What was done
The authors investigated the association between temperature and daily mortality in Shanghai from 1 June 2000 to 31 Dec 2001.

What was learned
A V-like relationship between total mortality and temperature was found that had a minimum mortality risk at 26.7°C.  Above this optimum temperature for life in Shanghai, Kan et al. note that "total mortality increased by 0.73% for each degree Celsius increase; while for temperatures below the optimum value, total mortality decreased by 1.21% for each degree Celsius increase."

What it means
The net effect of a warming of the climate of Shanghai would likely be reduced mortality on the order of 0.5% per degree Celsius increase in temperature, or perhaps even more, in light of the fact that the warming of the past few decades has been primarily due to increases in daily minimum temperatures, where the data of Kan et al. reveal mortality rates in Shanghai to be about 50% greater than they are at maximum temperatures typical of the city.  Hence, with respect to the past, it can be appreciated that the recovery of the earth from the global chill of the Little Ice Age has had a positive effect on the health of the people of Shanghai that continues to this day and should continue into the foreseeable future if the planet continues to warm.