The comparison with opioids is erroneous because prescribed opiates are given to a patient to take home, allowing abuse and diversion. MDMA use will take place at a medical practice. No abuse or diversion will take place (barring theft).
The SST adjustments have a larger impact on global temperatures than the land adjustments. Hence the global temperature has been adjusted higher relative to the raw data for the period before 1940.
It is due to the adjustments of the ocean temperature data. The SST data has been adjusted upward. Due to the adjustments the global temperature is estimated to be warmer in the past than the raw data show (http://variable-variability.blogspot.com.au/2015/02/homogeni...)
Uh, you do know that sea level rises for several reasons, right? Thermal expansions. Oh and ice melt of glaciers and sea ice isn't linear. Why not read some peer reviewed science?