I came across an article in the Guardian today (The oceans are warming so fast, they keep breaking scientists’ charts) that is lightly-written, yet sobering to read.
Basically, the problem with climate change/global warming is that the Earth’s systems, in combination, hold more heat energy than they used to. In the past, there have been confusions because air temperatures rose for a while, then stopped rising, and denialists assumed this meant that global warming had stopped, too.
Alas, not so. The heat was still accumulating but in a different place, and when scientists looked in the right place, they found that the air temperatures has stopped rising because the oceans had taken over and were warming instead.
So, to get a more accurate idea of how much global warming is taking place, you need to measure both the rise in air temperatures and the rise in ocean temperatures, and NOAA has been doing that. The combined figures reveal how much more energy is being held at Earth’s surface (give or take a few thousand metres either way) as time passes and climate change really digs its teeth in.
Soberingly, NOAA have had to rescale their ocean temperature graphs, as the figures are now off the scale, and this is not the first time they’ve had to do so.
NOAA’s webpage on ocean heat content is here.