Garbage In – Carbon Out:
Climate Change Mitigation
Potential of Grassland Soils
Whendee L. Silver
’87 M.F.S., ’92 Ph.D.
Professor of Ecosystem Ecology,
University of California, Berkeley
Grasslands cover approximately 30% of the terrestrial
land surface. This large land area and the propensity of
grassland vegetation to store carbon (C) in soils
suggest that even low rates of C sequestration could
result in a significant sink of atmospheric CO2. We
explored the use of composted organic material on
rangeland soils as a mechanism to increase C storage
and decrease greenhouse gas emissions.
A one-time application of compost amendments to replicate sites in
Mediterranean grasslands in California sequestered new C at rates of 1 metric
ton (Mt) C/ha/y each year for 3 years. The compost-amended fields had
significantly higher net primary productivity, water-holding capacity, and fertility
than the control plots. Model output suggested the potential for even longerterm net gains with relatively low greenhouse gas emissions . Using a life cycle
assessment to determine the net C costs and benefits from diverting organic
wastes to compost for use on rangelands, we found that it led to additional
greenhouse gas savings of 28 million Mt CO2e when scaled to 1 million ha (5% of
CA grasslands).
12:00-1:00 FREE EVENT in Burke Auditorium, Kroon Hall
Lunch will be provided – first come, first served