Unprecedented wind erosion and perturbation of surface geochemistry marks the Anthropocene in Australia

Abstract

Australia, the last continent to undergo industrial development, is an ideal environment in which to quantify the magnitude of human-induced environmental change during the Anthropocene because its entire agricultural and industrial history has occurred within this period. Analysis of an alpine peat mire showed that rapid industrial and agricultural development (both pastoral and cropping) over the past 200 years has resulted in significant environmental change in Australia. Beginning in the 1880s, rates of wind erosion and metal enrichment were up to 10 and 30 times that of background natural conditions, respectively. Increased dust deposition and an expansion in dust source areas were found to map the progression of European farming across the continent,while dust deposition pulses in the mire matched known land degradation events. After 1990 dust deposition decreased, returning to pre-1880 rates. This was attributed to three factors: net soil loss following more than a century of agricultural activity, increased environmental awareness and soil conservation, and changing windiness. Metal enrichment in the mire reached approximately 2 times natural background accumulation rates by the 1980s as Australia's mining industry expanded. However, metal enrichment continued to increase after the 1980s reaching an average of ~5 times background rates by 2006 and reflecting increased mineral resource development in Australia. Collectively, the results show that changes to Australia's geochemical and sedimentary systems, as a result of agricultural and industrial development, have profoundly changed the Australian environment during the past two centuries.