Thank you Hendrik Smith for sharing.
AbstractThe ‘4 per mille Soils for Food Security and Climate’ was launched at
the COP21 with an aspiration to increase global soil organic matter
stocks by 4 per 1000 (or 0.4 %) per year as a compensation for the
global emissions of greenhouse gases by anthropogenic sources. This
paper surveyed the soil organic carbon (SOC) stock estimates and
sequestration potentials from 20 regions in the world (New Zealand,
Chile, South Africa, Australia, Tanzania, Indonesia, Kenya, Nigeria,
India, China Taiwan, South Korea, China Mainland, United States of
America, France, Canada, Belgium, England & Wales, Ireland,
Scotland, and Russia). We asked whether the 4 per mille initiative is
feasible for the region. The outcomes highlight region specific efforts
and scopes for soil carbon sequestration. Reported soil C sequestration
rates globally show that under best management practices, 4 per mille or
even higher sequestration rates can be accomplished. High C
sequestration rates (up to 10 per mille) can be achieved for soils with
low initial SOC stock (topsoil less than 30 t C ha
− 1), and
at the first twenty years after implementation of best management
practices. In addition, areas which have reached equilibrium will not be
able to further increase their sequestration. We found that most
studies on SOC sequestration only consider topsoil (up to 0.3 m depth),
as it is considered to be most affected by management techniques. The 4
per mille number was based on a blanket calculation of the whole global
soil profile C stock, however the potential to increase SOC is mostly on
managed agricultural lands. If we consider 4 per mille in the top 1m of
global agricultural soils, SOC sequestration is between 2-3 Gt C year
− 1,
which effectively offset 20–35% of global anthropogenic greenhouse gas
emissions. As a strategy for climate change mitigation, soil carbon
sequestration buys time over the next ten to twenty years while other
effective sequestration and low carbon technologies become viable. The
challenge for cropping farmers is to find disruptive technologies that
will further improve soil condition and deliver increased soil carbon.
Progress in 4 per mille requires collaboration and communication between
scientists, farmers, policy makers, and marketeers.