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Peat moss – A ticking climate bomb

08.01.2007

Enormous amounts of greenhouse gases are stored in areas rich in peat. If the permafrost melts, the development could go out of control.

SPHAGNUM WARNSTORFII: A small, soft plant with the power to change the global climate.

The Norwegian proverb ’small tussocks overturn great loads’ is rarely more fitting, because now it turns out that marshes and mosses are very important for the global climate.

Developmental biologist and Associate Professor at The Norwegian University of Science and Technology (NTNU), Hans K. Stenøien knows a lot about this topic:

”Peat stores one third of the global carbon reserves, and also enormous amounts of the greenhouse gas methane. If – or rather when – the average temperature on the earth rises by one centigrade, large amounts of these reserves could be released to the atmosphere. If that happens, the worst case scenario is that it no longer matters what humans do. The climatic changes may have gone out of control," Professor Stenøien says.

Changing its surroundings

Peat moss is spreading all over the world. This plant, which has not developed much since the dawn of time, is particularly robust and survives in rough environments. Besides, peat moss has a unique ability to change its surroundings and make them more favourable.

”When the peat moss invades new areas, it produces large amounts of hydroxide that makes the environment so acid that existing plants die,” the developmental biologist explains.

The extremely acid environment prevents dead plants from decomposing. Without decomposition, the carbon remains stored in layers upon layers of dead plants instead of being released.

“One acre of peat can contain as much as 2000 tonnes of carbon, and large amounts of methane,” Stenøien says.

Monster moss

Stenøien finds peat mosses fascinating. The fascination does not decrease by their ability to cause entire ecosystems to collapse.

”However, as we may see: Not only limited, local ecosystems fall to pieces if these mosses are allowed to spread. At worst, the peat mosses could make the global climate go out of control. In that case, we are talking about an apparently unimportant plant – but a plant with almost mythical dimensions,” he says.

Even small, soft plants under our feet have the power to change the foundation of the global climate.

Worst up north

Northern regions such as Siberia and North-America function as gigantic depots for these greenhouse gases. For this reason, the northern regions will be particularly affected if the depots are opened.

The global temperature has increased by 0.2 centigrade per decade since 1970. Inland Siberia has experienced an increase three times as high – and the blue line on the thermometer has climbed two steps over the past 30 years.
Siberia alone has frozen areas the size of France and Germany combined, and these areas could start melting on a large scale if the temperature rises by one centigrade. This melting will accelerate the increase in temperature, which again will cause further melting.

Other mechanisms may also produce similar feedback effects. One example is that darker surfaces in areas where ice and snow have melted, lead to higher temperatures which again results in further ice melting. And so it continues.

Has happened before?

”A lot of people believe that these feedback effects have contributed to significant global warming in earlier times,” says Stenøien.

He refers to recently published studies in Proceedings of the National Academy of Sciences, conducted by NASA’s Goddard Institute for Space Studies. If the temperature rises by one centigrade, it could in practice mean “game over” when it comes to our ability to influence the climatic development.

From then on, Mother Earth herself controls the wheel and the gas pedal – with us in the back seat.

By Tore Oksholen