To most of us, soil is often seen as a dirty concoction of muddy sediments and slimey worms, especially after a downpour. It’s a pain to deal with the earthly stains if one happens to carelessly slip and fall. But why do we have such strong feelings of disgust for something that is essential for the circle of life, in which we are unavoidably a part of? The answer lies within the minimal amount of contact we urbanites have with nature; also known as nature deficit disorder (or NDD). NDD arises when we are sheltered under cemented structures most of the time, thereby moulding our negative impressions of soil. In reality, soil is just as vital as air and water to us. The dirt that we have taken for granted all the time is one of the most critical carbon sinks we cannot afford to lose in the fight against climate change.
We are, however, losing this important carbon sink grain by grain. Global soils hold carbon three times more than the atmosphere can hold, and even so, there is still potential room for more (Ngumbi, 2016)! However, the extreme climate induced by anthropogenic developments are causing unexpected, long-term disturbances to the physical, chemical and biological properties of soil. For instance, a rise of 0.13°C per decade was observed in Canada’s land surface temperature from 1956 to 2005—that is 0.65°C in total over the 50 years—indicating that the land is warming up faster than the ocean (Qian, Gregorich, Gameda, Hopkins, & Wang, 2011). Don’t be misled by the numbers—though the difference is small, the effects are not.
In addition, soil is host to countless microbial communities—the engineers behind the biogeochemical transformations in nature. These microscopic organisms are the ones that are extremely sensitive to changes in temperatures. An astounding 26-year study focusing on the effects of warming of soil was conducted in Harvard Forest, and the results showed that a rise in temperature would most likely alter microbial community composition and, most importantly, the efficiency of microbial carbon use. These effects would undoubtedly intensify carbon emissions from soils (Melillo et al., 2017).
Since it is nearly impossible to reverse the effects of global warming over a short period, it is inevitable that the carbon emissions from soils will spike in the near future. This will then contribute to a warmer climate, resulting in a never-ending cycle of warm climatic conditions. This therefore does not give us a reason to idle and wait. Preventing land degradation has been proven to be a substantially effective method, as the microbes will return to their “carbon- storing” mode if the environment is favourable (Paustian et al., 2016). But how can individuals like you and me contribute? It’s not as hard as it seems. Start by developing an appreciation for soil with your actions and words, and in the process, you might not find soil to be dirty after all.
Harvey, V. (2017, October 5). Carbon emissions from warming soils could trigger disastrous feedback loop. The Guardian. Retrieved from https://www.theguardian.com/environment/2017/oct/05/carbon-emissions-warming-soils-higher-than-estimated-signalling-tipping-points
Melillo, J. M., Frey, S. D., DeAngelis, K. M., Werner, W. J., Bernard, M. J., Bowles, F. P., Pold, G., Knorr, M. A., & Grandy, A. S. (2017, October 6). Long-term pattern and magnitude of soil carbon feedback to the climate system in a warming world. Science, 358(6359), 101 – 105. Retrieved from http://science.sciencemag.org/content/358/6359/101
Ngumbi, E. (2016, May 17). How Soil Microbes Fight Climate Change. Scientific American. Retrieved from https://blogs.scientificamerican.com/guest-blog/how-soil-microbes-fight-climate-change/
Paustian, K., Lehmann, J., Ogle, S., Reay, D., Robertson, G. P., & Smith, P. (2016, April 7). Climate- smart soils. Nature, 532, 49 – 57. Retrieved from https://www.nature.com/nature/journal/v532/n7597/full/nature17174.html
Qian, B., Gregorich, E. G., Gameda, S., Hopkins, D. W., & Wang, X. L. (2011). Observed soil temperature trends associated with climate change in Canada. Journal of Geophysical Research, 116, D02106. Retrieved from http://onlinelibrary.wiley.com/doi/10.1029/2010JD015012/full
NUS Bachelor of Environmental Studies