A Study of Urban Heat Island (UHI) in Singapore

Here.

Below is Figure 3 from the link above (click to enlarge):



Note that the difference between the coolest and warmest points was several degrees Celsius.

Also note that the implementing the Kyoto protocol (over a 50-year period) would supposedly decrease the earth's temperature by a total of only about .07 degrees Celsius.

This means that the total temperature "benefit" of Kyoto could conceivably be dwarfed by urban heat island bias in our surface temperature data.