Guest contribution by Willis Eschenbach
After my last post on ocean surface warming, titled “How Global Warming Isn’t”, I had to think about the warming of the upper part of the ocean. So I got the ocean heat content (OHC) data for the top 700 meters of the ocean from the wonderful spot KNMI. If you look under Monthly Observations, you will find a variety of the most fascinating records. Under “Heat Content” on this page you will find the OHC data from the National Oceanic Data Center (NODC) with a depth of 0 to 700 meters. At the very bottom of this page is a link that will download a 196 megabyte grid NetCDF file that contains the data I am using. (Large file, click at your own risk.)
And what did I find? Well, I’m a visual guy. I mean, I can do arithmetic, but it only makes sense when it appears as an image on the canvas. So here are my graphics. I’m interested in changes in ocean heat content, so these are two views of those trends.
Figures 1 and 2. Decadal trends in ocean heat content in exajoules (1018 joules) per decade.
I love climate science because I am always amazed at what I find. What would be better? It’s like Christmas every day.
My first surprise? There are a number of giant, oceanic, slow whirlpool type vortices that I’ve seen before. They start at the southern tip of Africa and extend to Australia. I knew about them because they are visible in graphs of satellite sea surface elevation data. What I hadn’t noticed, however, is that these eddies are mixing warm surface water into the depths. This is indicated by the orange / yellow line of increased underwater heat stretching from Africa below Australia.
And if you mix some warm surface water down, other cool, deep water has to come up … as indicated by the appropriate series of areas south of the eddy surrounded by black and white lines showing areas that have actually lost heat since 1955 to have. Who knew Certainly not me.
What else surprised me? The turbulence of the Gulf Stream, when it interacts with the ocean floor topography along the US east coast, also mixes warm surface water downward … and the corresponding upward movement of cold subsurface water occurs south of Greenland.
I’ve long wondered how less dense, warmer water could mix down into denser, cooler, deeper water. Well there are some places where it happens.
Finally, I looked at the actual temperature change represented by these exajoules of energy changes. I mean, how big is an exajoule when it’s at home? I’m sure i don’t know.
But as I said, I can count. So I converted the slow increase in exajoules of heat content to degrees Celsius of slow warming. Here is the result:
Figure 3. Global change in sea temperature, surface to 700 meters depth from 1955 to 2020
A quarter of a degree in half a century?
Now I read on about how fish change position in response to ocean warming. But it seems extremely doubtful to me because the changes have been so small. Over the past fifty years the ocean has warmed about 0.005 ° C per year … and call me crazy, but I just don’t think the fish and other marine life are so sensitive to temperature that a quarter of an hour will change degrees in half a century get them to leave their happy home.
For one, the vertical temperature change in the open ocean is often on the order of 1 ° C per 40 meters vertical or so. Here are some Argo swimmer profiles of the top 200 meters.
Figure 4. Vertical temperature profiles of the Argo float data for the North Pacific.
And that means that a fished or other subaquatic resident, if he walks up or down about ten meters, has already survived the dreaded change in temperature of a quarter of a degree …
In addition, many millions of oceanic fish, shrimp and copepods migrate every night from 800 to 1000 meters depth to about 100 meters depth and then go back down at dawn … which means that they can happily withstand 5 ° – 10 ° change in temperature each night. So I very much doubt that in half a century they will be affected by a temperature change of a quarter of a degree.
And by tonnage, this daily vertical migration is the largest movement of living things on the planet. So we’re not talking about a few fish here and there.
This is the bottom line. If the creatures of the world on land and at sea were as sensitive to temperature as the alarmists would have us believe, these beings (and we humanoids too) would all have been extinct. And as far as I can tell, it hasn’t happened yet … at least not yet.
My very best wishes to all living things, both terrestrial and aquatic,
w.
As always: When you comment, I ask that you quote the exact words you are talking about so that we can all know what and who you are replying to.
One final note: In addition to traversing the temperature range of five degrees or more on a daily basis, it should be noted that as the millions of tons of aquatic life move from 1000 meters to 100 meters depth and back every night, they experience a pH change of about half a pH unit.
In other words, every night, under IPCC assumptions, they experience a greater pH change than we would expect in the ocean in the next century. You know … the dreaded pH change that’s supposed to kill ocean creatures a million times over. But instead, as Darwin supposedly mentioned once or twice, living things evolved to … well … survive.
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