"Savannas and grasslands in drier climates around the world store more
heat-trapping carbon than scientists thought they did, helping to slow the rate
of climate warming, according to a new study.
The findings, published in Nature Climate Change
, are based on a reanalysis
of datasets from 53 long-term fire-manipulation experiments worldwide, as well
as a field-sampling campaign at six of those sites.
The researchers looked at where and why fire has changed the amount of carbon
stored in topsoil and found that within savanna-grassland regions, drier
ecosystems were more vulnerable to changes in wildfire frequency than humid
“The potential to lose soil carbon with very high fire frequencies was the
greatest in dry areas, and the potential to store carbon when fires were less
frequent was also the greatest in dry areas,” says lead author Adam Pellegrini,
currently an IGCB Exchange Professor at the University of Michigan’s Institute
for Global Change Biology. His primary appointment is at the University of
Over the last 20 years, fire suppression due to population expansion and
landscape fragmentation caused by the introduction of roads, croplands, and
pastures into savannas and grasslands led to smaller wildfires and less burned
areas in drier savannas and grasslands.
In dryland savannas, the reduction in the size and frequency of wildfires has
led to an estimated 23% increase in stored topsoil carbon. The increase was not
foreseen by most of the state-of-the-art ecosystem models used by climate
researchers, according to second author Peter Reich, a forest ecologist and
professor and director of the Institute for Global Change Biology at the
University of Michigan School for Environment and Sustainability.
As a result, the climate-buffering impacts of dryland savannas have likely been
underestimated, Reich says. The new study estimates that soils in
savanna-grassland regions worldwide have gained 640 million metric tons of
carbon over the past two decades."
Via Rixty Dixet.
*** Xanni ***
Chief Scientist, Xanadu
Partner, Glass Wings
Manager, Serious Cybernetics