Average Global Temperatures since 1850
&quot;The data are a mix of the CRUTEM4 land-surface air temperature dataset and the HadSST3 sea-surface temperature (SST) dataset. The HadCRUT4 data are neither interpolated nor variance adjusted.&quot;<p>This is your typical half-truth (lie of omission). Even if the HadCRUT4 folks themselves don&#x27;t make these kinds of adjustments, the folks who provide the data sets which HadCRUT4 is based on most certainly do.