Let me ‘splain.
If you want to know exactly where your dog is, you could put at GPS sensor in the middle of it’s body, perhaps near the pancreas. It would give you an average position for your dog, and would be most accurate most of the time.
If you put the GPS sensor on the tip of the dog’s tail, and used that to estimate where your dog is, you would be nearly wrong much of the time, even if over the long term this would be a good estimate for where your dog has been.
More importantly, if you wanted to measure the movement of your dog, the GPS sensor in the middle of the dog’s body would tell you pretty accurately if the dog is moving or still. But a GPS sensor on the tip of the dog’s tail would often indicate movement when the dog is, essentially still (but wagging its tail).
The question has been brought up: Is global warming stalled? People suggest this because atmospheric temperatures have not gone up as much as they might be expected to go up if we used a straight line matched to the last 30 or 40 years of data. Like this:
(That graph is from here.)
Thinking that this means that global warming has stalled, however, is like thinking that your dog is on the bottom step of your porch jumping up and down, when really, it is on the top step of your porch sleeping (and the dog’s tail is hanging down by the lower setp, wagging because it is having a happy-dream).
When the sun’s light reaches the earth, a certain amount of it bonces off shiny things and goes back into space. The light that does not bounce off is absorbed momentarily by atoms and converted to heat. That heat eventually goes out into out space as well, but it takes time. Greenhouse gasses in the atmosphere cause the departure of the heat to slow down. Increased greenhouse gasses have caused the entire system to heat up because the atmosphere does a poorer job conducting this heat to the upper reaches of the atmosphere and beyond.
But, only a tiny percentage of the sun’s energy that is converted to heat actually contributes to warming of the atmosphere and thus to things like how hot it is outside, or how much evaporation there is (which causes both drought and heavy rain, depending). About 93.4% of this energy actually goes into the ocean, 2.3% into the air, and the rest into other things.
For this reason, when you focus on just the heat in the atmosphere (or, for that matter, just the atmosphere and the surface of the sea), to measure or describe global warming, it is like tracking the tip of your dog’s tail to determine its location, instead of the body of the dog. It will work, and over time be a good approximation of global warming/dog location, but over shorter time scales, looking only at the atmosphere/tail will show more variation than is useful in answering the important questions.
Those important questions being “Is global warming continuing?” and “Where is my dog?”
Don’t let the tail wag the dog.