CLIMATE CHANGE MITIGATION: reducing/preventing emissions of greenhouse gasses. There are numerous ways to do that such as using new technologies, changing consumer behavior, or even just walking or riding a bike instead of driving.
ANTHROPOGENIC: "Change in sea surface pH caused by anthropogenic CO2 between the 1700s and the 1990s. This ocean acidification will still be a major problem unless atmospheric CO2 is reduced. Various criticisms have been made of geoengineering, particularly Solar Radiaton Management (SRM) methods."