Regardless of how true ice core data may or may not be, actual measurements show that the amount of carbon dioxide in the atmosphere has moved from 0.03% to over 0.04% in the last century. Why do people think this will have no consequences?
You wouldn't change reactant ratios in chemistry and expect the same result, so why do you do that with respect to planetary physics?
Anybody with a brain on /sci/ should help universities and libraries that are on coastal land with moving to higher ground.