Think there’s a lot of carbon dioxide in the atmosphere? Well, there’s more than twice the amount of carbon held in the earth’s soil than in the atmosphere, and there are now new warnings over the risk of this carbon being released into the atmosphere with rising temperatures.
Researchers have discovered that the massive amounts of carbon stored in soils are more at risk of being released as carbon dioxide into the atmosphere than previously thought. The scientists found that microbes in the soil are more likely to increase the release of CO2 as the earth warms. The soils seen to emit the most extra carbon with rises in temperature were cold soils and those rich in carbon.
Microbes in the soil already release around 60 billion tonnes of carbon dioxide into the atmosphere each year, so if this figure is expected to rise with global warming then i believe this is definitely an area of concern.
The lead author, Dr Kristiina Karhu from the University of Helsinki said “There were some suggestions that microbes could get accustomed to higher temperatures with climate warming and then the temperature sensitivity of soil respiration would decline.” The scientists tested 22 different soil types, from the Amazon to the Arctic. “We show that for these 22 soils, this type of acclimation of microbial respiration doesn’t really happen. Sometimes the opposite happens, in response to long term temperature change, the microbes enhance the short term effect of temperatures so that the sensitivity of respiration gets actually higher.”
The researchers found that soils from the arctic and boreal regions were affected the most by the temperature increase, with the greatest extra amount of CO2 released. Soils from managed and arable lands showed the most little change. Dr Karhu said that “the soils that had this enhancing response were also soils that had a high carbon to nitrogen ratio.” The scientists aren’t yet entirely sure about the mechanisms of action involved, so more research is needed.
I believe this is an area worth investing research into, as if the amount of CO2 released from soils increases with increasing temperature, then this will speed up and propel global warming. It could be a vicious circle: as the earth warms more due to increased CO2, more CO2 is released into the air from soils, and so it goes on.
Information source: http://www.bbc.co.uk/news/science-environment-29050800