The silicate + CO2 - > different silicate + carbonate
chemical weathering rate tends to increase with temperature globally, and so is a negative feedback (but is too slow to damp
out short term changes)-- but
chemical weathering is also affected by vegetation, land area, and terrain (and minerology, though I'm not sure how much that varies among entire
mountain ranges or climate zones)-- ie mountanous regions which are in the vicinity
of a warm rainy climate are ideal for enhancing
chemical weathering (see Appalachians in the Paleozoic, more recently the Himalayas).
And while there's nothing to worry about with the many
chemical - free lathers on the market (feel free to take a page
out of a Mad Men - style playbook and create a
mountain of froth when using them), the synthetic ingredients powering most lathering shampoos are cause for concern.