well when you go and alter the composition of the atmosphere as much as we have, what's to be expected?
Sure, volcanoes and such can put out massive amounts of gasses as well, and have climate-changing results, but we are releasing a ton of locked-up co2 (and other chemicals) -in addition to- the naturally emitted ones.
If we want to live comfortably on this planet for a long period of time, with its ice ages and hot phases, we need to work on controlling the climate deliberately on a large scale. It is within our power to do this, the technology just isn't there yet.