The impact of climate change is known to be far-reaching with effects on our coastlines, oceans, local ecosystems, weather patterns, and even human health. And now climate change impact on soil may be changing the very dirt we rely on for our food supply.
Research indicates that climate change may reduce the ability of soil to absorb water in some areas around the world. This effect could have alarming implications for the worldwide food supply, stormwater runoff, and groundwater contamination, as well as creating problems in biodiversity and ecosystems.
The study, published in the peer-reviewed multi-disciplinary journal, Science Advances, is co-authored by Daniel Giménez, a professor in the Department of Environmental Sciences at Rutgers University-New Brunswick.
“Since rainfall patterns and other environmental conditions are shifting globally as a result of climate change, our results suggest that how water interacts with soil could change appreciably in many parts of the world, and do so fairly rapidly,” said Giménez.
Changes in soil could lead to lasting consequences since water in the soil is essential for the storage of carbon. Variations on this level could impact the amount of carbon dioxide in the atmosphere. The effect of changing levels of CO2 is difficult to predict, according to Giménez. Research has established that carbon dioxide is a crucial player in climate change, as one of the elements of greenhouse gases.
Water absorption in soil is vital on several levels. The amount of precipitation that is absorbed by soil determines how much water will be available for use by plants and how much will evaporate. Increased precipitation over just one or two decades can change the amount of water infiltration to soil and thus water availability for plants. Rainfall is predicted to increase in many parts of the world due to climate change.
An earlier study published last year by Giménez in the scientific journal Nature indicated that localized or regional increases in precipitation could create more extensive problems. These issues include more water runoff, soil erosion, lessened water filtration, and increased risks of flash floods.
A long term study led by the Rutgers team found that increases in rainfall over time could lead to a significant reduction in water infiltration rates. The experiment was conducted over 25 years in Kansas and examined the irrigation of prairie soil with sprinklers. The scientists found that a 35 percent increase in rainfall led to a 21-33 percent reduction in the rate of water infiltration with a minor increase in water retention.
Significant changes were found in large spaces, called pores, in the soil. Water collects in the pores and is available for plants and microorganisms. This process enhances nutrient cycling in the soil, increases biological activity, and lessens the amount of soil lost to erosion. Due to the increase in rainfall, however, plants grew thicker roots, which clogged the spaces in the soil, lessening the ability of the soil to expand and contract with water.
Further investigation is recommended in the observed climate change impact on soil to predict how more extensive ecosystems will react to the changing climate. Researchers agree additional studies are needed on broader environmental factors that may influence other changes in different soil types.
Joshua S. Caplan, now at Temple University, led the study, and researchers from the University of California, Riverside, University of Kansas, Kansas State University, and Colorado State University contributed to the study.