Learning about the realities of pollution arising from the sourcing of climbing chalk in my previous post had me wondering if the usage of chalk in natural rock climbing could lead to similar negative impacts, albeit likely to a much smaller extent since the amount of chalk used by climbers would most certainly be less than the dust emissions produced through mining.
Academic literature has reported that rock climbers create disturbances in the natural environment due to trampling, clearing of vegetation, placement of crash-pads or the drilling of bolts for new routes (Adams & Zaniewski, 2012; Boggess et al., 2021; Tessler & Clark, 2016). However, up till recently, there has not been any studies done on the pollutive effects of climbing chalk on surrounding vegetation.
In 2020, Hepenstrick et al published an ex situ study on the effects of climbing chalk on the germination and survival rate of ferns and moss species on climbed boulders. Their work discovered that chalk levels from just a 1mm thick layer of 50% saturated climbing chalk medium could lead to significant growth impairment in certain species of plants. Similar to the pollution caused by magnesite mining, the alkaline properties of climbing chalk raises the pH levels of the soil substrate when it becomes diluted. As mentioned in Hepenstrick et al (2020), the solubility of climbing chalk depends on the acidity of rain and highly acidic rainfall could cause even further increases in pH. In outdoor environments, rock type could also play a role in enhancing solubility such as in the case of gneiss, an acidic siliceous rock. At high pH levels, plant germination and growth are impacted since nutrient uptake is pH sensitive (Barker & Pilbeam, 2015 in Hepenstrick et al., 2020).
Given that the study was conducted in laboratory conditions, these results may not be accurately reflected to the same extent in situ. However it is important to keep in mind these potentially harmful effects climbing chalk can have and exercise caution when using it in the outdoors, particularly in areas with threatened plant species, while we await confirmation from future studies. In the meantime, perhaps more people could consider a switch from loose chalk to chalk balls instead.
Chalk balls are slightly porous bags that can be filled/re-filled with powdered chalk. Compared to traditional loose chalk, chalk balls do not create dust clouds when being applied onto hands and help to reduce accidental spillage (e.g. when the chalk bag is knocked over). This can help to reduce the amount of chalk entering the environment.
Since starting this blog, I’ve also read up about new types of chalk being made from more sustainable components which I’m excited to share about in the subsequent posts. Thanks for reading!
References
Adams, M. D., & Zaniewski, K. (2012). Effects of recreational rock climbing and environmental variation on a sandstone cliff-face lichen community. Botany, 90(4), 253-259.
Boggess, L. M., Harrison, G. R., & Bishop, G. (2021). Impacts of rock climbing on cliff vegetation: A methods review and best practices
Hepenstrick, D., Bergamini, A., & Holderegger, R. (2020). The distribution of climbing chalk on climbed boulders and its impact on rock‐dwelling fern and moss species. Ecology and evolution, 10(20), 11362-11371.
Tessler, M., & Clark, T. A. (2016). The impact of bouldering on rock-associated vegetation. Biological Conservation, 204, 426-433.
