WHICH COMES FIRST WARMING OR CO2?

This is the climate science equivalent of the chicken and egg question. There is plenty of evidence from ice cores etc that over the long term the CO2 lags behind temperature by several hundred years, but what about the recent decades? Is it possible to discern any lag with such small increments? This piece on WUWT blog refers to a new paper which claims to do so, and it finds that CO2 still lags behind temperature. This should be a fatal blow to the man made global warming theory, but I don't expect the thing to die quickly, there's too much money and political capital tied up for that.