[listenhillary]

Where exactly did they get the gobal temperatures in 1921 and 1934? The ocean temperatures were sampled from...? How many global sample sites and how many readings in 1921 and 1934?

[Old Professer]

Before buoys became commonplace and pre-satellite age, ocean going ships used to drop buckets into the water and measure the water temperature after being brought back aboard; air temps were were measured by hand with mercury thermometers, bulb style. All ships kept logs.

Today it is all electronic with self-correcting instruments of unstated accuracy.