In measurement, the least precise instruments making the measurements determine the precision of the data.
Mathematical or statistical operations do not add precision to the data.
The widely used Automatic Surface Observing System (ASOS) temperature instruments used at airports have a precision of +/- 1 degree C (almost +/- 2 degrees F.).
Surface temperature data cannot be more precise than these measuring instruments.
Yet government agencies such as NASA (GISS) claim their temperature data, after mathematical manipulations, has a margin of error of +/- 0.1 degrees C.
Even worse, NASA reports the average temperature of the planet to the gullible public in hundredths of a degree C.!
This is grossly false precision.
Any assumption that individual measurement errors will "cancel each other out" needs to be demonstrated ... but has never been demonstrated ... and will never be demonstrated.
Reporting that 2016 was warmer than 2015 by 0.02 degree C. is nonsense, given the accuracy of the measuring instruments.
The claim that humans can predict the future climate is also nonsense.
And the claim that adding CO2 in the air will cause runaway warming is nonsense too.
Earth has had CO2 levels higher than today for most of the past 4.5 billion years -- up to 10x to 20x higher levels of CO2 than today -- with no evidence of any runaway warming in the past (or else we wouldn't be hear to debate climate change!).