Just a few comments:
Ron - I think Vandana Shiva's cautions about biochar and other
geoengineering ideas ("role ... should be zero") may be rhetorically
overstated. But I just want to look at biochar to the extent that it can be
called geoengineering. If I could characterize your views, you generally
look to extrapolate the role of biochar to sequester the maximum
atmospheric CO2. That would be large-scale geoengineering, I think we would
agree. And because there could be substantial benefits to soil and energy
supply, you argue that this is a superior tool to other CDR proposals.
Just removing CO2 from the atmosphere won't cool the planet quickly enough,
because of numerous sinks and feedbacks. I advocate soil carbon
sequestration for other primary benefits: reversing aridification of
enormous areas of land that are increasingly radiating heat because of
losing vegetative cover, reversing the damages done by industrial
agriculture which have depleted carbon with the plow and with chemical
inputs killing off microbes and other soil organisms, and restoring
hydrology that comes from forests providing the biological seeds for
clouds, and from supporting microclimates to hold moisture in the soil.
These benefits use water vapor effects that cool much more effectively than
CO2 reduction.
And yes, CO2 being sequestered is also urgent. Biochar obviously does that.
But if you think that biochar has to be given the whole job, the logistical
side-effects could be disastrous. I'd rather see us use biochar in
concentrated doses (after all, it's still very expensive) as a catalyst and
stimulant to effective prime soil carbon. quickly boosting mychorrizal
fungi and microbial communities, and regreening landscapes. The soil carbon
is the priority, and biochar is an invaluable tool for the purpose.
We agree on a lot of things about biochar. I just think you're putting the
cart before the horse.
Brian
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