Climate change is here — and worse than we thought

[ben4vols]

Dr. Hansen was referring to the global incidence of summertime 3σ deviations, not solely the U.S. basis. Had Dr. Christy examined GISS, he would find that both the 1951-80 and his recommended 1931-80 periods yield remarkably similar results on a global basis.

1951-80 (June-August):

Mean anomaly: -0.0003°C

Standard Deviation: 0.0987°C

1931-80 (June-August):

Mean anomaly: -0.0058°C

Standard Deviation: 0.0930°C

In short, Dr. Christy's argument that the 1951-80 baseline is not representative does not hold merit in the global context against which Dr. Hansen is examining areas of extreme summer heat.

Is this using Tmax as suggested by Dr. Christy? Also the 51-80 baseline was a cherry pick. No other way around it. As Dr. Christy shows in his graph.

[PhillipS]

Is this using Tmax as suggested by Dr. Christy? Also the 51-80 baseline was a cherry pick. No other way around it. As Dr. Christy shows in his graph.

1951 - 1980 is the baseline GISS has been using for a long time. So your claim of cherry-picking is nonsense

[donsutherland1]

Is this using Tmax as suggested by Dr. Christy? Also the 51-80 baseline was a cherry pick. No other way around it. As Dr. Christy shows in his graph.

The reality is that there are differing opinions on the climate reference period. On a global basis, 1931-80 and 1951-80 are almost identical in terms of variability.

As data homogenization addresses the biases contained in the raw data, the argument for using only Tmax is not overwhelming. However, if Dr. Christy prefers an analysis using only maximum temperatures, he should present such an analysis. Such an analysis would add detail to the larger temperature discussion as it relates to maximum temperature trends.