Ranching and farming have eroded almost all the soil in the Alps

Rapid erosion caused by human activities like livestock grazing and farming has led to the depletion of soil in the Alps, erasing almost all the soil that accumulated since the glaciers retreated. The soil in the Alps formed over thousands of years through the interaction of plants, microbes, and weather on rock, creating a carbon-rich foundation for the mountain ecosystem.

Research conducted by William Rapuc at the French National Centre for Scientific Research involved studying lithium isotopes in sediments from Lake Bourget in the French Alps. By analyzing these isotopes, the researchers were able to track patterns of soil erosion in the region over the past 10,000 years. The data revealed that human activities started significantly impacting soil erosion around 3800 years ago, surpassing the influence of climate change.

Three distinct surges in soil loss were identified by the researchers, each corresponding to different types of human activity. The first surge, between 3800 and 3000 years ago, was attributed to livestock grazing at higher altitudes. This was followed by a surge caused by farming at lower altitudes between 2800 and 1600 years ago. The final surge, from 1600 years ago until present, was a result of more intensive agriculture practices using tools like ploughs. The accelerated erosion of soil in the Alps has decreased its capacity to support vegetation and crops.

This shift in soil erosion patterns 3800 years ago marked the beginning of a “soil Anthropocene” in the region, signifying humans as the primary drivers of soil degradation. According to Rapuc, the impact of past human activities on soils pales in comparison to the current rate of soil loss, especially in regions like the US where soil erosion is occurring up to 1000 times faster than before the last glacial period.

Daniel Rath from the Natural Resources Defense Council notes that modern agricultural practices are fundamentally altering how soils are formed and developed. The concept of a soil Anthropocene highlights the profound influence of human activities on soil health and ecosystem sustainability.