At the journal Earth System Dynamics, M. Beenstock, Y. Reingewertz, and N. Paldor have published a paper titled “Polynomial cointegration tests of anthropogenic impact on global warming” which Anthony Watts describes as a potential bombshell. The authors conducted an exhaustive statistical analysis of data from 1850 through 2007, applying the technique of cointegration, which the authors describe as follows:
Cointegration theory is based on the simple notion that time series might be highly correlated even though there is no causal relation between them. For the relation to be genuine, the residuals from a regression between these time series must be stationary, in which case the time series are “cointegrated”. Since stationary residuals mean-revert to zero, there must be a genuine long-term relationship between the series, which move together over time because they share a common trend. If on the other hand, the residuals are nonstationary, the residuals do not mean-revert to zero, the time series do not share a common trend, and the relationship between them is spurious because the time series are not cointegrated.You can follow the link for the statistical details, but here is the authors’ conclusion:
We have shown that anthropogenic forcings do not polynomially cointegrate with global temperature and solar irradiance. Therefore, data for 1880–2007 do not support the anthropogenic interpretation of global warming during this period. This key result is shown graphically in Fig. 3 where the vertical axis measures the component of global temperature that is unexplained by solar irradiance according to our estimates. In panel a the horizontal axis measures the anomaly in the anthropogenic trend when the latter is derived from forcings of carbon dioxide, methane and nitrous oxide. In panel b the horizontal axis measures this anthropogenic anomaly when apart from these greenhouse gas forcings, it includes tropospheric aerosols and black carbon. Panels a and b both show that there is no relationship between temperature and the anthropogenic anomaly, once the warming effect of solar irradiance is taken into consideration.This is Fig. 3a:
Interestingly, the authors also conclude that the data admit the possibility that CO2 and other “greenhouse gases” could contribute to to a temporary increase in global temperatures:
However, we find that greenhouse gas forcings might have a temporary effect on global temperature. This result is illustrated in panel c of Fig. 3 in which the horizontal axis measures the change in the estimated anthropogenic trend. Panel c clearly shows that there is a positive relationship between temperature and the change in the anthropogenic anomaly once the warming effect of solar irradiance is taken into consideration.
Other scientists will weigh in on these findings, as the debate over climate continues to rage. Still, it is increasingly clear that the most reliable and sophisticated scientific work tends to show that the anthropogenic global warming hypothesis is wrong. In that sense, it is fair to say that a consensus is emerging.