Warm autumns increase natural carbon dioxide emissions

If future autumn warming occurs at a faster rate than spring warming, the ability of northern ecosystems to sequester carbon may be diminished earlier than previously suggested.

Forest and instrumentation Scientists from the University of Helsinki have made a significant contribution to global climate change research. Their article, published in Nature on 3 January 2008, shows that European forests are releasing carbon dioxide into the atmosphere during warm autumns.

In the autumn, forest ecosystems act as sources of carbon dioxide, and according to research, autumn warming lengthens the period when forests release carbon dioxide.

“The autumn of 2006 was clearly warmer than average,” says Professor Timo Vesala from the Department of Physical Studies at the University of Helsinki, “and over a number of weeks, the maximum levels of carbon dioxide released were twice as high as the average over the past ten years."

In the spring, forests absorb carbon dioxide while in the autumn, they release it. Since global warming increases plant growth and thereby increases the carbon absorption, it has been speculated that this would decrease the amount of carbon dioxide released.

However, autumn warming happens faster than spring warming, leading to a diminishing of the ability of northern ecosystems to sequester carbon earlier than previously suggested.  

Climate change involves several interlinked factors, so there is no shortage of research topics:

“Owing to the carbon dioxide emission caused by man, the natural carbon cycle may be disturbed. It is vital to take this into account in all climate change research,” says Vesala.

For further details, see more on the Nature website: Net carbon dioxide losses of northern ecosystems in response to autumn warming

Text: Tapani Sainio ja Minna Meriläinen
Photo: Pertti Hari

Translation: Valtasana Oy
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