sweden's surface could be covered by peat. In such a case, the carbon dioxide sink would increase by a factor of between six and ten compared with the current situation.

"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."

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.

"There have been no emissions of fossil carbon during earlier interglacials. Carbon sequestration in peatland may therefore be one of the main reasons why conditions have occurred time after time."

Using calculations for Swedish conditions, the researchers are also 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 metre. There is a great deal of evidence to suggest that we are near the end of the current interglacial."

Explore further: Northern peatlands a misunderstood player in climate change

More information: Franzén, L.G., F. Lindberg, V. Viklander & A. Walther (2012) The potential peatland extent and carbon sink in Sweden, as related to the Peatland / Ice Age Hypothesis. Mires and Peat 10(8):1-19.

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3.8 / 5 (10) Nov 08, 2012
Ouch. As a swede, I'm ashamed of Franzen, one of our few climate science denialists. This is an old kook idea of his, as a reaction to his "wonder" in front of climate science progress. [ http://www.elbran...english/ ; run through Google translate.]

"Mires and Peat" is of course no climate science journal. And it is doubtful if the paper reflect what Franzén can trumpet from his platform.
3.6 / 5 (16) Nov 08, 2012
Once upon a time the earth grew an entity called gaia. Gaia created an oxygen atmosphere so that her life forms could diversify.

Gaia got tired of all the freezing and thawing however, and so created an industrious race which would emit greenhouse gasses and thus mediate these cycles. As an added plus, this race can now spread gaia to other planets so she wont be lonely any more. Awww.
3.3 / 5 (4) Nov 08, 2012
I'm ashamed of Franzen, one of our few climate science denialists.

Even so, this is an interesting study and a really interesting theory. Certainly it does appear that in the long term, our ancesters will not likely have to deal with an ice age. In the short term, the warming arising from the greenhouse gases we`ve added to the atmosphere is going to cause a significant shift in many systems on this planet.
I`m reminded of an ancient chinese curse--may you live in interesting times.
3 / 5 (4) Nov 09, 2012
We definitely live in interesting times.

I agree with Maggnus. Our future generations will not have to deal an ice age for a much longer period than natural variability would have offered. We are witnessing the beginning of the short term variations, it will be interesting to see how creative mother nature will be with these....
2.1 / 5 (7) Nov 09, 2012
Ouch. As a swede, I'm ashamed of Franzen, one of our few climate science denialists.

Isn't he actually agreeing with the alarmists who say anthropogenic CO2 is increasing global temperatures? The only difference being that he anticipates a protective effect against ice ages?

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