> I’m unsure what the potential is for large scale changes in oceanic chemistry

We are down from pre-industrial 8.25 pH to 8.08, and no sign of slowing. Major changes are certain. I don't know if this means the water will dissolve more metals like Cu, but it seems possible.

Source: http://www.pmel.noaa.gov/co2/file/Hawaii+Carbon+Dioxide+Time...