Ole Humlum on CO2 Lagging Temperature
Ole Humlum published a paper about 10 years ago attempting to show that CO2 always lags temperature and therefore the increase in CO2 substantially comes from an increase in temperature, not the other way around. In the words of Humlum's paper, As cause always must precede effect, this observation demonstrates that modern changes in temperatures are generally not induced by changes in atmospheric CO2. Indeed, the sequence of events is seen to be the opposite: temperature changes are taking place before the corresponding CO2 changes occur. Papers like this almost always have multiple flaws. First, they ignore the empirical data we have for our own carbon emissions, and second, they compare monthly and/or annual changes in CO2 and temperature, rather than the overall increases in CO2 and temperature. By looking at monthly changes in CO2 and temperature, they essentially detrend the data, removing the increases in CO2 and temperature, which is precisely the data you need to look at. ...