Global warming is the increase in average temperature of the oceans and air near the earth's surface occurred. (slideplayer.com)
If so, how much confidence should we have in the ability of these scientific instruments to measure temperature of the ocean that accurately? (realclimate.org)
The error of each estimate of global average temperature of an ocean layer remains closer to that of the instruments, or about 0.1 C. (joannenova.com.au)