What are some things that have contributed to increased global temperatures due to higher levels of carbon dioxide?

There are many lines of evidence which clearly show that the atmospheric CO2 increase is caused by humans. The clearest of these is simple accounting - humans are emitting CO2 at a rate twice as fast as the atmospheric increase (natural sinks are absorbing the other half). There is no question whatsoever that the CO2 increase is human-caused. This is settled science.