Joel Sankey a researcher at the US Geological Survey, told the Geological Society of America’s annual meeting in Baltimore, Maryland, that by 2050 an increase in wildfires may double soil erosion in some western states. As a consequence, soil would blow or be washed into water courses.
He and his colleagues used computer models to see what projected increases in wildfire could do throughout the West in the first half of this century.
Researchers have already warned that California’s present sustained drought is an indicator of things to come, and that rising average temperatures and more frequent heat waves must mean greater wildfire hazards.
Rich mix
But the scientists looked beyond the drought and fire to see the consequences for soil erosion.
Topsoil is a rich mix of weathered rock, minerals, trace elements and decaying vegetation that supports a huge community of tiny living things that recycle nutrients. It is the natural substrate that absorbs and holds water and nourishes all green growth. Topsoil also underwrites the wealth of the US, a great agricultural power.
But fire can change the nature of the soil, turning it into hot, charred dust that can blow away in the wind, or – equally dangerously – baking its surface so that falling rain or melting snow runs off directly, rather than percolating into the sediment. Either way, the topsoil can end up in the nearest creek, to choke rivers or muddy the reservoirs.
“We can identify municipalities that are future hotspots, and figure out how fire and erosion impact that community”
“The sediment can have a wide range of effects on a lot of watersheds, many of which are headwater streams and important for water supply in the West,” Dr Sankey says.
The models predicted that erosion would at least double in a quarter of western US watersheds. Two-thirds of the watersheds are projected to experience at least 10% more erosion by mid-century.
Read more at Scorched Earth Threat to US Agriculture
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