How do you measure the Surface temperature of the Global Earth? This has only been achievable using the temperature sensors (micro bolometers arrays) on Satellite space craft. The temperature in the northern hemisphere is highly dependent on ocean currents (thermal flows and heat distribution) for example.

The temperature record even going back more than the last 20+ years is totally incomplete. And the last 20+ years has shown no change in temperature.

For example if we take the thermometer readings record from a thermometer for the last 150 years say based in Los Angeles then you will see significant temperature increases but it won't be due to 'Global' warming but 'local' warming.