Vast farming projects eroding earth's surface

Mammoth farming projects can erode the earth's surface at rates comparable to those of the world's largest rivers and glaciers. A new University of British Columbia (UBC) study offers stark evidence of how humans are reshaping the planet. It also finds that contrary to previous studies, rivers are as powerful as glaciers at eroding landscapes. 'Our initial goal was to investigate the scientific claim that rivers are less erosive than glaciers,' says Michele Koppes, UBC professor of geography and lead study author. 'We found that many of the areas currently experiencing the highest rates of erosion are being caused by climate change and human activity such as modern agriculture,' says Koppes, who conducted the study with David Montgomery of Washington University. The highest erosion rates have typically been seen at high altitudes where tectonic forces pit rising rock against rivers and glaciers, says Koppes. He created an updated database of erosion rates with Montgomery, for more than 900 rivers and glaciers worldwide, documented over the past decade with new geologic measuring techniques. In some cases, researchers found large-scale farming eroded lowland agricultural fields at rates comparable to glaciers and rivers in the most tectonically active mountain belts, says an UBC release. 'This study shows that humans are playing a significant role in speeding erosion in low lying areas,' says Koppes. 'These low-altitude areas do not have the same rate of tectonic uplift, so the land is being denuded at an unsustainable rate.' The study was published online in Nature Geoscience.