By Kavindra Sahabir ‘21

Climate change, in addition to contributing to rising temperatures around the globe, may also be affecting the availability of water and production of food.

Soil macropores are, at their most basic level, holes in soil that act as natural drains of water due to gravity. They affect factors such as nutrient transport for plants and water runoff in fields, which in turn affects factors such as water availability and food security. These cavities are responsible for about 70% of water that gets to the soil; however, they make up only about 1% of total soil volume in the world (1).

Research conducted by a team led by Daniel Hirmas at the University of California involved testing soil samples from five different regions across the USA, looking for differences in organic matter (1). They found that macropores are more likely to form in drier climates than in humid climates, as drier soil is more likely to break apart and collapse. They also found that the saturated soil hydraulic conductivity, or the ability of soil to allow water to pass through it, is predicted to increase as a result of climate change. Based on these two factors, the researchers concluded that these changes, which take place on a continental scale, would cause a large-scale increase in the formation of macropores, which would increase the amount of water in the water cycle, intensifying its effects, and could potentially lead to an increase in natural disasters, such as hurricanes and monsoons.

References

1. D.R. Hirmas, et. al., Climate-Induced Changes in Continental-Scale Soil Macroporosity May Intensify Water Cycle. Nature 561, 100-103 (2018). doi: https://doi.org/10.1038/s41586-018-0463-x  
2. Image retrieved from: https://commons.wikimedia.org/wiki/File:What_does_healthy_soil_look_like%3F_Photos_from_Davison_County,_SD_photo_2_of_2_(14089718314).jpg